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Point Clouds in Revit

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    Point Clouds in Revit

    Curious.... How are people using point clouds in Revit? It seems (from reading since I don't have any of my own) all I can do with them is build geometry based on them saving me time of taking measurments I guess. Is there anything else I can do with them? Can they be edited in revit? for example moving pieces of equipment represented by point cloud. Can parts of them be deleted? Intrigued by the potential they present, but cautiously optimistic.

    Opinions may vary, but presently i still find it faster and more reliable to model off of drawings (if i have them), and then importing the point cloud as a check. Or, importing the point cloud, and modeling the normal way, using it as a . The tools for making geometry *right from* the PC are sluggish and slightly cumbersome to use, and the way they interpolate the points to build the model, im not satisfied that you get a higher level of accuracy.
    Aaron "selfish AND petulant" Maller |P A R A L L A X T E A M | Practice Technology Implementation
    @Web | @Twitter | @LinkedIn | @Email


      I concur with Aaron's comments. I find the use of existing documentation is a good place to start to develop a frame work for the point cloud to overlay. For example if the documentation shows the grid layout for the building is 10'-0" center to center and the point cloud shows that the columns are actually 10'-2" center to center in three bays and shift to 10'-6" for two others. You can start to document the variations between what you expected to find in the building and what you've got.

      Point cloud data can be a bit noisy. You can end up with shadow points, points that literally form shadows past edges where the scan couldn't see. When you overlay several scans that tell the whole story these shadows are less confusing but they are still there. I find that I need to go back and forth between Revit and point cloud software like Scene (FARO) or Cyclone (Leica) or Point Tools to check point coordinates to compare with the model as you go. Then it all comes down to what the model is intended to do, what the client (or you) really want to know/see/do with the model.

      You can't edit the point data in Revit. Revit also decimates the "cloud" to reduce the performance load on it. I've also read that Revit only displays a certain maximum number of points in a view at any one time, to manage performance, but it hasn't been so noticeable to me that I reacted to seeing less suddenly. I had 126 point cloud (.pcg)files referenced into a Revit project file recently and performance was really pretty good. It took awhile (minute or two sometimes) to open whole model views but once the view was open navigation was fine. I setup views and view templates to manage turning on and off blocks of scans at one time. I used this model as a frame of reference and linked it into the building model where I did the modeling work.

      The beauty of laser scanning is that you have a 3D picture of the building that you can view, manipulate (with other software), and revisit anytime you want. Imagine documenting an entire existing building with a tape measure and/or surveying equipment. Imagine it is in another city and you realize you didn't measure something. You took some pictures so you can see it but you can't really measure it (Autodesk's Photofly might have some interesting options). The equipment isn't inexpensive, hiring someone to do it for you isn't either but you end up with files that "remember" everything the laser "saw". The quality of the image you can view in software like those mentioned earlier (if you think Revit is expensive...) is pretty impressive, photo quality, even in color with some equipment. The quality isn't the same in Revit (not photo quality) though but as an overlay within the Revit model it's pretty good.
      Mr. Revit OpEd
      Last edited by Steve_Stafford; September 16, 2011, 07:30 AM.


        Photofly is actually what I was looking at for getting the point cloud data, We were looking at rearranging some equipment in our plant and I thought it might be something worth doing a little testing with photofly and point clouds, but was having a little trouble visualizing the steps I would have to take and whether it would be worth the time, trial & error. For now, 'cause you can't ever get something done fast enough, I just made box representations of of objects and modeled columns and walls. I have learned that there is a point cloud to 3D model tool for autocad that might make things easier as I could build a model of each piece of equipment in autocad and import into Revit for arranging and visualization. So I think my process would have been take 42 bazillion pictures of each piece of equipment, upload to photofly, export the point cloud data, import/translate clouds in AutoCAD with tool, load each dwg into a family and place into a project.


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