modeling How to select points or edges only inside and only outside of a circular ring plane

[Ikuya]

I have recently been doing some environment modeling in Houdini and often create ring-shaped planes, and I would like to know if there is a smart way to select and create groups of points for inside only or outside only. Currently I am using group bounding spheres, but ideally I would like to do it procedurally.

untitled.hip

 

[Ikuya]

In most actual cases, it is not a regular circle, but an ellipse, oval, etc. Any advice would be appreciated.

untitled2.hip

 

[Aizatulin]

You can group unshared edges and use lab edge group to poly. After this you can apply polypath and sort the prims by (measured) length.

untitled2_keep_inner.hipnc

[animatrix]

Ideally you should add this data to the points before you create the shape like this:

 

But if you can't do that, then here is one way where you can find the largest polygon by area, create a point group from that and then copy this point group back to the main branch:

[Ikuya]

I have tried the methods you have given me and all the examples have worked well for me. Thank you so much.

sample.hip