Need help with setting up a simple collider for a model I made in Unity

I just started using unity, and I'm trying to add a collider to a object resembling a conference table.


However, when I add it, the "hit box" goes straight from the top of the table down to the base without accounting for the area between the surface of the table and the supporting block under it. This is hard to explain but here is a picture of the hit box:


As you can see, when the table falls directly above the cube, it falsely triggers a collision.

I would like to know how I can fix this. Any help will be appreciated.

 

For a shape like this, just remove the MeshCollider, and instead add two BoxColliders, one for the top and one for the bottom. (You could also uncheck "Convex" on the MeshCollider, but mesh colliders have various limitations and annoyances, so box colliders are always better when you can use them.)

Now it's my turn to ask a question: how exactly did you make this model in Unity? I didn't think it had any mesh-creation tools built in.

 

To answer your question, I created the model within Blender. I'm not really sure what Convex exactly does, but when it's unchecked, the model falls right through the surface. Furthermore, the surface was also made in Blender, it uses a box collider, if that is of any use.

Another more complicated example would be this:

When I turn off Convex, it falls through the ground

 

OK, that makes sense. I thought your first post said you made this model in Unity, which surprised me.

Yeah, non-convex mesh colliders are mostly useless. Stick to boxes, spheres, and capsules when you can. A convex mesh is second best. (Google the term if you really want to understand what it means.)

 

Thank you for the advice, do you have any recommendations for more complex models like office desk shown above, for which I can't solely use basic shapes like boxes and circles?

 

Actually, you probably can. Keep in mind that it doesn't have to be perfect. Game development is all about finding the good enough and pulling whatever tricks you can to increase performance. So, you don't try to capture every nook and cranny; you don't worry about the undersides of things that you never expect to matter; etc.

 

Okay, thank you for the help!