Patent Publication Number: US-2022239153-A1

Title: Structural body, system, and structural product

Description:
TECHNICAL FIELD 
     The present invention relates to a structural body, a system, and a structural product. 
     BACKGROUND ART 
     Conventionally, a structural body including a three-dimensional net shape as typified by a lattice structure, etc. has been used. 
     For example, Patent Literature (PTL) 1 discloses a technique that uses a lattice structure to control mechanical properties such as inhibition of a decrease in stiffness. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] Japanese Unexamined Patent Application Publication No. 2015-93461 
     SUMMARY OF INVENTION 
     Technical Problem 
     For the structural body including the three-dimensional net shape, techniques of controlling mechanical properties have been mainly developed, whereas techniques for exerting a novel function other than the mechanical properties have not been focused on. 
     In view of the above, an object of the present invention is to provide a structural body that exerts a novel function, using a structural body including a three-dimensional net shape. 
     Solution to Problem 
     In order to achieve the above-described object, a structural body according to an aspect of the present invention includes: a three-dimensional net shaped body including a plurality of net lines that form a three-dimensional net shape; and a plurality of objects respectively present in two or more of a plurality of spaces partitioned by the plurality of net lines. In the structural body, the plurality of objects are each a mobile object that moves within one of the plurality of spaces or moves over two or more of the plurality of spaces. 
     In addition, a system according to an aspect of the present invention includes the above-described structural body; and an energy supply device that moves the plurality of objects by supplying energy to the plurality of objects. 
     In addition, a structural product according to an aspect of the present invention includes the above-described structural body. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide a structural body that exerts a novel function. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a schematic diagram of a system according to Embodiment 1. 
         FIG. 1B  is an enlarged perspective view of one space which is one of a plurality of spaces according to Embodiment 1. 
         FIG. 2  is a cross-sectional view of a structural body taken along the line II-II of  FIG. 1A . 
         FIG. 3  is a schematic diagram of a system according to Embodiment 2. 
         FIG. 4  is a cross-sectional view of a structural body taken along the line IV-IV of  FIG. 3 . 
         FIG. 5A  is a schematic diagram of a structural product according to Embodiment 3. 
         FIG. 5B  is an enlarged perspective view of one of a plurality of spaces according to Embodiment 3. 
         FIG. 6  is a front view of the structural product illustrated in  FIG. 5A . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following describes in detail a structural body according to an embodiment of the present disclosure, with reference to the drawings. It should be noted that each of the embodiments described below shows a specific example of the present invention. The numerical values, shapes, materials, structural components, the disposition and connection of the structural components, etc. described in the following embodiments are mere examples, and do not intend to limit the present invention. Among the structural components in the embodiments described below, those not recited in the independent claims will be described as optional structural components. 
     In addition, each diagram is a schematic diagram and not necessarily strictly illustrated. Accordingly, for example, scale sizes, etc. are not necessarily exactly represented. In each of the diagrams, substantially the same structural components are assigned with the same reference signs, and redundant descriptions will be omitted or simplified. 
     In addition, a term, such as “parallel” or “perpendicular”, representing a relationship between the components as well as a term, such as “square” or “rectangle”, representing a form, and a numerical range are used in the present description. Such terms and range are each not representing only a strict meaning of the term or range, but implying that a substantially same range, e.g., a range that includes even a difference as small as few percentages, is connoted in the term or range. 
     Furthermore, an x-axis, a y-axis, and a z-axis represent three axes of a three-dimensional orthogonal coordinate system in the Description and Drawings of the present application. In each of the embodiments, two axes parallel to one of boundary planes that define a plurality of spaces are an x-axis and a y-axis, and a direction perpendicular to the boundary plane is a z-axis direction. 
     Embodiment 1 
     Configuration 
     First, the configuration of system  1000  according to the present embodiment will be described with referenced to  FIG. 1A  and  FIG. 1B . 
       FIG. 1A  is a schematic diagram of system  1000  according to Embodiment 1. System  1000  according to the present embodiment is a system including structural body  100  and energy supply device  200 . In addition, system  1000  according to the present embodiment includes mounting base  201  on which structural body  100  is mounted. Structural body  100  includes three-dimensional net shaped body  10  and a plurality of objects  40  which are mobile objects. Energy supply device  200  is a device that moves the plurality of objects  40  by supplying energy to the plurality of objects  40 . For example, system  1000  is a system in which energy supply device  200  supplies energy to the plurality of objects  40  to move the plurality of objects  40 , thereby causing structural body  100  to exert a novel function of structural body  100 . System  1000  according to the present embodiment is a system in which, for example, energy supply device  200  supplies energy to the plurality of objects  40  to move the plurality of objects  40 , thereby causing structural body  100  to rotate. 
     Energy supply device  200  according to the present embodiment is a device that includes an electromagnet. Energy supply device  200  according to the present embodiment includes, for example, a coil, a magnetic material on which the coil is wound, and a power supply that is connected to the coil. Energy supply device  200  according to the present embodiment is capable of generating a magnetic force and a magnetic field, as a result of a current flowing through the coil. The plurality of objects  40  are supplied with energy as a result of generation of the magnetic field by energy supply device  200  according to the present embodiment. Energy supply device  200  according to the present embodiment is located on the upper side (on the positive side of the z-axis) of structural body  100 . Energy supply device  200  may be located on the upper side of structural body  100  and spaced apart from structural body  100  by column support  202  connected to mounting base  201 . 
     Next, structural body  100  according to the present embodiment will be described. As described above, structural body  100  includes three-dimensional net shaped body  10  having a plurality of net lines  20 , and objects  40  that are respectively present in two or more spaces  30  of a plurality of spaces  30  partitioned by the plurality of net lines  20 . Structural body  100  according to the present embodiment is mounted, for example, on mounting base  201 . 
     It should be noted that, although structural body  100  is located on the lower side (on the negative side of the z-axis) of energy supply device  200  according to the present embodiment, the positional relationship between structural body  100  and energy supply device  200  is not limited to this example. Furthermore, structural body  100  and energy supply device  200  may be in direct contact with each other. In other words, any positional relationship may be established as long as the plurality of objects  40  included in structural body  100  can receive energy that is supplied by energy supply device  200 . 
     The plurality of net lines  20  included in three-dimensional net shaped body  10  are components that form the three-dimensional net shape. In addition, the plurality of net lines  20  are components that make up the framework of three-dimensional net shaped body  10 . Although the plurality of net lines  20  form the three-dimensional net shape, it is not necessary that each of the plurality of net lines  20  is woven. For example, the plurality of net lines  20  may be shaped to branch off and extend from a portion of the plurality of net lines  20 . In addition, for example, the plurality of net lines  20  may be shaped to be connected to one another. 
     Each of the plurality of net lines  20  according to the present embodiment has a shape of a straight line, but is not limited to this example. For example, each of the plurality of net lines  20  may have a curved shape, or a combination of a shape of a straight line and a curved shape. Each of the plurality of net lines  20  may have the same or different line thickness. 
     The plurality of net lines  20  according to the present embodiment includes a plurality of primary net lines  21  having a larger line thickness and a plurality of secondary net lines  22  having a smaller line thickness. According to the present embodiment, the line thickness of the plurality of primary net lines  21  is larger than the line thickness of the plurality of secondary net lines  22 . 
     Each of the plurality of primary net lines  21  according to the present embodiment extends linearly in a direction along corresponding one of the x-axis, the y-axis, and the z-axis. 
     Among the plurality of primary net lines  21 , lines extending in the x-axis direction are parallel to each other and evenly spaced. Among the plurality of primary net lines  21 , lines extending in the y-axis direction are parallel to each other and evenly spaced. Among the plurality of primary net lines  21 , lines extending in the z-axis direction are parallel to each other and evenly spaced. 
     In addition, according to the present embodiment, among the plurality of primary net lines  21 , the lines extending in the x-axis direction, the lines extending in the y-axis direction, and the lines extending in the z-axis direction are arranged with the same spacing. It should be noted that, among the plurality of primary net lines  21 , the lines extending in the x-axis direction, the lines extending in the y-axis direction, and the lines extending in the z-axis direction may be arranged with different spacing. 
     According to the configuration of the plurality of primary net lines  21  as described above, the plurality of primary net lines  21  are shaped in a three-dimensional lattice shape. 
     In addition, as will be described later, the plurality of spaces  30  according to the present embodiment each have a cubic shape. 
     The plurality of spaces  30  are regions partitioned by the plurality of net lines  20 , and thus the plurality of primary net lines  21  according to the present embodiment are arranged at positions corresponding to the respective sides of cubes (the plurality of spaces  30 ). 
     In regard to the plurality of secondary net lines  22  included in the plurality of net lines  20  according to the present embodiment, the details will be described with referenced to  FIG. 1B . 
     The plurality of spaces  30  are regions partitioned by the plurality of net lines  20 . In other words, the plurality of spaces  30  are three-dimensional regions partitioned by the plurality of net lines  20 . 
     The plurality of spaces  30  according to the present embodiment are regions mainly partitioned by the plurality of primary net lines  21 . However, the plurality of spaces  30  may be regions partitioned by the plurality of primary net lines  21  and the plurality of secondary net lines  22 . In other words, the plurality of spaces  30  may have a shape resulting from combining the plurality of primary net lines  21  and the plurality of secondary net lines  22 . 
     As described above, among the plurality of primary net lines  21 , the lines extending in the x-axis direction, the lines extending in the y-axis direction, and the lines extending in the z-axis direction are arranged with the same spacing. Accordingly, the plurality of spaces  30  according to the present embodiment each have a cubic shape. 
     The shape of each of the plurality of spaces  30  is not limited to the cubic shape. For example, the shape of each of the plurality of spaces  30  may be any other shape such as a cuboid shape, a pyramidal shape, a prismatic shape, a conical shape, a cylindrical shape, a spherical shape, a regular polyhedral shape, etc., or a combination of these shapes. In addition, the plurality of spaces  30  may have respectively different shapes. Furthermore, the plurality of spaces  30  may have respectively different sizes. For example, the plurality of spaces  30  may be a combination of space  30  having a larger cubic shape and space  30  having a smaller cubic shape. 
     In addition, when the first direction, the second direction, and the third direction are directions perpendicular to one another, the plurality of spaces  30  are disposed along the first direction, the second direction, and the third direction. According to the present embodiment, for example, the x-axis direction is the first direction, the y-axis direction is the second direction, and the z-axis direction is the third direction. More specifically, among the plurality of spaces  30  according to the present embodiment, three are arranged in the x-axis direction, two are arranged in the y-axis direction, and two are arranged in the z-axis direction. It should be noted that the respective numbers of the plurality of spaces  30  arranged in the x-axis direction, in the y-axis direction, and in the z-axis direction are not limited to the above-described example. 
     As described above, three-dimensional net shaped body  10  includes the plurality of net lines  20 . According to the present embodiment, the plurality of spaces  30  partitioned by the plurality of net lines  20  each have a cubic shape, and are respectively arranged in the x-axis direction, in the y-axis direction, and in the z-axis direction. As described above, three-dimensional net shaped body  10  has a configuration in which a three-dimensional lattice is continuously repeated. Accordingly, three-dimensional net shaped body  10  can be said also to be a lattice structure body. In addition, since three of the plurality of spaces  30  are arranged in the x-axis direction, two of the plurality of spaces  30  are arranged in the y-axis direction, and two of the plurality of spaces  30  are arranged in the z-axis direction, the shape of three-dimensional net shaped body  10  is a cuboid shape. 
     It should be noted that, when the shape of each of the plurality of spaces  30  is not a cubic shape unlike the above-described example, the shape of three-dimensional net shaped body  10  is also not a cuboid shape. The shape of three-dimensional net shaped body  10  may be any other shape such as a cuboid shape, a pyramidal shape, a prismatic shape, a conical shape, a cylindrical shape, a spherical shape, a regular polyhedral shape, etc. 
     In addition, three-dimensional net shaped body  10  according to the present embodiment has a high rigidity. Accordingly, even when a force is applied to three-dimensional net shaped body  10 , the amount of deformation is quite small. 
     Object  40  is present in each of two or more spaces  30  of the plurality of spaces  30 . In other words, in structural body  100  according to the present embodiment, there are two or more objects  40 , i.e., the plurality of objects  40 . The plurality of objects  40  are mobile objects that move. More specifically, the plurality of objects  40  each move within one space  30  of the plurality of spaces  30 , and/or move over two or more spaces  30  of the plurality of spaces  30 . The plurality of objects  40  according to the present embodiment each move within one space  30  of the plurality of spaces  30 . In contrast, the plurality of objects  40  according to the present embodiment each do not move over two or more spaces  30  of the plurality of spaces  30 . 
     In addition, according to the present embodiment, the plurality of objects  40  comprise four objects  40 . Four objects  40  are respectively present in four spaces  30  located on the most positive side of the x-axis among the plurality of spaces  30 . It should be noted that spaces  30  in which the plurality of objects  40  are present are not limited to the above-described example. The plurality of objects  40  are respectively present in two or more spaces  30  of the plurality of spaces  30 , according to a function of structural body  100 . 
     The plurality of objects  40  according to the present embodiment are solid substances. The plurality of objects  40  include at least one of a metallic material, an inorganic compound material, or an organic compound material. The metallic material, for example, may be a material including metal of a single type, or may be an alloy material including metal of two or more types. The inorganic compound material may be oxide, nitride, sulfide, halide, etc. The inorganic compound material may be a material derived from inorganic acid such as hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, carbonic acid, boracic acid, hydrofluoric acid, etc. The organic compound material may be a resin including a high polymer compound. According to the present embodiment, the plurality of objects  40  include a material that exhibits ferromagnetic properties, such as iron, cobalt, nickel, ferrite, or the like. More specifically, the plurality of objects  40  according to the present embodiment contain iron. For this reason, the plurality of objects  40  according to the present embodiment exhibit ferromagnetic properties. 
     The plurality of objects  40  according to the present embodiment each have a spherical shape. However, the shape of the plurality of objects  40  is not limited to this example. The shape of the plurality of objects  40  may be a cuboid shape, a pyramidal shape, a prismatic shape, a conical shape, a cylindrical shape, an ovoid shape, etc. 
     The shape of the plurality of objects  40  is a spherical shape, and thus the plurality of objects  40  do not have a corner or a protrusion. For this reason, it is possible to inhibit the plurality of objects  40  from being snagged inside the plurality of spaces  30 , allowing the plurality of objects  40  to move smoothly inside the plurality of spaces  30 . 
     Next, boundary plane  31  included in the plurality of spaces  30  and the plurality of secondary net lines  22  will be described in detail with referenced to  FIG. 1B . 
       FIG. 1B  is an enlarged perspective view of space  30  which is one of the plurality of spaces  30  according to Embodiment 1. 
     The plurality of spaces  30  according to the present embodiment include boundary plane  31  that defines the plurality of spaces  30 . Boundary plane  31  is a two-dimensional region sectioned by the plurality of net lines  20  in the plurality of spaces  30  including this boundary plane  31 . Since each of the plurality of spaces  30  according to the present embodiment has a cubic shape, each of the plurality of spaces  30  according to the present embodiment includes six boundary planes  31 . Boundary planes  31  include a plane that is an interface between two adjacent spaces  30  among the plurality of spaces  30 . In addition, one or more of boundary planes  31  are included in outermost planes located outermost of three-dimensional net shaped body  10 . As described above, since three-dimensional net shaped body  10  has a cuboid shape, the outermost planes are six planes that define the cuboid shape. In addition, according to the present embodiment, one of the outermost surfaces is a surface at which structural body  100  and mounting base  201  are in contact with each other. 
     Next, the plurality of secondary net lines  22  will be described. 
     Each of the plurality of secondary net lines  22  according to the present embodiment extends linearly in a direction along corresponding one of the x-axis and the z-axis. 
     Among the plurality of secondary net lines  22 , those extending in the x-axis direction are each located at the center between adjacent ones of the plurality of primary net lines  21  which extend in the x-axis direction. According to the present embodiment, those extending in the x-axis direction among the plurality of secondary net lines  22  are located on boundary planes  31  parallel to the xy plane and on boundary planes  31  parallel to the xz plane. 
     Among the plurality of secondary net lines  22 , those extending in the z-axis direction are each located at the center between adjacent ones of the plurality of primary net lines  21  which extend in the z-axis direction. According to the present embodiment, those extending in the z-axis direction among the plurality of secondary net lines  22  are located on boundary planes  31  parallel to the yz plane. 
     In addition, on boundary planes  31 , opening portions  31   a  enclosed by the plurality of primary net lines  21  and the plurality of secondary net lines  22  are present. Whether the plurality of objects  40  move over two or more spaces  30  of the plurality of spaces  30  depends on the size of opening portions  31   a.  In other words, as opening portions  31   a  increase in size, the plurality of objects  40  more likely to move over two or more spaces  30  of the plurality of spaces  30 . On the other hand, as opening portions  31   a  decrease in size, the plurality of objects  40  less likely to move over two or more spaces  30  of the plurality of spaces  30 . 
     As illustrated in  FIG. 1B , according to the present embodiment, opening portions  31   a  each have a rectangular shape. In  FIG. 1B , opening portion  31   a  is indicated by dotted lines defining a quadrilateral shape. In addition, according to the present embodiment, when the length of opening portion  31   a  in the crosswise direction is denoted as X, X is shorter than the diameter of each of the plurality of objects  40  having a spherical shape. The plurality of primary net lines  21  and the plurality of secondary net lines  22  included in the plurality of net lines  20  according to the present embodiment are arranged in a positional relationship as described above. 
     Accordingly, in the present embodiment, the plurality of objects  40  and the plurality of net lines  20  have a configuration that prevents the plurality of objects  40  from moving over two or more of the plurality of spaces  30 . 
     According to this configuration, the plurality of objects  40  are capable of staying within one of the plurality of spaces  30 . 
     It should be noted that, one secondary net line  22  is provided on one boundary plane  31  according to the present embodiment, but the present invention is not limited to this example. For example, two or more secondary net lines  22  may be disposed on one boundary plane  31 . In addition, in the case where two or more secondary net lines  22  are disposed on one boundary plane  31 , the two or more secondary net lines  22  need not necessarily be parallel to each other. 
     For example, the two or more secondary net lines  22  may intersect with each other in a cross shape or in a mesh shape. 
     Structural body  100  according to the present embodiment has a configuration as described above. Here, a manufacturing method of structural body  100  according to the present embodiment will be described. 
     Manufacturing Method 
     First, a method of manufacturing three-dimensional net shaped body  10  included in structural body  100  according to the present embodiment will be described. 
     Three-dimensional net shaped body  10  can be manufactured using a three-dimensional (3D) printer (additive manufacturing). In other words, the plurality of net lines  20  included in three-dimensional net shaped body  10  can be manufactured using a 3D printer. 3D printers laminate a plurality of layers using three-dimensional computer data that represents a three-dimensional manufacturing target that is desired to be manufactured, thereby manufacturing the three-dimensional manufacturing target. Manufacturing methods that use 3D printers include, for example, a material extrusion method, a liquid tank photopolymerization method, a material injection method, a binder injection method, a powder bed melt bonding method, etc. 
     According to the present embodiment, three-dimensional net shaped body  10  is manufactured using the material extrusion method. The material extrusion method is carried out according to the procedure described below. 
     First, a filament fused material is obtained by fusing a filament. Three-dimensional net shaped body  10  is configured using this filament. Next, the filament fused material is discharged from a nozzle to a predetermined position of a manufacturing stage, based on three-dimensional computer data. Layers of the filament fused material are laminated as a result of repeating the process of discharging the filament fused material, and thereby the three-dimensional manufacturing target that is desired to be manufactured can be obtained. Alternatively, the three-dimensional manufacturing target that is desired to be manufactured may be obtained as a result of removing a water-soluble supporting material after the manufacturing. 
     In addition, it is sufficient if the filament has a thermal fusion property. For example, the filament may be made including a thermoplastic resin and a filler (filling agent). The filler may be a material that contains a metallic powder, a wood powder, or a phosphorescent material. In addition, since the filler can be combined with a resin to provide the resin with a new property, the filler is selected according to the application. 
     According to the present embodiment, three-dimensional net shaped body  10  and the plurality of net lines  20  are manufactured using an acrylonitrile-butadiene-styrene (ABS) resin material as a filament. It should be noted that, since the ABS resin material is a material having a high rigidity according to the present embodiment, three-dimensional net shaped body  10  has a high rigidity. 
     Next, the plurality of objects  40  according to the present embodiment will be described. According to the present embodiment, the plurality of objects  40  are disposed to be present in the plurality of spaces  30  in the middle of the manufacturing of three-dimensional net shaped body  10 . In other words, the manufacturing of three-dimensional net shaped body  10  is suspended in the middle of the laminating of layers, and the manufacturing of three-dimensional net shaped body  10  is started again after the plurality of objects  40  are disposed. 
     Structural body  100  according to the present embodiment is manufacture through the manufacturing method as described above. 
     The following describes the behavior of structural body  100  when energy supply device  200  generates a magnetic field. 
     Behavior at the time of Magnetic Field Generation 
       FIG. 2  is a cross-sectional view of structural body  100  taken along the line II-II illustrated in  FIG. 1A . More specifically,  FIG. 2  is a diagram which illustrates the behavior of structural body  100  at the time when a magnetic field is generated by energy supply device  200 , and magnetic force M 1  acts on the plurality of objects  40 , in system  1000  according to the present embodiment.  FIG. 2  illustrates in (a) a cross-sectional view of structural body  100  before magnetic force M 1  is generated, and in (b) a cross-sectional view of structural body  100  after magnetic force M 1  is generated. In addition, in order to prevent the diagram from being complicated, energy supply device  200 , mounting base  201 , and column support  202  are not illustrated in  FIG. 2 . 
     In structural body  100  according to the present embodiment, the plurality of objects  40  are present in spaces  30  that are located on the most positive side of the x-axis among the plurality of spaces  30 , as described above. 
     In addition, structural body  100  according to the present embodiment includes axis a. Axis a is a linear axis located at the center of one of the plurality of primary net lines  21  that are located on the most negative side of the x-axis and the most negative side of the z-axis, and extending in the y-axis direction. Axis a is immovable from the position to which axis a is fixed. According to the configuration as described above, structural body  100  according to the present embodiment is fixed rotatably about axis a. 
     In addition, energy supply device  200  according to the present embodiment is a device that includes an electromagnet, and generates a magnetic field. 
     As illustrated in (a) in  FIG. 2 , structural body  100  remains stationary prior to the generation of the magnetic field; that is, prior to the generation of magnetic force M 1 . 
     Meanwhile, as illustrated in (b) in  FIG. 2 , subsequent to the generation of the magnetic field, i.e., subsequent to the generation of magnetic force M 1 , structural body  100  moves in a rotational motion in rotation direction R about axis a as an axis of rotation. This phenomenon is explained by the following mechanism. 
     The plurality of objects  40  according to the present embodiment exhibit ferromagnetic properties. For that reason, each of the plurality of objects  40  is magnetized by the magnetic field. 
     Furthermore, magnetic force M 1  that is attracted to the electromagnet included in energy supply device  200  acts on the plurality of objects  40 . According to the present embodiment, since energy supply device  200  is located above structural body  100  (on the positive side of the z-axis), the direction of magnetic force M 1  is the positive direction of the z-axis. According to this configuration, the plurality of objects  40  each move within one space  30  of the plurality of spaces  30 . As a result of the plurality of objects  40  moving, the plurality of objects  40  come into contact with the plurality of net lines  20  and press the plurality of net lines  20  in the direction of magnetic force M 1 . This gives structural body  100  a force to move in the direction of magnetic force M 1 , in the same manner as the plurality of objects  40 . Meanwhile, structural body  100  is fixed rotatably about axis a. For that reason, structural body  100  moves in a rotational motion in rotation direction R about axis a as an axis of rotation. 
     According to the configuration as described above, structural body  100  is caused to exert a novel function of structural body  100 , as a result of the plurality of objects  40  moving. According to the present embodiment, structural body  100  moves in a rotational motion as a result of the plurality of objects  40  moving. In other words, the novel function is the function of the rotational motion of structural body  100 , according to the present embodiment. In addition, according to the present embodiment, the plurality of spaces  30  are regions sectioned by the plurality of net lines  20  included in three-dimensional net shaped body  10 , and the plurality of objects  40  are respectively present in two or more spaces  30  of the plurality of spaces  30 , according to the function of structural body  100 . In other words, the plurality of objects  40  are present in the plurality of spaces  30  that are most suitable according to the function of structure  100 . For that reason, structural body  100  is capable of exerting, to a maximum extent, the function of structural body  100 . 
     In addition, system  1000  according to the present embodiment includes structural body  100  and energy supply device  200  that moves the plurality of objects  40  by supplying energy to the plurality of objects  40 . 
     According to this configuration, system  1000  according to the present embodiment is capable of readily moving the plurality of objects  40 . Thus, as a result, structural body  100  according to the present embodiment readily exerts the novel function of structural body  100 . 
     The plurality of objects  40  each move within one space  30  of the plurality of spaces  30  according to the present embodiment, but are not limited to this example. The plurality of objects  40  may move over two or more spaces  30  of the plurality of spaces  30 . In this case as well, when the magnetic field is generated, the plurality of objects  40  come into contact with the plurality of net lines  20  and press the plurality of net lines  20  in the direction of magnetic force M 1 . 
     Structural body  100  according to the present embodiment includes axis a, but is not limited to this example. When structural body  100  does not include axis a; that is, when structural body  100  is not fixed rotatably, structural body  100  moves according to the direction of magnetic force M 1 . In other word, in this case, the novel function is a function of structural body  100  moving. 
     One object  40  is present in one space  30  according to the present embodiment, but the present invention is not limited to this example. For example, the plurality of objects  40  may include a first object and a second object, and the first object and the second object may be present in one space  30  of the plurality of spaces  30 . In other words, two objects  40  may be present in one space  30 . In addition, two or more objects  40  may be present in one space  30 . 
     According to this configuration, structural body  100  is capable of including more objects  40 . As a result, the force with which the plurality of objects  40  press the plurality of net lines  20  in the direction of magnetic force M 1  increases. In other words, structural body  100  is more likely to exhibit the novel function of structural body  100 . 
     Advantageous Effect, Etc. 
     As described above, structural body  100  according to the present embodiment includes three-dimensional net shaped body  10  that includes the plurality of net lines  20  that form the three-dimensional net shape. In addition, structural body  100  according to the present embodiment includes objects  40  that are respectively present in two or more spaces  30  of the plurality of spaces  30  partitioned by the plurality of net lines  20 . The plurality of objects  40  are each a mobile object that moves within one space  30  of the plurality of spaces  30 , and/or moves over two or more spaces  30  of the plurality of spaces  30 . 
     According to the above-described configuration, structural body  100  is caused to exert a novel function of structural body  100 , as a result of the plurality of objects  40  moving. According to the present embodiment, structural body  100  moves in a rotational motion as a result of the plurality of objects  40  moving. In other words, the novel function is the function of the rotational motion of structural body  100 , according to the present embodiment. In addition, according to the present embodiment, the plurality of spaces  30  are regions sectioned by the plurality of net lines  20  included in three-dimensional net shaped body  10 , and the plurality of objects  40  are respectively present in two or more spaces  30  of the plurality of spaces  30 , according to the function of structural body  100 . In other words, the plurality of objects  40  are present in the plurality of spaces  30  that are most suitable according to the function of structure  100 . For that reason, structural body  100  is capable of exerting, to a maximum extent, the function of structural body  100 . 
     In addition, in structural body  100  according to the present embodiment, the plurality of objects  40  and the plurality of net lines  20  have a configuration that prevents the plurality of objects  40  from moving over two or more of the plurality of spaces  30 . 
     According to the above-described configuration, the plurality of objects  40  are capable of staying within one of the plurality of spaces  30 . 
     In addition, in structural body  100  according to the present embodiment, the plurality of objects  40  include a first object and a second object, and the first object and the second object are present in one space  30  of the plurality of spaces  30 . 
     According to the above-described configuration, structural body  100  is capable of including more objects  40 . As a result, the force with which the plurality of objects  40  press the plurality of net lines  20  in the direction of magnetic force M 1  increases. In other words, structural body  100  is more likely to exhibit the novel function of structural body  100 . 
     In addition, in structural body  100  according to the present embodiment, the plurality of objects  40  each have a spherical shape. 
     According to the above-described configuration, the shape of each of the plurality of objects  40  does not have a corner or a protrusion. For this reason, it is possible to inhibit the plurality of objects  40  from being snagged inside the plurality of spaces  30 , allowing the plurality of objects  40  to move smoothly inside the plurality of spaces  30 . 
     In addition, system  1000  according to the present embodiment includes the above-described structural body  100  and energy supply device  200  that moves the plurality of objects  40  by supplying energy to the plurality of objects  40 . 
     According to the above-described configuration, system  1000  is capable of readily moving the plurality of objects  40 . Thus, as a result, structural body  100  according to the present embodiment readily exerts the novel function of structural body  100 . 
     Embodiment 2 
     Although the configuration in which the plurality of objects  40  are present in some of the plurality of spaces  30  has been described in Embodiment 1, the configuration is not limited to this example. Embodiment 2 is different from Embodiment 1 in that at least one of the plurality of objects  40 A is present in each of a plurality of spaces  30 A. It should be noted that, in Embodiment 2, the detailed description of the structural components common to Embodiment 1 will be omitted. 
     Configuration 
     First, the configuration of system  1000 A according to the present embodiment will be described with referenced to  FIG. 3 .  FIG. 3  is a schematic diagram of system  1000 A according to Embodiment 2. 
     System  1000 A according to the present embodiment is a system including structural body  100 A and energy supply device  200 A. In addition, system  1000 A according to the present embodiment includes mounting base  201 A on which structural body  100 A is mounted. Structural body  100 A includes three-dimensional net shaped body  10 A and a plurality of objects  40 A which are mobile objects. Energy supply device  200 A is a device that moves the plurality of objects  40 A by supplying energy to the plurality of objects  40 A. Energy supply device  200 A according to the present embodiment is a device that includes an electromagnet as with Embodiment 1, and is disposed on the negative side of the x-axis with respect to structural body  100 A. 
     For example, system  1000 A is a system in which energy supply device  200 A supplies energy to the plurality of objects  40 A to move the plurality of objects  40 A, thereby causing structural body  100 A to exert a novel function of structural body  100 A. According to the present embodiment, system  1000 A is a system in which energy supply device  200 A supplies energy to the plurality of objects  40 A to move the plurality of objects  40 A, thereby controlling the properties of structural body  100 A. In other words, system  1000 A controls, as a result of the plurality of objects  40 A moving, one or more of the properties of structural body  100 A which include an optical property, an electrical conduction property, a thermal conductive property, and a fluid resistance property. According to the present embodiment, system  1000 A is a system that controls the optical property of structural body  100 A. 
     In addition, three-dimensional net shaped body  10 A includes the plurality of net lines  20 A. The plurality of net lines  20 A include a plurality of primary net lines  21 A and a plurality of secondary net lines  22 A. The plurality of spaces  30 A are regions sectioned by the plurality of net lines  20 A. It should be noted that the three-dimensional net shaped body  10 A, the plurality of net lines  20 A, the plurality of spaces  30 A, the plurality of primary net lines  21 A, and the plurality of secondary net lines  22 A are the same in configuration as Embodiment 1. 
     Unlike structural body  100  described in Embodiment 1, structural body  100 A according to the present embodiment does not have axis a, and is fixed to a predetermined position. 
     According to the present embodiment, the plurality of objects  40 A are present in all of the plurality of spaces  30 A. In other words, at least one object  40 A is present in each space  30 A of the plurality of spaces  30 A. 
     The plurality of objects  40 A may exhibit the property of controlling light. For example, the plurality of objects  40 A may exhibit the property of absorbing, reflecting, or transmitting light. In addition, the plurality of objects  40 A may exhibit the property of controlling light as described above, and may further exhibit ferromagnetic property as described in Embodiment 1. For that reason, the plurality of objects  40 A may include two or more different materials. 
     The plurality of objects  40 A according to the present embodiment are configured to have a core-shell structure. The core-shell structure is a structure that includes two or more materials, in which one material forms a core and the other material forms a layer (shell) that surrounds the periphery of the core. According to the present embodiment, the core of each of the plurality of objects  40 A includes iron, as with Embodiment 1, and the shell of each of the plurality of objects  40 A includes a material having a high light absorptivity. More specifically, the shell of each of the plurality of objects  40 A includes a black material having a high visible light absorptivity. The black material is carbon black, for example. With such a configuration as described above, the plurality of objects  40 A exhibit the ferromagnetic property and further, absorb visible light. It should be noted that the black material is not limited to carbon black, but may be black pigment or black dye, for example, metal oxide. 
     The following describes the behavior of structural body  100 A when energy supply device  200 A generates a magnetic field. 
     Behavior at the time of Magnetic Field Generation 
       FIG. 4  is a cross-sectional view of structural body  100 A taken along the line IV-IV illustrated in  FIG. 3 . More specifically,  FIG. 4  is a diagram which illustrates the behavior of structural body  100 A at the time when a magnetic field is generated by energy supply device  200 A, and magnetic force M 2  acts on the plurality of objects  40 A, in system  1000 A according to the present embodiment.  FIG. 4  illustrates in (a) a cross-sectional view of structural body  100 A before magnetic force M 2  is generated, and in (b) a cross-sectional view of structural body  100 A after magnetic force M 2  is generated. In addition, in order to prevent the diagram from being complicated, energy supply device  200 A and mounting base  201 A are not illustrated in  FIG. 4 . 
     Energy supply device  200 A according to the present embodiment is a device that includes an electromagnet, and generates a magnetic field, as with Embodiment 1. 
     As illustrated in (a) in  FIG. 4 , prior to the generation of the magnetic field; that is, prior to the generation of magnetic force M 2 , the plurality of objects  40 A are present respectively in the plurality of spaces  30 A at random positions. 
     Here, it is assumed that light L is emitted to structural body  100 A. Light L is light that travels straight in the negative direction of the z-axis and is white light that consists of wavelengths in the visible light region. As described above, the plurality of objects  40 A according to the present embodiment absorb visible light. Accordingly, the light incident on the plurality of objects  40 A out of light L is absorbed by the plurality of objects  40 A and is quenched. Thus, the light incident on the plurality of objects  40 A out of light L cannot pass through structure  100 A. In other words, the light transmittance of structural body  100 A before the magnetic field is generated is low. 
     On the other hand, as illustrated in (b) in  FIG. 4 , after the magnetic field is generated; that is, after magnetic force M 2  is generated, structural body  100 A transmits a larger amount of light L. In other words, the light transmittance of structural body  100 A after the magnetic field is generated is high. This phenomenon is explained by the following mechanism. 
     The plurality of objects  40 A according to the present embodiment exhibit ferromagnetic properties. For that reason, the plurality of objects  40 A are magnetized by the magnetic field. Furthermore, magnetic force M 2  that is attracted to the electromagnet included in energy supply device  200 A acts on the plurality of objects  40 A. According to the present embodiment, since energy supply device  200 A is located on the negative side of the x-axis of structural body  100 A, the direction of magnetic force M 2  is the negative direction of the x-axis. According to this configuration, the plurality of objects  40 A respectively move within one space  30 A of the plurality of spaces  30 A. As a result of the plurality of objects  40 A moving, the plurality of objects  40 A are each located on the negative side of the x-axis in each of the plurality of spaces  30 A. 
     As a result, when structural body  100 A is viewed in the direction of travel of light L (the negative direction of the z-axis), the plurality of objects  40 A are positioned such that the plurality of objects  40 A overlap. Thus, as a result of the generation of magnetic force M 2  (i.e., as a result of changing of the state from (a) to (b) in  FIG. 4 ), the light incident on the plurality of objects  40 A out of light L is reduced. In other words, the light transmittance of structural body  100 A after magnetic force M 2  is generated is high. Accordingly, system  1000 A according to the present embodiment can be used as a light transmittance control device that controls the transmittance of light. 
     According to the configuration as described above, structural body  100 A exhibits the novel function of the plurality of objects  40 A, as a result of the plurality of objects  40 A moving. According to the present embodiment, as a result of the plurality of objects  40 A moving, it is possible to control the light transmission property that is one of the optical properties of structural body  100 A. In other words, according to the present embodiment, the novel function is the function of controlling the light transmission property of structural body  100 A. In addition, system  1000 A that includes structural body  100 A as described above can be used as a light transmittance control device that controls the light transmittance. 
     According to the present embodiment, at least one of the plurality of objects  40 A is present in each of the plurality of spaces  30 A. 
     According to this configuration, structural body  100 A is capable of including more objects  40 A. Therefore, before the magnetic field is generated, a larger amount of light L is absorbed and quenched by the plurality of objects  40 A. In other words, it is possible to further reduce the light transmittance of structural body  100 A before the magnetic field is generated. As a result, it is possible to further readily control the light transmission property that is one of the optical properties of structural body  100 A. 
     In addition, according to the present embodiment, when the first direction, the second direction, and the third direction are directions perpendicular to one another, the plurality of spaces  30 A are disposed along the first direction, the second direction, and the third direction. According to the present embodiment, for example, the x-axis direction is the first direction, the y-axis direction is the second direction, and the z-axis direction is the third direction. More specifically, among the plurality of spaces  30 A according to the present embodiment, three are arranged in the x-axis direction, two are arranged in the y-axis direction, and two are arranged in the z-axis direction. Thus, the plurality of spaces  30 A are arranged in the same manner as the plurality of spaces  30  according to Embodiment 1. 
     According to this configuration, it is possible to arrange the plurality of spaces  30 A of structural body  100 A so as to overlap in the first direction, the second direction, and the third direction. Accordingly, structural body  100 A is capable of including more objects  40 A. Therefore, before the magnetic field is generated, a larger amount of light L is absorbed and quenched by the plurality of objects  40 A. In other words, it is possible to further reduce the light transmittance of structural body  100 A before the magnetic field is generated. As a result, it is possible to further readily control the light transmission property that is one of the optical properties of structural body  100 A. 
     Embodiment 3 
     Although the plurality of objects  40  and  40 A are supplied with energy by energy supply devices  200  and  200 A in system  1000  and system  1000 A according to Embodiment 1 and Embodiment 2, the present invention is not limited to this example. In addition, Embodiment 3 is different from Embodiments 1 and 2 in that the three-dimensional net shaped body is an elastic body that deforms elastically. Furthermore, Embodiment 3 is different from Embodiments 1 and 2 in that structural body  100 B includes partition wall  32 B. It should be noted that, in Embodiment 3, the detailed description of the structural components common to Embodiment 1 or Embodiment 2 will be omitted. 
     Configuration 
     First, the configuration of structural product  300 B according to the present embodiment will be described with referenced to  FIG. 5A  and  FIG. 5B . 
       FIG. 5A  is a schematic diagram of structural product  300 B according to Embodiment 3. Structural product  300 B is a device that controls at least one of the optical property, the electrical conduction property, the thermal conductive property, or the fluid resistance property of structural body  100 B, as a result of the plurality of objects  40 B moving in the plurality of spaces  30 B. 
     Structural product  300 B according to the present embodiment is a device that includes structural body  100 B and contact point  50 . Contact point  50  includes contact point  51  and contact point  52  which are paired with each other. According to the present embodiment, structural product  300 B is an electronic device that controls the electrical conduction property of structural body  100 B. 
     Structural product  300 B according to the present embodiment can be used as a sensor for sensing the flow of current between contact point  51  and contact point  52  which are paired with each other. It should be noted that, according to the present embodiment, the combination of contact point  51  and contact point  52  facing each other across structural product  300 B is one pair. In other words, According to the present embodiment, there are three combinations of contact point  51  and contact point  52 . 
     For that reason, contact point  51  and contact point  52  which are paired with each other are electrically connected to a power supply device for applying a voltage and a current measurement device for measuring a current value. However, in  FIG. 5A , the power supply device and the current measurement device are not illustrated in order to prevent the diagram from being complicated. 
     In addition, structural body  100 B includes a three-dimensional net shaped body, a plurality of objects  40 B that are mobile objects, and partition wall  32 B that restricts the movement of the plurality of objects  40 B. The three-dimensional net shaped body includes a plurality of net lines  20 B. The plurality of net lines  20 B include a plurality of primary net lines  21 B and a plurality of secondary net lines  22 B. The plurality of spaces  30 B are regions sectioned by the plurality of net lines  20 B. 
     First, partition wall  32 B and the plurality of objects  40 B according to the present embodiment will be described. 
     As described above, structural body  100 B according to the present embodiment includes partition wall  32 B that restricts the movement of the plurality of objects  40 B. Partition wall  32 B is provided on a boundary plane. In addition, partition wall  32 B is provided on the entirety of one or more planes of the outermost planes. In other words, according to the present embodiment, partition wall  32 B is provided on the plane that is the interface between two adjacent spaces  30 B among the plurality of spaces  30 B, and on the entirety of one or more of the outermost planes. In addition, partition wall  32 B according to the present embodiment includes partition wall  32 Ba provided on the plane that is the interface between two adjacent spaces  30 B among the plurality of spaces  30 B, and partition wall  32 Bb provided on the entirety of one or more of the outermost planes. 
     In this manner, partition wall  32 B is provided to inhibit the plurality of objects  40 B from moving over two or more of the plurality of spaces  30 B. Accordingly, the plurality of objects  40 B are capable of staying within one of the plurality of spaces  30 B. Furthermore, it is possible to inhibit the plurality of objects  40 B from exiting the three-dimensional net shaped body. 
     The plurality of objects  40 B according to the present embodiment include a material that exhibits high electrical conductivity. More specifically, the surface of the plurality of objects  40 B is covered with copper which is a material that exhibits a high electrical conduction property. For that reason, the plurality of objects  40 B exhibit a high electrical conduction property. As a result of the plurality of objects  40 B being in contact with each other, a path for electrical conduction is generated. In addition, at least one of the plurality of objects  40 B is present in each of the plurality of spaces  30 B, in the same manner as Embodiment 2. 
     It should be noted that the plurality of objects  40 B according to the present embodiment each have a spherical shape in the same manner as Embodiment 1 and Embodiment 2, and the diameter of each of the plurality of objects  40 B is smaller than one side of each of the plurality of spaces  30 B which has a cubic shape. 
     Next, the three-dimensional net shaped body including the plurality of net lines  20 B will be described in detail with referenced to  FIG. 5B . 
       FIG. 5B  is an enlarged perspective view of space  30 B which is one of the plurality of spaces  30 B according to Embodiment 3. More specifically,  FIG. 5B  is an enlarged perspective view of space  30 B located on the most positive side of the x-axis among the plurality of spaces  30 B. For that reason, in one of the plurality of spaces  30 B illustrated in  FIG. 5B , partition wall  32 Bb is located on the positive side of the x-axis and partition wall  32 Ba is located on the negative side of the x-axis. 
     The three-dimensional net shaped body according to the present embodiment includes an elastomeric material that exhibits elasticity. Accordingly, the plurality of net lines  20 B according to the present embodiment include an elastomeric material that exhibits elasticity. According to the present embodiment, the plurality of net lines  20 B include a thermoplastic polyurethane resin material. However, the material included by the plurality of net lines  20 B is not limited to the above-described examples. 
     It should be noted that partition wall  32 B may include the same material as or a different material from that of the plurality of net lines  20 B. According to the present embodiment, partition wall  32 B includes the same material as that of the plurality of net lines  20 B. 
     The three-dimensional net shaped body including the plurality of net lines  20 B having the configuration as described above is an elastic body that deforms elastically. An elastic body has the property of changing the shape of the elastic body itself when a force is applied thereto, and restoring the original shape of the elastic body itself when the force is removed. In addition, as a result of the three-dimensional net shaped body deforming elastically, structural body  100 B and the plurality of spaces  30 B deform as well. 
     The plurality of net lines  20 B according to the present embodiment includes a plurality of primary net lines  21 B and a plurality of secondary net lines  22 B. The line thickness of the plurality of primary net lines  21 B is a larger than the line thickness of the plurality of secondary net lines  22 B. Lines extending along the y-axis and extending along the z-axis among the plurality of primary net lines  21 B are integrated with partition wall  32 B. In the same manner as above, lines extending along the z-axis among the plurality of secondary net lines  22 B are integrated with partition wall  32 B 
     Next, the behavior of structural product  300 B when force P is applied will be described. 
     Behavior at the Time of Force P Generation 
       FIG. 6  is a front view of structural product  300 B illustrated in  FIG. 5A . More specifically,  FIG. 6  is a front view of structural product  300 B illustrated in  FIG. 5A , when viewed in the negative direction of the y-axis. In  FIG. 6 , (a) indicates the front view of structural product  300 B before force P is generated, and (b) indicates the front view of structural product  300 B after force P is generated. 
     Force P that is a pressing force from outside is applied to structural product  300 B according to the present embodiment. According to the present embodiment, force P is generated in the directions to hold structural product  300 B in between. More specifically, the directions of force P are in the negative direction of the z-axis toward the top surface (the surface on the positive side of the z-axis) of structural product  300 B and in the positive direction of the z-axis toward the bottom surface (the surface on the negative side of the z-axis) of structural product  300 B. 
     As described above, the diameter of each of the plurality of objects  40 B is smaller than one side of each of the plurality of spaces  30 B which has a cubic shape. According to this configuration, as illustrated in (a) in  FIG. 6 , the plurality of objects  40 B are not in contact with each other before force P is generated. For that reason, the electric resistance value between contact point  51  and contact point  52  which are paired with each other is very high, and no current flows between contact point  51  and contact point  52  which are paired with each other. 
     On the other hand, as illustrated in (b) in  FIG. 6 , the plurality of objects  40 B are in contact with each other after force P is generated, and the plurality of objects  40 B are also in contact with contact point  51  and contact point  52 . According to this configuration, current flows between contact point  51  and contact point  52  which are paired with each other. This phenomenon is explained by the following mechanism. 
     The three-dimensional net shaped body according to the present embodiment is an elastic body that deforms elastically. For this reason, structural body  100 B deforms elastically according to the direction of force P. As a result, the shape of the plurality of spaces  30 B deforms. In other words, the shape of the plurality of spaces  30 B deforms such that the volume of the plurality of spaces  30 B is reduced. 
     The position of each of the plurality of objects  40 B in a corresponding one space  30 B among the plurality of spaces  30 B changes in accordance with the deforming of the plurality of spaces  30 B. More specifically, each of the plurality of objects  40 B moves in a corresponding one space  30 B among the plurality of spaces  30 B in accordance with the deforming of the plurality of spaces  30 B. As a result of the plurality of objects  40 B moving, the plurality of objects  40 B come into contact with each other. In addition, the plurality of objects  40 B are also in contact with contact point  51  and contact point  52 . As described above, the surface of the plurality of objects  40 B according to the present embodiment is covered by copper which exhibits high electrical conductivity, and thus a path for electrical conduction is generated. In other words, the electric resistance value between contact point  51  and contact point  52  which are paired with each other is very low, and thus current flows between contact point  51  and contact point  52  which are paired with each other. Accordingly, structural product  300 B that includes structural body  100 B can be used as a pressure sensor. 
     In addition, when force P is removed, the three-dimensional net shaped body deforms elastically, and structural product  300 B returns to the state in which the plurality of objects  40 B illustrated in (a) in  FIG. 6  are not in contact with each other. In other words, according to the presence or absence of force P, it is possible to control whether current flows between contact point  51  and contact point  52  which are paired with each other. Thus, structural product  300 B can also be used as a switching . 
     To summarize the above, structural product  300 B according to the present embodiment includes structural body  100 B. 
     According to this configuration, as a result of the plurality of objects  40 B moving, structural product  300 B is capable of exerting a novel function of structural body  100 B. 
     In addition, structural product  300 B controls at least one of the optical property, the electrical conduction property, the thermal conductive property, or the fluid resistance property of structural body  100 B, as a result of the plurality of objects  40 B moving. According to the present embodiment, structural product  300 B controls the electrical conduction property of structural body  100 B. In other words, the novel function of structural body  100 B is the function of controlling the electrical conduction property of structural body  100 B. 
     According to this configuration, structural product  300 B can be used as a sensor for sensing the flow of current. In addition, structural product  300 B can also be used as a switching element. 
     Meanwhile, structural product  300 B can be used for different applications than the above-described sensor or switching element, by changing the property to be controlled. 
     In addition, structural product  300 B according to the present embodiment is an electronic device. 
     According to this configuration, structural product  300 B can be used as an electrical device that can be readily integrated into other devices. 
     In addition, the three-dimensional net shaped body according to the present embodiment is an elastic body that deforms elastically. 
     According to this configuration, the shape of the three-dimensional net shaped body changes as a result of force P being applied to the three-dimensional net shaped body, and thus the plurality of objects  40 B can be readily moved. 
     In addition, as described above, structural body  100 B according to the present embodiment includes partition wall  32 B that restricts the movement of the plurality of objects  40 B, and is provided on the boundary planes that define the plurality of spaces  30 B. 
     In addition, in structural body  100 B according to the present embodiment, one or more of the boundary planes are included in outermost planes located outermost of the three-dimensional net shaped body, and partition wall  32 B is provided on the entirety of one or more of the outermost planes. 
     According to the above-described configuration, the plurality of objects  40 B are inhibited from moving over two or more of the plurality of spaces  30 B. In addition, as a result of the above, the plurality of objects  40 B are capable of staying within one of the plurality of spaces  30 B. Furthermore, it is possible to inhibit the plurality of objects  40 B from exiting the three-dimensional net shaped body. In addition, as indicted in the present embodiment, when the three-dimensional net shaped body is an elastic body, it is possible to inhibit structural body  100 B from being broken by force P, by providing structural body  100 B with partition wall  32 B. 
     Variation of Embodiment 3 
     Here, a variation of Embodiment 3 will be described. It should be noted that, in the present variation, the detailed description of the structural components common to Embodiment 3 will be omitted. 
     Although the configuration in which the diameter of each of the plurality of objects  40 B is smaller than one side of each of the plurality of spaces  30 B which has a cubic shape has been described in Embodiment 3, the present invention is not limited to this example. According to the present variation, the diameter of each of the plurality of objects  40 B is larger than one side of each of the plurality of spaces  30 B which has a cubic shape. 
     In other words, according to the present variation, the plurality of objects  40 B present in different two or more of the plurality of spaces  30 B are in contact with each other. More specifically, even when force P that is a pressing force from outside is not applied to structural product  300 B, the plurality of objects  40 B are respectively in contact with each other in advance, and current flows between contact point  51  and contact point  52  which are paired with each other. 
     In addition, according to the present variation, force P is generated in the direction to stretch structural product  300 B. In other words, the directions of force P are in the positive direction of the z-axis with respect to the top surface (the surface on the positive side of the z-axis) of structural product  300 B and in the negative direction of the z-axis with respect to the bottom surface (the surface on the negative side of the z-axis) of structural product  300 B. 
     According to the present variation, when force P is applied to structural product  300 B, structural body  100 B deforms elastically according to the direction of force P. As a result, the shape of the plurality of spaces  30 B deforms. In other words, the shape of the plurality of spaces  30 B deforms such that the volume of the plurality of spaces  30 B is increased. 
     The position of each of the plurality of objects  40 B in a corresponding one space  30 B among the plurality of spaces  30 B changes in accordance with the deforming of the plurality of spaces  30 B. More specifically, each of the plurality of objects  40 B moves in a corresponding one space  30 B among the plurality of spaces  30 B in accordance with the deforming of the plurality of spaces  30 B. As a result of the plurality of objects  40 B moving, each of the plurality of objects  40 B is no longer in contact with each other. For that reason, the electric resistance value between contact point  51  and contact point  52  which are paired with each other is very high, and thus current does not flow between contact point  51  and contact point  52  which are paired with each other. Accordingly, structural product  300 B that includes structural body  100 B according to the present variation can be used as a pressure sensor. 
     To summarize the above, in structural product  300 B according to the present variation, the plurality of objects  40 B respectively present in different two or more of the plurality of spaces  30 B are in contact with each other. 
     According to this configuration, as a result of the plurality of objects  40 B moving, it is possible to control whether the plurality of objects  40 B come into contact with each other. As a result, it is possible to exert the novel function of structural body  100 B. 
     Others 
     Although the structural body, system, and structural product according to the present invention have been described based on the above-described embodiment, the present invention is not limited to the above-described embodiments. 
     According to the embodiments, the plurality of net lines includes a plurality of primary net lines having a larger line thickness and a plurality of secondary net lines having a smaller line thickness. However, the plurality of net lines are not limited to this example. All of the plurality of net lines may have the same line thickness. In other words, the primary net line and the secondary net line may be the same line. The cross-section shape of the plurality of net lines may be any shape. For example, the cross-section shape of the plurality of net lines may be a circular or polygonal shape. Furthermore, the cross-section shape of the plurality of net lines may be a circular or polygonal shape with protrusions (e.g., star-shaped, gear-shaped, etc.). In particular, when the shape is that provided with protrusions, restricting the movement of the plurality of objects is facilitated. 
     In addition, although the plurality of primary net lines and the plurality of secondary net lines included in the plurality of net lines are lines extending along the x-axis, the y-axis, or the z axis according to the embodiments, the plurality of primary net lines and the plurality of secondary net lines are not limited to this example. For example, the plurality of primary net lines and the plurality of secondary net lines may be lines not parallel to any of the x-axis, the y-axis, or the z-axis. In other words, the plurality of primary net lines and the plurality of secondary net lines may be lines that extend in arbitrary directions. 
     It should be noted that, although the configuration in which the three-dimensional net shaped body exhibits a high rigidity has been described in Embodiments 1 and 2, the configuration of the three-dimensional net shaped body is not limited to this example. For example, the three-dimensional net shaped body according to Embodiment 1 may be an elastic body that deforms elastically, as with the three-dimensional net shaped body according to Embodiment 3. Furthermore, the three-dimensional net shaped body according to Embodiment 1 may include a portion that exhibits a high rigidity and another portion that is an elastic body. In other words, a portion of the plurality of net lines included in the three-dimensional net shaped body may exhibit a high rigidity and another portion of the plurality of net lines may be an elastic body. In the case of the three-dimensional net shaped body in which a portion that is highly rigid and a portion that is an elastic body are combined, when the magnetic field described in Embodiment 1 is generated, the structural body is capable of exerting the function of elastically deforming only the portion that is an elastic body. 
     In addition, although the boundary plane and the outermost plane are planar according to the embodiments, the boundary plane and the outermost plane may be curved. 
     Although the energy supply device is a device that includes an electromagnet and generates a magnetic field according to Embodiment 1 and Embodiment 2, the energy supply device is not limited to this example. The energy supply device may generate thermal energy, optical energy, chemical energy, mechanical energy, or the like, or a combination of them. 
     In addition, although the plurality of objects move as a result of being supplied with energy generated by the energy supply device according to Embodiment 1 and Embodiment 2, the present invention is not limited to this example. For example, the plurality of objects may move according to gravity, as a result of the structural body being tilted with respect to a horizontal plane. 
     It should be noted that, although iron or copper is used for the plurality of objects according to Embodiments 1, 2, and 3, the plurality of objects are not limited to this example. The material used for the plurality of objects may be selected according to energy that moves the plurality of objects. 
     In addition, the plurality of objects may include different materials. In other words, for example, one of the plurality of objects may include the first material, and different one of the plurality of objects from the one of the plurality of objects may include the second material that is different from the first material. More specifically, one of the plurality of objects may include iron in the same manner as Embodiment 1, and different one of the plurality of objects from the one of the plurality of objects may include cobalt. 
     According to Embodiment 2, the type of material having high light absorptivity is selected according to the wavelength that light L contains. For example, when light L is infrared light, the material having high light absorptivity is selected from among the materials that absorb infrared light. In addition, for example, when light L is ultraviolet light, the material having high light absorptivity is selected from among the materials that absorb ultraviolet light. 
     Although the configuration in which the light transmission property that is one of the optical properties of the structural body is controlled has been described in Embodiment 2, the present invention is not limited to this. For example, the light reflection property or the light scattering property may be controlled. 
     Although the configuration in which the electrical conduction property of the structural body is controlled has been described in Embodiment 3, the present invention is not limited to this. For example, the thermal conductive property may be controlled. In this case, the plurality of objects may include a material that exhibits high thermal conductivity. For example, a metallic material or the like may be used as the material that exhibits high thermal conductivity. According to this configuration, as a result of the plurality of objects being in contact with each other, a path for thermal conduction is generated. 
     The following describes the case where the fluid resistance property among the properties of the structural body is controlled. The fluid is water, for example. In such a case, for example, a configuration in which the shape of the opening portion is circular, the shape of the plurality of objects is spherical, and the diameter of each of the plurality of objects is larger than the diameter of the circular shape of the opening portion is used. According to this configuration, when the plurality of objects cover the opening portion, the fluid cannot move over two or more of the plurality of spaces through the opening portion. On the other hand, when the plurality of objects move and do not cover the opening portion, the fluid can move over two or more of the plurality of spaces. In this manner, it is possible to switch between covering and not covering the opening portion by the plurality of objects, according to the movement of the plurality of objects. As a result, it is possible to control the fluid resistance property of the structural body. 
     It should be noted that the structural body may emit sound as a result of the plurality of objects moving through the plurality of spaces. The structural body may emit a sound by the plurality of objects coming into contact with the plurality of net lines as a result of the plurality of objects moving. In this manner, it is possible to recognize, by the sound, that the plurality of objects have moved. 
     In addition, although the three-dimensional net shaped body and the plurality of net lines include an ABS resin material or a thermoplastic polyurethane resin material according to the embodiments, the materials of the three-dimensional net shaped body and the plurality of net lines are not limited to these examples. For example, the three-dimensional net shaped body and the plurality of net lines may include a material such as a nylon resin material, a poly-lactic acid (PLA) resin material, a polycarbonate resin material, a polycarbonate/ABS alloy resin material, a poly phenyl sulfone (PPSF/PPSU) based resin material, an acrylate-styrene-acrylonitrile (ASA) based resin material, a poly ether ether ketone (PEEK) based resin material, a poly ether imide (PEI) resin material, an epoxy resin material, a polypropylene resin material, a vinyl chloride resin material, a Teflon (registered trademark) resin material, a polyethylene terephthalate resin material, or the like. In addition, not limited to the above-described materials, the three-dimensional net shaped body and the plurality of net lines may include a material such as an engineering plastic or a super engineering plastic. The materials that the three-dimensional net shaped body and the plurality of net lines include are selected according to the application of the structural body. 
     As described in Embodiment 1, the three-dimensional net shaped body was manufactured by the material extrusion method. However, the method of manufacturing the three-dimensional net shaped body is not limited to this example. For example, the three-dimensional net shaped body can be manufactured by the liquid tank photopolymerization method. 
     The liquid tank photopolymerization method is conducted according to the following procedure. The material that the three-dimensional net shaped body includes has fluidity. The material that the three-dimensional net shaped body includes is exposed to a predetermined stimulus so as to be a three-dimensional manufacturing target that is desired to be manufactured. As a result, the material that the three-dimensional net shaped body includes becomes a cured layer. The three-dimensional manufacturing target that is desired is obtained by stacking the cured layers. For example, an ultraviolet-curing resin can be used as the material that the three-dimensional net shaped body includes, and ultraviolet rays can be used as the predetermined stimulus. 
     In addition, although the structural body has been manufactured by arranging the plurality of objects to be present in the plurality of spaces in the middle of the manufacturing of the three-dimensional net shaped body, the manufacturing of the structural body is not limited to this example. For example, when the three-dimensional net shaped body is an elastic body that deforms elastically as described in Embodiment 3, the plurality of objects may be inserted through the opening portion by elastically deforming the shape of the opening portion after the three-dimensional net shaped body is manufactured. In addition, the plurality of objects can be manufactured by a 3D printer using a material extrusion method, in the same manner as the manufacturing of the three-dimensional net shaped body. In this case, when the plurality of objects and the three-dimensional net shaped body include the same material, filaments of the same material can be used. On the other hand, when the plurality of objects and the three-dimensional net shaped body include different materials, filaments of different materials can be respectively used. 
     In addition, for the manufacturing of the plurality of objects, the liquid tank photopolymerization method, the material injection method, the binder injection method, powder bed melt bonding method, or the like can be used, in the same manner as the manufacturing of the three-dimensional net shaped body. 
     It should be noted that, although the structural body is mounted on the mounting base according to Embodiments 1 and 2, the present invention is not limited to this example. The structural body may be placed in any manner as long as the structural body is capable of receiving energy supplied by the energy supply device. In addition, the system need not necessarily include the mounting base and the column support. 
     Additionally, embodiments arrived at by those skilled in the art making modifications to the above embodiments, as well as embodiments arrived at by combining various structural components and functions described in the above embodiments without materially departing from the novel teachings and advantages of the present invention are intended to be included within the scope of the present invention. 
     REFERENCE SIGNS LIST 
     
         
           10  three-dimensional net shaped body 
           20  net line 
           30  space 
           31  boundary plane 
           32 B partition wall 
           40  object 
           100  structural body 
           200  energy supply device 
           300 B structural product 
           1000  system