I am working on a kit for procedural caves and I built a couple parts to test and realized my models don’t really lend themselves to having collision data. I want the kit to be versatile for first and third person so collision accuracy is semi important.
I was wondering how other people handle collision on kits like this. I’ve thought of a few solutions but wanted to see what others have done or maybe what others may recommend.

Kindest Regards,
Just add MeshCollider component on the same object where MeshFilter is located.
Mesh will be automatically inserted into MeshCollider component and it will work.
Make sure that checkbox “Convex” is disabled.
Also note that only “Convex” colliders will be able to collide with cave (it is the same principle as Unity Terrain)
Or you are asked about something different?
My concern is that doing that will cause physics issues since they are one sided. Low frame rates can cause issues with thin objects.
You can create special mesh for collider in the 3d editor where you created mesh of the cave.
Just add “Solidify” modifier (in Blender) or its analogue in others 3d editors, import this model into Unity and use this mesh instead of original one.
But first I would recommend to perform some tests with fast moving objects. Maybe it will work well, since terrain colliders always works well.