C3D - POINT CLOUD

[cturlington]

Hello,

I am working with Civil 3D 2017.

I received a file with a point cloud in it.  The engineer is asking me to filter the points so can use just the ground points for a surface.  There does not appear to be away to work with this point cloud in Civil 3D.  Is my observation correct or can I filter the points somehow?  I would try ReCap but I do not have the *.rcp file extension...

[tcorey · Accepted solution]

If the point cloud is "classified", meaning the points have attributes that say whether they are ground, vegetation, building, etc., then you can use that to filter the point cloud.

If the point cloud is unclassified, well, like anyone who gets into this field, you've discovered the need for what would be the holy grail of point cloud processing, particularly for those who use drones and photos, not lidar.

For lidar scans, whether by drone or terrestrial scanner, there are some options. LAS Tools has a utility that finds the bottom points and returns a set of ground points. There is a plugin for Cloud Compare, called CSF Plugin - stands for Cloth Simulation Filtering - that uses algorithms that turn the cloud upside down and then drape a virtual cloth over it to find the ground. 

[dgorsman]

What format do you have?  One of the reasons for the ReCap program is it can read a wide variety of formats, including both neutral ASCII and proprietary vendor.

[cturlington]

dgorsman,

The point cloud was handed to me inside a dwg file.  All I know about the format is I do not have the *.rcp format for ReCap.

[Pointdump]

Chuck,

In Prospector do you have a Point Cloud? Have you tried changing the Point Cloud Style to "LiDAR Point Classification"?

 

Dave

[cturlington]

Dave,

Yes, I have a point cloud in prospector.  I did try your suggestion on the point cloud style adjustments to see if I could isolate the ground points.  However, I was not getting any useful performance unless I used True Color, but otherwise I keep getting a single continuous color.  Wish I could just remove some of the points.  But I can add to surface and delete tinn points, but is very time consuming.