Does rhino have some command to find a three-dimensional graphic's local concave point and convex point

Or how can i find a three-dimensional graphic’s local concave point and convex point.

Hello- see if this old Rhino Script helps - drag and drop the rvb file onto Rhino to add these aliases:

HighLowPt - not sure how useful that one is but the others should work OK if you click reasonably close to the actual high point.

I can see how these can benefit from some tweaking… I’ll see if I can do that.

Looks like it does not accept meshes but I can add that.

HighPt.rvb (2.8 KB)
Updated to accept meshes.


why are they unknown commands in rhino6?
how to use a file with .rvb?

Hi - these commands are not built-in into Rhino, they are provided by the script that Pascal wrote.
Notice his instructions on how to get these to work:

i have run the commands on some simple surfaces. but when i run on a complex surface,it made rhino in unresponsive state.

Hello - please post or send me an example, and I’ll see if I can figure out what is wrong.
@1351648725 - hello - I have your file - as I mentioned when I posted it, the script does not currently accept meshes as input. I may be able to fixthat but currently it does not.


Dear 1351648725
for nurbs-Surfaces:
did you check _draftAnglePoint ?
set the Angle to 90 degree and the vector to the desired word coordinates.

_draftAngleAnalysis will give you an first estimate, where to search

you can also use Boundingbox and some of the _intersect _Meshintersect …

hope that helps, best, Tom

Yeah - that is a good idea - it did not exist when I made this, (I use a ping-pong of closest points) but I like it!

@1351648725 I’ve updated my boring old version to accept meshes. I’ll replace the file above. Also, it is world based, so you’ll need to rotate your object 90 degrees so that the hills and valleys are in World Z.


your script can get the concave point and convex point of the whole surface.but i need the local concave point and convex point in some hills or valleys, do you know how to separate the hills from the surface, then i can get local concave point and convex point by your script.