Filter Ground Points

[Pointdump]

Filtering ground points has been the dream of great ReCap users ever since Civil 3D yanked point file functionality.

I had high hopes when I saw the new Automatic Ground Classification. Is it possible to filter ground points only? I've tried with classified and unclassified point clouds, but it does not filter any points no matter what I do.
Dave

[ramesh_sridharan]

@Pointdump, do you see the UI popup and processing progress bar? Does filter fail right after initiation? Can you please provide us little more information to identify the issue? Please feel free to DM me if you want a secure location to share data for testing. Thanks,

[Pointdump]

Hi Ramesh,
Thank you for responding.
I've tried this with both classified and unclassified point clouds. When I import the point cloud into Civil 3D, it's showing 984219 points. Here's some screen shots and a point cloud attached.
WGS 84 / UTM zone 11N + NAVD88 height
EPSG:32611
WGS 84 / UTM zone 11N

histogram of classification of points:
539381 unclassified (1)
92426 ground (2)
193 noise (7)
352264 Reserved for ASPRS Definition (19)

Dave

[Pointdump]

Ramesh,
Attached is ARRA-VA_11County_2010_000539.laz, which I lifted off The National Map:
NAD_1983_HARN_StatePlane_Virginia_South_FIPS_4502_Feet (EPSG:2925 US Survey Feet)
histogram of classification of points:
     5173619 unclassified (1)
     1658106 ground (2)
     2395 noise (7)
After I delete the unclassified (1) and noise (7) points, I still have all 6.83M Points. I'd really like to know if I'm missing a key step, or maybe I lack some key understanding. Please test this and let me know if you are able to filter ground (2) points.
Thank you,
Dave

[ramesh_sridharan · Accepted solution]

deleted points based on Classification is not readable by C3D by just saving. If you export to new RCP/RCS, then you will see only the undeleted points. 

[Pointdump]

Ramesh,
"Deleted points based on Classification is not readable by C3D by just saving. If you export to new RCP/RCS, then you will see only the undeleted points."
I did save as RCP/Support Folder. That does not honor the deleted non-ground points. How can I filter ground points to use in Civil 3D?
Dave

[ramesh_sridharan]

Can you try exporting? FYI We are working on supporting save/save-as in near future. 

[Pointdump]

"...exporting?"
What is the difference between exporting and saving? How do I export?
Dave

[Pointdump · Accepted solution]

Ramesh,
OK, kludgy and counter-intuitive, but this seems to work. There's a distinction between Saving and Exporting:
Step 1. In ReCap, delete all classifications except Ground(2).
Step 2. Hit the "Automatic Ground Classification" Button. Save Project >> Optimum.
Step 3. Don't save, instead use Export as RCP.
Step 4. Import the new RCP cloud.
Step 5. Create Surface from Point Cloud.
Step 6. Check Surface Properties. Should be just ground points (2) now.
I ended up with 1,586,361 ground points, which means ReCap decided that 71,745 ground points from the point cloud were not truly ground points.
Dave

[ramesh_sridharan]

Yes, the distinction is that saving technically does not delete the points but juts flags them as delete so that user have option on undoing later while export exports only undelete points. Here is the blog post for this workflow.