Point Cloud Density

[Anonymous]

Now that Revit 2012 can import point clouds we are keen to make use point clouds for existing buildings.

But a surveyor has asked what density we would like the scan to be.

Depending on the equipment used, densities up to 0.25mm seem possible. But surely this would create more points than are useful, and a HUGE file.

Accuracy seems to be around +/-5mm, so why would you require a higher density than that? But maybe a lower density is sufficent. 10mm?

Does anyone have any experience in using point clouds, and in particular what a suitable density might be.

[alan.quinn]

I would get whatever you can handle size wise. You can always make it smaller after the fact.

Hope this helps and thank you,  

[Anonymous · Accepted solution]

I asked a Surveyor.

They said a high density survey can have its density reduced with software quite easily.

But as we don't have the software we would have to tell them what density we wanted.

They suggested between 10-20mm  (3/8"-3/4") point to point as a reasonable density.

[alan.quinn · Accepted solution]

I asked around and here’s what I found out. Revit will show the point cloud information it can, it chooses the points to display and may not display all points in the cloud at the same time. So it sounds like whatever you get will work.

Thank you,

[nmoore]

This tool is not ready for release.  Portions of the data disappear as you zoom in to try to work with them.  The a so low density by the time Revit has indexed them they are of little value.  We will need to have options for the indexing to allow higher densities at the users descretion.  For now I would recommend about the cloud density you called out for buildings.  We have done several buildings and hundreds of pieces of equipment for food plants in revit before this tool.  We use a much tighter spacing for the equipment.  You really need to have them scan to density of what you need, segement the data in their tool into sections, use a larger low res cloud for alignment export to dwg and import into revit to preserve any kind of realistic density.  This will be a great tool if Autodesk works the bugs out, but right now its still not there.

Thats my two cents after a few hundred hours 'in the cloud'  🙂