Collisin Models

[Ishtvan]

This is what Brian said about collision models:

 

You also don't need a seperate .cm file for models because you can put

the collision geometry directly in the model file (just use a surface

with the common/clip texture).  Note, however, this doesn't work for

characters.  They use a bounding box when they are alive and an AF when

they are dead.  The AF collision geometry is set up with the AF Editor

(editAFs).

 

So... I'm still not sure what that means. I guess we don't have to worry about collision models for characters until they die. That still doesn't help my code any tho.. I emailed him some follow-up questions.

[Domarius]

I've read a bit about this, and this is how I understand it;

 

For models that aren't characters (animated), the actual mesh can be used as the colision model, for physics purposes. So those crates with the beveled corners really do have beveled corners as far as the physics is concerned (rather than just being a perfect box).

But if you had a fairly complex mesh (maybe a severed hand), you'd really want to make a CM for that to avoid wasting physics processing on useless amounts of detail.

 

For characters, since the polygons are moving around all the time because of animation, this would be insane to test physics against.

So for them, unless you specify a CM, it just resorts to bounding box collisions.

Then when they die they become a ragdoll (Articulated Figure type thing).

 

So you need CMs for characters if you want to be able to shoot between their legs and miss, but shoot an individual leg and hit. I'm sure there's info on Doom 3 world about how to create CMs.

[Ishtvan]

I can shoot between the legs of our haunt model and miss, even tho we didn't do anything special to get the CM for him...

 

[edit: I THINK, I could be wrong, have to test this]

Edited April 6, 2005 by Ishtvan

[Domarius]

Well before I read your post from Brian there, I was under the impression that it gets the CM from teh Mesh even if it IS an animated character. (Which of course is the bad option)

[BlackThief]

well that's kinda strange. when I set-up the barrel I get an error in the console, that it's not possible to use the mesh of it because it has too many vertics....hell it's a barrel - there aren't a lot vertics on a barrel, so it seems that the collision models have to be very simple

[Domarius]

Well, it makes sense I guess. It's gotta calculate physics on that shape, so... I guess I read an over-simplification.