Point Cloud Display

[Jason__M]

Using Civil 3d 2012, I have a drawing with four seperate point clouds (each less than 44 million points).  I noticed that one of the point clouds seemed decimated and was not displaying all of the points.  I opened a new drawing and attached only this one point cloud and all of the points were being displayed.  In the original drawing with all 4 point clouds, I turned the layers of the other three point clouds off, trimmed the visible area of this fourth point cloud down considerably and regenerated the drawing.  Still not all of the points are displayed.  The point density is set to 100.  Is there another setting I'm missing?  Would this issue be caused by having four point clouds loaded - would I have this issue with one point cloud that was 176 million points?  I did not inspect the other point clouds to see if the issue was effected each of them equally.

[steves4]

I believe that even with the point cloud density set all the way to 100, the maximum number of cloud points you can view is 750,000.  If you limit your view to an area with less than that many points, you will be able to see all of the points in that particular area.

[tom]

Steve,

Thanks for the reply.  I was thinking it was more - I must have been thinking of the newer releases. 

Using Kubit to slice the cloud, I am still seeing the issue even when I am only viewing a very thin slice of the data (3" x 20'x50')  I'm wouldn't imagine there are more than 750,000 points in that slice. 

[scottydiaz123]

Hi All,

AutoCAD 2011-2012: You are limited to viewing 1.5 million points per point of view when your POINTCLOUDDENSITY is set to 100. This is a limitation of the AutoCAD graphics engine and a bit of a cap set by Autodesk to keep you from crashing. If you have a cloud of 150 million points, you are only seeing 1.5 million at a time. Even zooming in on the cloud, the engine is not capable of choosing the best 1.5 points for viewing. A billion points and it looks like a snow storm in CAD. These were the early days for point cloud handling natively in AutoCAD. Even with the clouds turned off or clipped, AutoCAD still detects the overall points of all point clouds in the drawing.The only way to make it look better is to reduce the number of points and work in smaller sections. 

AutoCAD 2013: By default you can view 1.5 million points with the POINTCLOUDENSITY set to 100. Same as 2011-2012. Witht he 2013 release, AutoCAD introduced the POINTCLOUDPOINTMAX command. This allowed users to increase the number of points from 1.5 million to as high as 10 million points. Be careful, the higher the setting, the slower your AutoCAD. Again, try to find a balance between number of points in AutoCAD and your machine's performance. Working in sections is helpful.

AutoCAD 2014: Same default of 1.5 million and optional POINTCLOUDPOINTMAX. The difference now is that users can choose to turn "Auto update" on or off. Notice in previous CAD versions, as you orbit or zoom, the cloud decimates, then regenerates when you stop. This is auto updating the point cloud dispaly based on your point of view. The software has to decide what are the best points to show from this view. You can turn off Auto Update. When doing so, you will notice more fluid motion and no decimation. Now try zooming; the cloud looks terrible until you REGEN. Now zoom out, the cloud seems clipped. Just type REGEN again. This is what happens when Auto update is turned off. One advantage is that you can turn your POINTCLOUDPOINTMAX much higher without slowing you down.

AutoCAD 2015: Well, you'll just have to wait and see, won't you? 😉 But i will lay my bet on significant improvement.

Summary: The AutoCAD graphics engine can't handle the new point cloud engine as it should. As a result, there are limits in place to keep things from collapsing. This video will explain/teach in more detail. You may also consider using Autodesk Recap (free version) for maanging your data sets into smaller portions for your AutoCAD sessions. The video reviews this as well. http://www.youtube.com/watch?v=fZFw4PW6N9A&feature=c4-overview-vl&list=PLibTjLVINSwOZ8EgqdGzv7tACgfE.... Let me know if you need more hints/workarounds.

Hope this helps,

Scott, kubit USA