I want to create simple collision response system (physical simulation is not required now). It is needed just that player can't go through walls.

I consider some variants: - Just create a set of primitive colliders (like AABB, OBB, Spheres) and check collisions in every frame (this approach is impemented now) - Create a BVH for the big level mesh and check collisions with small set of triangles. - Combine these two approaches and use BVH for determine which colliders I need to check.

But, probably, these variants are wrong. What algorithms and appoaches would you advice for this purpose?

  • \$\begingroup\$ What specifically is "wrong" about the approach you've described? It sounds like a rough outline of every physics engine I've seen. \$\endgroup\$
    – DMGregory
    Dec 7, 2018 at 12:03

1 Answer 1


In my experience, collisions that involve concave meshes sooner or later gets you in a mess.

If I were you, I would keep your current approach of tests that involve convex shapes: there is no ambiguity about inside/outside, and no nasty stuff like self intersecting meshes.

Just make it so that everything in your world has two representations: a visual model that can be as fancy, and as concave as you like.

The other representation for collisions, which is purely a collection of convex shapes, and only roughly follows the object's shape.

As an example: the visual model of an exquisite Edwardian table could be 4000 triangles. But it's physics shape is just 5 boxes.

The worst thing you could do is collide an arbitrary mesh against another arbitrary mesh. It's wasteful, and leads to horrible collision responses.

One more note: Convex dynamic objects against a static concave terrain mesh is often acceptable though. But if your terrain is a bunch of rooms that can adequately be described with boxes, I wouldn't even do that.


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