Patent Publication Number: US-2023146386-A1

Title: System and method for building layout

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 63/277,312 filed 9 Nov. 2021, the entire contents of which are herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates a system, device and method for facilitating the layout of a building and/or the sites of components, fixtures and features within a building. 
     BACKGROUND OF THE INVENTION 
     Foundation layout for the construction of a building can be a time consuming process. It is imperative that batter boards that mark the heights of a foundation are placed accurately and that the building edge projections are accurately marked on the batter boards to enable the boundaries of the foundation to be followed during construction of the foundation. Setting these heights and edges can be a painstaking process with many iterations. What is required is an improved system and method that can increase the accuracy and/or efficiency of the building layout process. 
     SUMMARY OF ONE EMBODIMENT OF THE INVENTION 
     Advantages of One or More Embodiments of the Present Invention 
     The various embodiments of the present invention may, but do not necessarily, achieve one or more of the following advantages: 
     the ability to quickly mark out a building foundation; 
     provide improved accuracy in building foundation layout; 
     reduce the number of people required to set out a building foundation; 
     provide an ability to mark out installation features within a building; and 
     provide an automated device that can be controlled into positions for marking out features of a building. 
     These and other advantages may be realized by reference to the remaining portions of the specification, claims, and abstract. 
     BRIEF DESCRIPTION OF ONE EMBODIMENT OF THE PRESENT INVENTION 
     In one aspect of the present invention, there is provided a method for building foundation layout. The method may comprise locating at least one moveable device onto a vertical batter board and providing a first guidance signal from a control unit to the at least one moveable device to move the at least one moveable device to indicate a height of a top of a building foundation. The at least one moveable device may be located onto a horizontal batter board placed on the vertical batter board in alignment with the indicated height of the top of the building foundation. A second guidance signal to the at least one moveable device may move the at least one moveable device to indicate a position on the horizontal batter board where an extension of a building edge intersects the horizontal batter board. 
     In one aspect of the present invention, there is provided a moveable device for use in laying out a building foundation. The moveable device may comprise one or more guides for locating the moveable device on a batter board. A motor may drive the one or more guides to cause the moveable device to move along the batter board. At least one control unit may receive guidance signals and control the motor in response to the guidance signals. 
     In one aspect of the present invention, there is provided a system for building foundation layout. The system may comprise a control unit and one or more moveable position indicating devices that can be deployed onto batter boards located on a building site. The moveable position indicating devices may be located onto a vertical batter board and receive a first guidance signal from the control unit that moves the device along the vertical batter board to a position that indicates a height of a top of a building foundation. The device may be located onto a horizontal batter board placed on the vertical batter board in alignment with the indicated height of the top of the building foundation and receive a second guidance signal from the control unit. The second guidance signal moves the device along the horizontal batter board in response to the second guidance signal to a position on the horizontal batter board that indicates where an extension of a building edge intersects the horizontal batter board. 
     In one aspect of the present invention, there is provided a moveable device for use in laying out a building foundation. The moveable device may comprise guide means, motor means and signal means. The guide means may be for locating the moveable device on a batter board. The motor means may be for driving the guide means to cause the moveable device to move along the batter board. The signal means may be for receiving guidance signals and controlling the motor means in response to the guidance signals. 
     The above description sets forth, rather broadly, a summary of one embodiment of the present invention so that the detailed description that follows may be better understood and contributions of the present invention to the art may be better appreciated. Some of the embodiments of the present invention may not include all of the features or characteristics listed in the above summary. There are, of course, additional features of the invention that will be described below and will form the subject matter of claims. In this respect, before explaining at least one preferred embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    substantially depicts a schematic of a system for building layout in accordance with an embodiment of the present disclosure; 
         FIG.  2    substantially depicts a specific embodiment of the system of  FIG.  1   ; 
         FIG.  3    substantially depicts a building layout method; 
         FIG.  4    substantially depicts a pointcloud representation of a building site; 
         FIG.  5    substantially depicts a digital representation of a building; 
         FIG.  6    substantially depicts the digital building overlaid on the pointcloud representation; 
         FIG.  7    substantially depicts a method step of indicating corners of a building on a building site; 
         FIG.  8    substantially depicts a method step of locating vertical batter boards adjacent the proposed building corners of the building site; 
         FIG.  9    substantially depicts a method using the system of  FIG.  1    to indicate the height of the building foundation on the vertical batter boards; 
         FIG.  10    substantially depicts a method step of locating horizontal batter boards to mark the height of a building foundation; 
         FIG.  11    substantially depicts a method step of marking building wall projections onto the horizontal batter boards; 
         FIG.  12    substantially depicts a perspective view of an actuator for traversing batter boards; 
         FIG.  13    substantially depicts a side view of the actuator of  FIG.  12    with a near-side removed to show internal components of the actuator; 
         FIG.  14    substantially depicts a front view of the actuator of  FIG.  12    with near-side components removed to show internal components of the actuator; 
         FIG.  15    substantially depicts a perspective view of an alternative embodiment of an actuator featuring bracket for mounting a marking device; 
         FIG.  16    substantially depicts a building site scan that can capture errors in the placement of foundation form boards; 
         FIG.  17    substantially depicts a display of a graphic user interface that enables a building location to be shifted on a building site; and 
         FIG.  18    substantially depicts indicating positions of features within the perimeter of form boards. 
     
    
    
     DESCRIPTION OF CERTAIN EMBODIMENTS OF THE PRESENT INVENTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part of this application. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     In general, the concept to be described uses a scanning system to generate an accurate point cloud representation of a building pad or closed in building. The scanning system may be a LIDAR scanning array, camera and photogrammetry software, or a combination of such systems. A digital building design can be overlaid and merged with the point cloud and used to calculate the position of each corner of the building foundations. A laser pointer or augmented reality application at the foundation site, e.g. as part of the LiDAR scanning array, can be used to indicate the physical location of the corners of the building on the building pad. Vertical batter boards can be accurately placed in the vicinity of the corners. Once the vertical batter boards are placed, a re-scan of the building site takes place and the resulting point cloud including the vertical batter boards is synced with the digital design, so that the vertical batter boards are also represented in this merged model. Controlled moveable devices are then placed on each vertical batter board and directed by guidance instructions to move to a point where a level plane indicating the top of the foundation is indicated. Then, horizontal batter boards will be attached to the vertical boards at the level indicated. Next the same type of moveable device will be mounted on the horizontal batter boards and directed to move into the location that represents locations where the extension of each building edge meets the batter board. The use of controlled devices to indicate and accurately locate the top of the building foundation and the points where the extension of each wall edge meets the horizontal batter boards will speed and simplify the layout process and deliver a greater degree of accuracy and certainty. The same or a similar process can be used to layout interior walls and locations of other elements, such as mechanical, plumbing, electrical and media fixtures and lines. Additionally, having a digital representation of the existing physical amenities can provide a platform for use by additional autonomous equipment during construction and/or the operator of the building once the construction phase is completed. 
     The process described above utilizes a scanning system resulting in a static pointcloud representation of a building pad. Alternatively, the system may utilize dynamic sensor inputs from multiple live sensors distributed across the building pad. In this embodiment, when the batter boards are placed, the batter boards can be almost instantly merged into the model due to the live scanning by the sensors. 
       FIG.  1    shows the components of a system for marking a building layout in accordance with an embodiment of the invention. The system  100  includes a control unit  110  containing control electronics, communications modules, power electronics and ancillary components for controlling the other components of the system. The control unit may include a power port and/or power cable for connecting to a source of mains power. Alternatively or in addition, the control box may include an internal battery. The battery may be rechargeable, including solar rechargeable. Within the control unit  110  there may be a transformer that converts mains power to 24V DC power. DC power may be distributed from the control unit  110  to other powered elements of the system as will be described below. 
     The control electronics may include at least one processor and at least one memory operatively associated with the at least one processor. The at least one memory may include at least one read only memory (ROM) for storing programs, apps, code, data, etc. The at least one memory may also include at least one random access memory (RAM) for use in executing programs, apps, code, etc. The control unit  110  may include connections to the other components of the system. The connections may include physical electrical connections, data connections, wireless connections (e.g. via the communications modules) etc. In one embodiment, the control unit  110  may be a mobile computing device, such as a mobile telephone, laptop, tablet, iPad, etc. 
     The system  100  further includes a scanning system  120 . As mentioned above, the scanning system may utilize at least one LIDAR scanner, photogrammetry or a combination of such systems. In a LIDAR embodiment, the LiDAR scanner is able to transmit low powered laser signals across an area. Reflected signals can be received into the LiDAR scanner  120  and transmitted to the control unit  110  for processing into a 3-D representation of an area. The LiDAR scanner  120  may be connected to the control unit  110  by cabling  126 , including a data cable (e.g. ethernet) and/or a power cable. Power and signals may be conveyed between the control unit  110  and the LiDAR scanner  120  through this cabling. In alternative embodiments, the LiDAR scanner  120  may include its own power supply, e.g. battery power or connection to mains, and may communicate with the control unit  120  through wireless protocols such as Bluetooth or WiFi, or other wireless methods as commonly applied to IoT devices. In one embodiment, the scanning system may be incorporated into the computing device. For example, a mobile device such as a tablet, iPad, mobile telephone etc. may be utilize its camera functions to perform photogrammetry at the building site. 
     The system  100  further includes at least one marking pointer  130 . The marking pointer may be a laser pointer, an augmented reality application, or other device(s) that allow specific locations on the building pad to be accurately indicated. The system  100  further includes at least one moveable device  140  disposed on a vertical batter board  148 . The moveable device  140  may include a motor, such as a stepper motor or servo motor, a power source such as a battery or power port for external power connection, and a communications module for receiving control signals from the control unit  110 . The device  140  may be configured for wired or wireless communications with the control unit  140 . Specific embodiments of the moveable device  140  will be described in detail below. The device  140  may include at least one fiduciary marker that can be used to provide a physical reference point and an indicator. The indicator may include a visible indicator, such as a beacon or similar light. The indicator may also include an audible indicator, such as an alarm that is capable of producing different tones or sounds to indicate a number of different statuses. 
     A specific embodiment of the system  100  is depicted in  FIG.  2   . In  FIG.  2   , the control unit  210  may include a mobile device such as a tablet or iPad supported on a stand  212 . The mobile device  210  may have camera features and software that are able to perform photogrammetry by taking multiple photographs across the site and constructing a digital model of the site. The mobile device  210  may also be programmed with augmented reality software that is able to provide guidance in place of a laser pointer for indicating the corners of buildings. The mobile device  210  may be able to communicate with the moveable device  240 . 
     The system of  FIG.  1    may be used at various locations of the physical site to create a scaled point cloud of the location, which is then merged with a digital building design. Multiple scans or digital photographs are taken across the site and then merged into a single point cloud that is scaled and represents the building site digitally. Typically, only one scanner or camera device is needed, though additional scanners and operators could be used to speed the process. Only one laser pointer or augmented reality device would also be needed, though more could be used to speed the process. The scanners would be placed or held at various locations around the physical site to accurately capture the physical features of the site (known as reality capture) and then required locations are calculated. Then the laser pointer or augmented reality device would be used to indicate approximate locations of building features (foundation corners, etc.) so that batter boards can be placed in the correct adjacent locations. Precise indication of the corners is not essential at this stage. Once vertical batter boards are placed, the area is re-scanned and the new scan is merged with the digital building plans again so that the vertical batter boards are also shown in the blended model. Then the actuator device is placed on the vertical batter board and it moves along it so as to indicate the exact location of the level at the top of the foundation so that horizontal batter boards can be placed at that level. Once those are placed, the actuator device is set up on the horizontal batter boards so the locations where the extension of each building edge meets the horizontal batter board can be indicated. 
       FIG.  3    shows a flowchart  300  of a building layout method in accordance with an embodiment of the invention. At step  302 , a scan of a building pad is undertaken. In one embodiment, the scan may be performed using LIDAR scanner(s) to generate a pointcloud representation of the building pad. In another embodiment, sensors may be placed at appropriate locations around the building pad. At step  304 , a digital building model can be merged with the pointcloud data or live sensor data to create a digital building layout. At step  306 , the digital building layout is utilized to indicate the corners on the physical building site, e.g. utilizing a laser pointer(s) or augmented reality. Vertical batter boards can be placed adjacent the corners on the building site (step  308 ) and the building site re-scanned to incorporate the vertical board placement into the digital building layout (step  310 ). Third party applications (potentially blending LiDAR and photogrammetry capabilities) may be used to generate and update the point cloud representation of the building site, which is merged with the digital design of the building to then drive the layout process. Fiducial markers may be used to assist in scaling size/distance in the generation/updating of the point cloud representation of the building site, to increase accuracy and precision. 
     At step  312 , the moveable actuator device  140  is placed onto a vertical batter board and controlled, using the control unit  110 / 210  in conjunction with the digital building layout data, to locate and mark the top of foundation intersections on vertical batter boards. This step can be repeated for each of the vertical batter boards on the building site. At step  314 , horizontal batter boards can be placed on the vertical boards at the heights marked in step  312 . The device  140  can then be placed on the horizontal batter boards and controlled to indicate where the foundation edge extension intersection the horizontal batter boards (step  316 ). 
     Once the process has begun and a digital representation of the building site has been created, if the sensors dispersed on the site need to be moved, they do not need to be replaced in the same locations, as the point cloud can be automatically registered based on the locations of landmarks/features in the scene. 
     The locations of batter boards and other components, such as foundation form boards once they have been placed, can be checked for accuracy and adherence to the plan, using the same sensors and software systems that were used to create and drive the layout.  FIG.  16    shows a rescan  1600  of a building site once batter boards  1610 , string lines  1612 , form boards  1614  and any other layout features have been placed. In this example, a comparison of the scan  1600  to a digital building layout reveals that the board  1620  has been placed on the wrong side of the string line  1622 . Rescanning the building site once form boards and other elements are placed and comparing the live site to the digital plans can catch errors ahead of concrete being poured and allow any necessary adjustments and rectifications to be made. 
       FIG.  4    shows an example of a pointcloud representation  400  of an area that may be produced from the scanning system  120 .  FIG.  5    shows a digital 3-D representation  500  of a building design.  FIG.  6    shows an overlay  600  in which the digital building design  500  has been overlaid and merged with the pointcloud representation  400 . Using this overlay, the physical location of elements of the building design can be calculated. In particular, the corners of the building required for the foundations can be calculated as a series of data points, e.g. as GPS coordinates, latitude/longitude, as points at calculated locations relative to other visible features in the physical area, etc. At the building site, the control unit can communicate the coordinates of the corners to the laser pointer and control the laser pointers to point at the corners of the building  710  on the ground  720  ( FIG.  7   ). An augmented reality, e.g. displayed on a tablet, can also be used to indicate the corners  710 . Pinpoint precision of the building corners is not essential at this stage. Adjacent each corner  710 , vertical batter boards may be installed. As shown in  FIG.  8   , each corner  710  includes four vertical batter boards. A first set of two batter boards  802 ,  804  are located either side of the corner in a first direction (e.g. the x-coordinate) and a second set of batter boards  806 ,  808  are located either side of the corner in an orthogonal direction to the first direction (e.g. the y-coordinate). Each set of batter boards are located outwards of the building footprint  820  on the ground  720  at the building site. Once the vertical boards are placed, the site may be re-scanned and the vertical boards incorporated into the digital building model. In one embodiment, fiducial marker codes specific to each batter board can be generated and associated with each vertical/horizontal batter board. A sticker or similar marker may be placed on the batter board with that code on it to be read by the sensor, so that that batter board can be correctly identified and correlated to the correct location in the digital model. For example, each of the vertical batter boards can be assigned a number, V1-V16, and a specific fiducial code, similar to a QR code can be printed on a sticker and applied to the corresponding batter board. Then the sensor can read that code on the batter board and the software can select the correct batter board in the model and direct the actuator device to indicate the correct location representing top of foundation level as it intersects the vertical batter board. The same process can be repeated for horizontal batter boards and the locations where building edge extensions intersect the batter boards. 
     A method  900  for using the system  100  including control unit  110  and moveable actuators  140  to indicate the top of a building foundation will now be described with reference to  FIG.  9   . The method  900  assumes that vertical batter boards are in place on site as shown in  FIG.  8    and have been scanned into the digital building model. The method  700  also relates specifically to the embodiment of the system  100  shown in  FIG.  2    in which a sensor, such as the camera of tablet  210 , is able to sense the position of and communicate with the moveable actuator device. The method starts at  902  by placing the sensor in a location where it has a close up isolated view of vertical batter board x of 16 (the number 16 assumes a generally rectangular building pad with four vertical boards at each of four corners. A greater or lesser number of corners and vertical boards may be deployed. At step  904 , an actuator device  140  is placed on a vertical batter board, e.g. board  802 , so that the sensor has an unobstructed view of the device  140 . At  906 , the sensor scans for any fiducial or reference marker on the batter board and/or on the actuator device. If no correlation can be found  908  then the sensor indicates an error to the operator  910  to enable any adjustments to be made. Once a fiducial is found the actuator may be correlated to a location on the batter board  912 . The sensor software can then scale and merge the live sensor image with the digital model  914 .  FIG.  9    of original patent application # 906  the fiducial marker mentioned can be used to indicate the specific batter board that is being scanned, or there may be other methods of indicating that as well, such as QR codes, bar codes and/or sequential numbering. There may also be a fiducial marker placed on the actuator device to assist with distance/size scaling in the scanner&#39;s field of view, and to assist with the moving of the actuator into the correct location to indicate the desired junction point or location (junction of top of foundation with vertical batter board, or junction with extension of building/foundation edge with horizontal batter board, or location of other building component, such as drain lines or electrical conduit) 
     At step  916 , the sensor identifies the location of the actuator on the batter board. Software that is able to read the digital building model and the current position of the actuator then directs the movement of the actuator along the batter board until the actuator is indicating the location of the intersection desired (step  918 ). For a vertical batter board, the actuator will be moved up/down the batter board until the actuator marks the point on the batter board that intersects with the top of the foundation. The actuator and/or sensor may activate a signal  920  (audible, visible or both) to indicate that the location cycle of the actuator is complete. The user, e.g. builder, contractor, etc., marks the desired location on the board  922 , or alternatively the actuator may carry a marking system and mark the location without manual input. For a vertical board, a level may be used to mark the foundation height across the width of the board. The user then moves the sensor and actuator onto the next batter board  924  and the process is repeated. 
     Once the vertical batter boards have all been marked, horizontal batter boards can be placed across that brace each pair of batter boards. The top of the horizontal batter boards mark the height of the top of the building foundation, e.g. for a subsequent concrete pour or other creation of the building foundation.  FIG.  10    shows the building site after placement of horizontal batter boards  1002  at each corner. 
     The actuator can be placed on the horizontal boards  1002  and the sensor placed in view of the actuator to enable guidance of the actuator on the horizontal boards. The method  900  can then be repeated on the horizontal boards to locate and mark the corner projections  1102 ,  1104  onto each of the horizontal batter boards  802 ,  804  ( FIG.  11   ). That is, the actuator can receive guidance commands from the control sensor that cause the actuator to move into the location that represents the location where the extension  1106 ,  1108  of each building edge  1112 ,  1114  meets the respective horizontal batter board  1002 ,  1004 . 
       FIGS.  12  to  14    show an embodiment of an actuator that can be utilized in the systems and methods of the invention as described herein. The actuator  1200  includes a body  1210  that is the approximate width of a batter board  1250  (e.g. 2 inch), though the width may be adjustable to fit on different sized batter boards such as 2×4 inch, 1×4 inch, metal stakes, or other configurations. At each edge of the body  1210  there is a guide wheel  1220  supported in a flange mount  1212  that is angled outward relative to the body  1210  such that the wheels  1220  are similarly angled relative to the body  1210 . The guide wheels  1220  are spaced apart by approximately the width of the batter board  1250  at the axles, but taper inwards towards the batter board  1250  such that the wheels are required to be flexed outwards to receive the batter board  1250 . The resilience in the mounts then cause the guide wheels to engage the sides of the of the batter board  1250  such that rotation of the guide wheels  1220  cause the actuator to traverse the batter board. The guide wheels are stiff enough to clamp onto the batter board and maintain position and grip with tension. 
     The body  1210  supports a motor  1224 , such as a servo motor or stepper motor, that is operatively connected to the guide wheels. Signal units  1230 ,  1232  include communications modules that are able to communicate with the main control unit  110  of the system  100  ( FIG.  1   ). The signal units  1230 ,  1232  are able to receive guidance commands from the main control unit and in response, operate the motor  1224  to turn the guide wheels  1220 , thereby causing the actuator to traverse the batter board. One of the signal units ( 1232 ) stores programs to run the drivers i.e. interprets the commands sent by the main control unit. The other signal unit ( 1230 ) converts the voltage received from the first control unit ( 1232 ) into pulses that rotate the motor shaft. 
       FIG.  13    shows a side view of the actuator  1200  with one guide wheel  1220  removed to show the internal connection between the guide wheel  1220  and the motor  1224 . The motor includes a drive axle  1226  that engages a drive gear  1228 . The drive gear  1228  engages a cog  1242 . Operation of the motor turns the drive axle  1226 , the drive gear  1228  and the cog  1242 . 
       FIG.  14    is a front view of the actuator with the motor  1224  and signal units  1230 ,  1232  removed.  FIG.  14    shows that the guide wheels  1220  are each operatively connected to the cog  1242  by articulated axles  1244 . The articulated axles  1244  include a bend joint  1246  between the centrally mounted cog  1242  and the angled mounts  1212  that allows for the angle between the mounts  1212  and the cog  1242 .  FIG.  14    further shows a set of contact rollers  1260  supported within the body of the actuator that space the body of the actuator from the batter board  1250  and allow free rolling of the actuator along the batter board. 
     While the embodiment of  FIGS.  12 - 14    uses guide wheels  1220 , other forms of guiding and movement systems may be used to both locate the actuator onto the batter board and to provide movement of the actuator along the batter board. In one alternative embodiment, a caterpillar drive system may be utilized. In a further alternative embodiment, a system of one or more rollers may be used. 
     An embodiment of an actuator  1300  is depicted in  FIG.  15   . The actuator  1300  includes a mounting bracket  1302  that enables a marking apparatus to be mounted onto the actuator. The marking apparatus may be automatically driven or may be manually operated once the actuator indicates a required position on a board to be marked. The marking apparatus may be used to indicate the desired location and purpose/associated component of location indication at each step. Types of marking apparatus may include, without limitation, inkjet marking (including text), laser etching or engraving (including text), airbrush marking (including text), and/or placing a physical object (such as a nail or screw) driven into the batter board or foundation form board to indicate a desired location. 
     In one embodiment, the system may incorporate a live graphic user interface (GUI), e.g. 
     as part of the control unit  210 . The live GUI allows for real-time adjustments and updating of the location of the building on the building pad in the field.  FIG.  17    shows a display  1700  of the GUI, The display shows an outline of a plot of land  1710  featuring contour lines  1712  and the original or planned location of a building  1714 . The display allows the building to be selected and moved around to new locations  1720  positions on the plot display  1710 . For example, the building may be rotated slightly or shifted to take better advantage of the available view scape. The GUI may display renderings of the available view from the doors/windows of the building, based on the location/angle of the building design correlated with sensor input. When the building location is locked in on the GUI, any adjustments to the building location/orientation may then inform the building orientation and corner locations through the laser pointer or augmented reality applications mentioned above. Updated plot plans can then be generated showing the new building location/orientation, based on the field data. 
       FIG.  18    shows how the system can be used to indicate locations of features not directly adjacent to foundation form boards.  FIG.  18    shows a building layout  1800  featuring building extension batter boards  1810 , foundation form board string lines  1812  and foundation form boards  1814  that indicate the edges of a building foundation. However, there may be additional features that are required on the site prior to the concrete pour such as a waste pipe or other conduits. To mark such features, the digital layout software may calculate locations on the form boards and/or batter boards for anchoring string lines. The locations are calculated such that string lines running between these marked points intersect at the desired location of the feature.  FIG.  18    shows four string anchor locations  1820  marked on the form boards  1814 . The anchor locations  1820  may be marked on the form boards  1814  at the building site by placing the marking actuator described previously onto the form boards  1824 . The position of the actuator can then be controlled so indicate the required position of the string anchor location  1820 . String lines  1824  may then be run between the anchor locations  1820 . The point  1826  at which the strings  1824  intersect thereby marks the location of the feature. 
     Many modifications and other implementations of the disclosure set forth herein will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific implementations disclosed, and that modifications and other implementations are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example implementations in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative implementations without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.