MeshinMesh

[Firlefanz]

Hello,

I need a function like MeshinMesh.

I want to know if two meshes collide. Perhaps first check the bounding boxes and the distance, and then checl the polygons or something.

I need it in 3D not 2D, I found a lot of stuff for 2D already.

Does anybody have already something like this? Or do I really have to use ODE or Newton, is this that complicated?

Thanks,
Firle

[Mirage]

Checking of two arbitrary meshes for collision is a quite complicated task. Even not any physics engine supports this. AFAIR Newton has polymesh colision support.

[Huehnerschaender]

... and I am sure you do NOT need this Eric

If you want to have it for the project I am thinking of then you definitely need a faster way to detect collisions. I guess games like Assassins Creed use this accurate collisions but a spaceshooter doesn't need it.

[chronozphere]

You could also simplify your geometry and make spheres and boxes out of it. Checking those is a lot easier and faster. Flattening your collision-meshes to 2d (if possible) might also work.

I think in most cases this will give you satisfactory results. What kind of meshes are you using? Does your collision-checking really need to be THAT accurate ? :?

OFFTOPIC: Yeeha: Word lord now!

[User137]

Testing sphere collision is faster than boxes (for the very first check). You don't need sqrt() call at all if you power 2 the radius too

After that the detailed collision which could be each triangle, model defined as a shape or numerous smaller shapes...

[lordzero]

maybe this can help...

is working 100% here...

http://www.lordzero.co.nr/tmp/AxisAl...udingBox3D.zip

[Firlefanz]

Hi @all

@lordzero,
how do you control the demo?
I am only moving the camera right now...

@all,
yes, this is for a spaceshooter, exactly.
I already have a collision check with sphere, but I find it not good enough.
I hoped to check the sphere first, and if that spheres collide do another check with the mesh or maybe the mesh simplified or something...

Thanks,
Firle

[lordzero]

@lordzero,
how do you control the demo?
I am only moving the camera right now...

numpad 4,8,6,2

[Huehnerschaender]

@lordzero:
Your demo does not work properly. When I move the right box so that it is behind the left box and then move "down", the box collides before it really hits the other box.


@Eric:
It is much faster if you attach a few invisible collision boxes to the models than testing Mesh2Mesh collision.

For example, if you have an airplane-like model you can easily use two boxes which are overlapping like a cross. This is much more accurate than a bounding box or sphere and is nearly as fast as bounding box-collisions. Think about it. You can "build" nearly every shape out of such simple constructs and use this for collisionchecks.

[Firlefanz]

Hmmm. I think this stuff with multiple collision boxes is the best idea until now.

Seems like I need some editor to load my model, then display and change and save 3 boxes or something, and in the engine when one box collides, I have a collision. Sounds good...and fast.

Just some additional new work with that editor then but that would be okay. Thanks for the clue Dirk.