Select vertices based on proximity or bounding box

[sjrohitFAEQA]

Hi,

I have two geos which are intersecting with each other. I want to select the vertices of the first geo based on the position of second geo.  Or in other words, I want to select the points of first geo which are inside the second geo. Is there any way to do this?

thanks in advance!

[mcw0]

You can use position obviously.  And based on the shape of your objects, you can also use surface normals.  There is a thread in Bifrost where someone made a collision graph to push intersecting vertices out of another object.  So it's definitely possible.

[Kahylan]

Hi!

To find out if a vetex is inside another object, raycasting is probably the best way to go.

The principal is to use the position of the vertex and cast a vector into a random direction and check how many times the vector intersects with the other object. If the number is even or 0, the vertex is not in the object, if the number is odd, it is inside. Now if the geometry you are checking against has holes in it, using multiple rays and then using the result that most rays give you is recommended.

I'm currently not on my working machine. But I found a good github example that shows how raycasting can be done using the python API:

https://gist.github.com/SlyCodePanda/46a47e0193074154eadbabfa8500b2a7

I hope this helps!