Can't get Collision to work on custom part

[BlackFang]

I can get my part in the game, but I can't seem to get collision to work. Is there anything obviously wrong that can be seen in this picture?

[lo-fi]

What's happening exactly? You've got convex selected, and the layer is set to default which is all correct for that kind of part. Doesn't look like you've gone over the 255 tri limit for mesh colliders, but try making a simpler object (less side, maybe 10 or 12) for the collider, or ditch the mesh and create an empty GO to apply a capsule collider to to see if that helps.

[BlackFang]

I don't know why, but I erased the Unity project and started another blank one. I did everything the same and now it works.

[lo-fi]

Put it down to 'one of those things'. Glad you got it fixed Do look into making a simpler collider, though. They're a more resource hungry with higher tri-count, so the less you can get away with the better.

[NecroBones]

I don't know why, but I erased the Unity project and started another blank one. I did everything the same and now it works.

Wow, strange. I've had something like that happen before, but with something else entirely (not a collision mesh, but I can't remember the details now). I suspect it's possible to have some corrupted settings somewhere, in something that Unity hides from view.

Do look into making a simpler collider, though. They're a more resource hungry with higher tri-count, so the less you can get away with the better.

Agreed on this. The "normal" way for Squad-made fuel tanks, is to have 24 sides for the model, with vertices aligned to the cardinal axes, with a collision mesh that is 12-sided, with the sides (instead of the vertices) aligned to the cardinal directions. You don't have to adhere to this, of course, but doing it this way pretty much ensures that things work the way you expect in the VAB/SPH.

The CPU usage for physics goes up with each additional polygon in the collision meshes.