Selecting Points in a pointcloud with SelFence

This video shows my “Surface from pointcloud methodology” that I am trying to improve.

I am now trying extracting sections through a pointcloud using _CurveThroughPt + Selfence
It works pretty well, but I would like to be able to reduce the thickness (width) of the fence to select a thinner slice of points in the pointcloud.
At the moment I can only fudge this by zooming into the Fence curve when I execute the command.

Hi Mike - have you tried PointCloudSection? you get to set a distance from the section plane in that command.


Hi Pascal, the section tool only creates straight lines, I would like to be able to extract curved sections if possible.

Hi Mike - try this: draw the curve, and use SelBrush > Curve at a very small brush radius - 3 px is the minimum I think.


Hi Pascal,
I just did a quick test.
I tried your method, draw the curve, and use SelBrush > Curve at a very small brush radius - 3 px.
I get a better result when I zoom in to select the curve.
So 3PX is relative to the viewport zoom. Is there any way to set an absolute selection width (in MM )

Sorry, I am asking a lot :slight_smile:
What about a visual representation of 3px width on a Curve ? similar to when I use Selbrush without selecting a Curve option ?

Hi Mike - here is a really quick and dirty point selection tool - it finds points within a distance of a surface - if you extrude your curve through the points, this should find them if I did it right… we can make it fancier, for now just see if it does anything good with just points - we can make it work on point clouds - it defaults to model tolerance as the distance. (1.8 KB)

@Mike_A - updated to work on point clouds - it extracts a copy of the nearby points.

To use the Python script use RunPythonScript, or a macro:

_-RunPythonScript "Full path to py file inside double-quotes"


The script runs, asks me to select a surface, but doesn’t seem to select any points near the extrusion

Hi Mike- are the points still in a cloud? it will not work yet with a proper point cloud, just point objects.
Hold on, I’ll fix it for PCs.


You are right :), I just exploded the pointcloud (using Pointcloud command), it now works.

Standard Point Set Deviation still works on my unexploded pointcloud.

I will use your method, it works pretty well.
Thanks Again !

By the way Pascal, this script is perfect for checking 3D model “Clash Detection” against a pointcloud !
You could add it to the tools.

Hi Mike - updated with a little friendlier UI, above.


Hi Pascal,
This is why I am looking for good pointcloud tools in Rhino :slight_smile:

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