Hey there,

I tried to import a simple obj file into Houdini and use it as an collision object to experiment with particles. However, some polys of the mesh aren't being recognized which leads to strange and undesired behaviour in the simulation.

Could someone explain me how to fix this? Thank you! )

Maybe the normals on your OBJ are reversed?

Or if that doesn't work, look at the static object in DOPs, and go to Collisions > RBD Solver > Volumes, and turn on ‘Collision Guide’, to see what it looks like. You might need more resolution?

And if you can post a hip file, generally that helps get questions answered more quickly!

Hey goldleaf. Oh yes, the collision guide showed me that the walls were all flattened out.

That helped to solve the problem, thank you very much! I should have added the scene, unfortunately I didn't think about that. I can see now that this was quite vague. Thanks again!