Abstract:
A method and system of rendering buildings in three-dimensional space first renders a respective floor, then adds objects and finally walls to bound each of the floors. The result, a three-dimensional rendering of a building, has translucent walls and illustrates the position of objects within the building in addition to presenting the overall shape of the building. The building can be rotated or enlarged to clarify the position of the various objects in space.

Description:
FIELD 
   The invention pertains to the creation and presentation of three-dimensional images on two-dimensional graphical displays. More particularly, the invention pertains to systems and methods for generating three-dimensional renderings of building spaces and presenting same on two-dimensional graphical display devices. 
   BACKGROUND 
   Known software and hardware is available for rendering various types of three-dimensional images including building spaces. Known methods and systems at times do not clearly or accurately depict the location of objects in a rendered image of a building. Further, at times the positional relationships of objects to one another, when the objects are located on multiple floors, are not always clearly depicted. 
   Known systems include the use of graphics hardware to attempt to generate accurate three-dimensional images. Other known methods seek to improve accuracy by rendering the back walls first. The objects in the floors are then drawn. Finally, the front walls are rendered. Such processes can suffer from performance penalties other drawbacks. 
   Known systems and methods often do not accurately render transparency and depth simultaneously in a three-dimensional structure unless the polygons used to create the images are rendered from back to front. However, in such processes, sorting of polygons can be either inefficient or unfeasible due to time and depth processing requirements. Thus, errors can arise from currently used techniques for transparency which ignore depth or techniques for testing depth which ignore transparency. 
   There continues to be an ongoing need for systems and methods for rendering multi-dimensional building spaces accurately. Preferably it will be possible to accurately locate objects on the respective floor or floors as well as accurately render transparency and depth simultaneously without having to sort polygons. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is block diagram of a system in accordance with the invention; 
       FIG. 2  is a flow diagram of a method in accordance with the invention; 
       FIG. 3  is an image of one step in the method of  FIG. 2 ; 
       FIG. 4  illustrates another step of the method of  FIG. 2 ; 
       FIG. 5  illustrates a third step of the method of  FIG. 2 ; 
       FIGS. 6A ,  6 B illustrate various views of a rendering of a building as in  FIG. 1 ; and 
       FIG. 7A ,  7 B,  7 C taken together illustrate developing emergency indicating trends incorporated in the rendering of a building of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   While embodiments of this invention can take many different forms, specific embodiments thereof are shown in the drawings and will be described herein in detail with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention, as well as the best mode of practicing same, and is not intended to limit the invention to the specific embodiment illustrated. 
   Systems and methods which embody the present invention provide renderings of three-dimensional, multiple story buildings using a translucent representation of the building. The location of objects within or on various floors, can be depicted. Such objects include interior walls, smoke detectors, evacuation stairs, elevators, hazardous materials, and doors without limitation. 
   Further in accordance with the invention, the building representations can be rendered in a translucent light grey color. The preferred color prevents the rendered wall from discoloring or occluding icons which are used to represent objects throughout the building. Preferably the floors will be rendered darker than the walls. This has the particular advantage that the darker floors visually anchor the objects to a particular floor and space such that they do not appear to “float”. 
   In one aspect, control software can rotate the representation of the building or object about a vertical axis. Continuously changing the visual parallax can further convey the positions of objects in space along with depth and distance relationships. 
   In another aspect of the invention, floors of a building are rendered from bottom to top. Preferably each floor is rendered first without any need for depth testing. Objects can then be positioned on the floor with depth testing. Finally, the walls can be generated without depth testing. 
   Where wall transparency is relatively faint, any inaccuracies due to displaying walls behind an object for the same floor on which the objects reside may contribute color to the object. However, such inaccuracies are substantially undetectable where the wall transparency is faint. 
   In a further aspect of the invention, the state of various objects within the building, such as ambient condition detectors, can be presented in substantially real-time for use in establishing fire location, direction and extent in the rendered structure all without limitation. The location of first responders on various floors can also be displayed substantially in real-time. 
   By means of a graphical interface a user can start or stop rotation of the building being presented, or zoom in and out along a line from a fixed viewpoint to better understand the relationships between the various objects and floors of the building. 
   In yet another aspect of the invention, a multi-story building can be rendered, for example in a fire situation display, for use by first responders to assess the location and extent of a fire condition. Such a display can also be used to locate what might be multi-story paths to the fire for purposes of suppressing same as well as paths to individuals located throughout the building for purposes of assisting them to safely leave the premises. 
     FIG. 1  illustrates a system  10  which might be distributed throughout a plurality of floors of a building B 1  for purposes of monitoring various conditions throughout the building. Representative conditions could include fire, smoke, gas, operation of a HVAC systems, illumination systems, and/or security systems all without limitation. 
   System  10  could incorporate a plurality of ambient condition detectors scattered throughout the building indicated generally at  14  for purposes of monitoring various conditions throughout the building of B 1 . Signals that pertain to outputs from detectors  14  could be coupled to a fire situation control and display unit  18 . The unit  18  could be in wired or wireless communication with various of the detectors  14  scattered throughout the building B 1 . 
   Information pertaining to conditions within the building B 1  could be presented one or more local visual displays. Such displays could provide information pertaining to the state of one or more of the members  14   i  of the plurality  14  of ambient condition detectors. 
   Unit  18  can be implemented with control circuits  20   a  which could include one or more programmable processors. It will be understood that the processors need not all be located physically near one another. They could communicate via one or more networks. 
   Unit  18  can also include control software  20   b  executable by one or more of the processors of control circuits  20   a . The software  20   b  implements communications with the plurality of ambient condition detectors  14 , as well as other displaced devices via a wired and/or wireless medium indicated generally at  20   c - 1 . Communications can be provided to other sites via a wired or wireless medium  20   c - 2 . 
   The unit  18  can also include software  20   d , discussed in more detail subsequently, for presenting one or more renderings of the building B 1 . The renderings can be presented locally on a two-dimensional visual display unit  20   e  which can be viewed by first responders in the vicinity for purposes of understanding the layout of the building B 1 , including location of stairways and elevators in the building, location and arrangement of the members of the plurality of detectors  14 . Those detectors which are emitting indications of an alarm condition can be highlighted. 
   Unit  18  can also include one or more databases such as database D 1  which can include static information concerning building B 1  and/or a pre-created multi-story rendering of the floors of the building B 1  in accordance with the present invention and methodology as described subsequently. 
   Database D 2  can incorporate real time dynamic information relative to conditions within the building B 1 . Such information can include identification of those detectors of the plurality  14  which may be indicating an alarm condition as well as time of entering that state, fire fighter location and related information as would be understood by those of skill in the art. 
   It will be understood that the system  10  is exemplary only and is not a limitation of the present invention. Further, the type and nature of the detectors in plurality  14  include without limitation those types of ambient condition detectors as would be understood by those of skill in the art to be of interest in monitoring building conditions or the like. For example, the members of the plurality  14  could be security related detectors which include motion sensors, position sensors and the like for purposes of securing the building B 1 . In such embodiments, the software  20   d  could in turn display activated security related alarms indicating paths of movement of one or more individuals in the building. Thus such information could also be combined with information from other members of the plurality  14  including fire detectors of all types, gas detectors and the like all without limitation. 
     FIG. 2  illustrates a process  100  for rendering the building B 1  as a substantially transparent image which could be presented on the display  20   e  for use by first responders in the event of an emergency. The process  100  can be implemented off-line for purposes of creating renderings of the various floors of the building B 1  and then stored in a local database such as a database D 1  for subsequent presentation on the display  20   e  as needed. Alternately, the software  20   d  can carry out the rendering process based on static building information stored in the database D 1 . It will be understood that no limitation is intended and relative to when and where the rendering of the building B 1  is created. 
   The rendering of the building B 1 , in accordance with the process  100  takes place one floor at a time starting at the first floor of a multi-floor building. A floor number, n is set to “one” step  102 . 
   In a second step  104 , the floor is rendered. For example, see rendering  50  in  FIG. 3  for a floor  50 - 1  presented on a representative screen  52  of a unit such as unit  20   e . As illustrated in  FIG. 2 , static building information to render the current floor, as in step  104 , is provided from the pre-stored database D 1  which includes the static information necessary to specify the building B 1 . 
   In a step  106  static objects from database D 1  can be rendered relative to the current floor  50 - 1  as illustrated in  FIG. 4 . Objects can include those structures of static or substantially permanent nature on a given floor such as stairs or elevators  50 - 2  as well as ambient condition detectors, alarm indicators such as sounders, voice output devices, strobes and the like all without limitation  50 - 3 . 
   It will be understood that in the step  106  static location information can be obtained and utilized from database D 1 . Where the rendering is to include real-time condition or status information, the database D 2  can be accessed for information pertaining to activated alarms, activated output devices, first responder locations (based on wireless communications) and the like all without limitation. Such information can be provided on a real-time or substantially real-time basis of if desired while the rendering is being created and subsequently at the display  20   e  or at any desired displaced location. 
   In a step  108  a determination is made as to whether all floors have been rendered in which case the image of the building is complete. In such event the image is available for rotation or analysis by first responders or other involved parties. 
   In the event that the rendering is not complete, the walls for the current floor are rendered, step  110 , best seen in  FIG. 5 , wall  50 - 4 . The walls can be rendered in any order. Subsequently the floor number is incremented, step  112  and the process is repeated until the roof is encountered, step  108 . 
     FIG. 6A  illustrates an exemplary completed rendering  54  on a display such as the local display  20   e  or a displaced display. As illustrated in  FIG. 6A , each of the floors, such as floor Fi is first rendered then object representations such as elevators; stairs or the like Oi, objects such as ambient condition detectors, or output devices, Di as well as sources of a type worn by first responders and the like all without limitation are located and displayed on the respective floor. The floor Fi is then bounded by the respective walls Wi which are rendered subsequent to the floor Fi and the related objects Di, Oi. 
     FIG. 6B  illustrates rendering B 1 -R, the same building rendering as in  FIG. 6A  from a different view and with a different degree of magnification. Those of skill will understand that the software  20   d  can rotate the respective rendering as well as magnify some or all of it for purposes of examination. 
   It will be understood that the displays of  FIGS. 6A and 6B  can be particularly useful and are beneficial to viewers since the respective building renderings are presented as if building B 1  was constructed of a translucent material, such as a gray tinted plastic. The configuration of the rendering of B 1 -R which involves a three-dimensional perspective rendering of the building B 1  with translucent walls makes it possible to convey the position of objects within the building in addition to the shape of the building. Further, the ability to rotate the rendering B 1 -R via software  20   d  along with associated objects, can clarify the positions of the objects relative to the various floors. Ongoing trends in the building can be displayed in proper spatial relationship to floors or objects. 
   It is a further advantage of the renderings of the method  100 , as illustrated in  FIG. 6B , that the respective building can be rendered in a translucent light gray color. This avoids problems with the walls discoloring or occluding representations of objects in the building. Further, the floors can be rendered darker than the walls. This has the advantage that the darker tint to the walls visually anchors the objects to a particular floor in vertical space as opposed to presenting a “floating” image. 
   Rendering errors are reduced in accordance with the method  100 . Minimal inaccuracies might occur where a wall is located behind an object on the same floor. In this case, the object will tend to contribute its color to the object. This effect can be minimized with the use of faint wall images. 
     FIGS. 7A ,  7 B and  7 C taken together illustrate the presentation of developing trends, in real-time or substantially real-time based on a combination of static building information, database D 1 , as well as feedback from members of the plurality  14  as to detectors indicating an alarm condition. As illustrated in  FIG. 7A , detectors Di, Di- 1  are exhibiting an alarm condition and would be presented on the display  20   e  in an active or alarm state. 
   In  FIG. 7B  displayed subsequently in time, the same detectors continue to be in an alarm state and detectors Di- 2  and Di- 3  have now started exhibiting an alarm state. Finally, in  FIG. 7C  additional detectors Di- 4 , Di- 5  and Di- 6  are exhibiting an alarm state and indicating a definite direction and trend as to the developing emergency condition. It will be understood, as discussed above, that the software  20   d  can then be used to rotate the rendering B 1 -R to provide a clearer understanding of the relationship between the active detectors and other objects on floor Fi. 
   From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.