Refining the ground features

[Nara]

Hello,

I was directed to trying this excellent software when I asked questions in the AutoDesk Recap and Map 3D forums. I am extremely new to point cloud data.

Traditionally, the company I work for measures buildings and although a laser scanner is used, we draw plans and elevations in 2D. Recently we were asked to provide information for the properties surrounding 2 buildings. One of which is practically flat, the other has a 10’ climb from front to back. That second one is what I'm showing here.

Wire Frame.PNG (422.34 KiB) Viewed 2621 times

After trimming the roof and other noise away, I ran the CSF a few times with differing parameters. For this particular run, I used “Relief, Slope Processing, 0.1 CF and 0.05 Threshold.

Ground Points and Mesh.PNG (708.39 KiB) Viewed 2621 times

Circled in blue are remnants of patio furniture. I still don’t like the spikes left from vegetation, but the furniture for certain should be removed.

Wire Frame.PNG (422.34 KiB) Viewed 2621 times

In ReCAP, I would “limit the box” from multiple x and y widths in order to cut out these features when looking side on but still keep the background as it’s effectively frozen out of view. I thought I could do similarly with the cross section knobs, but had no luck. Is it possible? If so, how?

Thanks!

[daniel]

With the Cross section tool, you have to 'extract' the slice (= create a new entity). This will duplicate the data, so that's safe. And then you can run the process on this excerpt. But that has to be done explicitly each time. Then remove the subset cloud if you don't use it anymore.

(also, unrelated, if you are using CSF, make sure to use the latest 2.13 version as the algorithm has been improved).

[daniel]

I'm a bit puzzled by the fact that you seem to work with a (Delaunay?) mesh instead of the point cloud... Is there any reason for that?

[Nara]

Hi Daniel,
Thank you for your reply. Yes, it is version 2.13.1 (Kharkiv- March 20 2024) [64-bit] that I downloaded and am trying to use.
Hmm, that is more cumbersome than I'd hoped and I'll have to learn how to patch all the segments back together.
I don't know the reasoning. The client was sent the e57 and replied with a folder of examples of how they'd prefer the data see attached images. I've been tasked with trying to present is similarly.

[daniel]

Ah ok. It looks a lot like the 'countour plot' option of the Rasterize tool.

So I would try to remove the non-ground points (with CSF, scissors, etc.) directly from the raw cloud. And then use the 'Rasterize' tool.

[Nara]

Thank you, Daniel,
I am now looking at Youtube tutorials for using Rasterize.