Is there any way to set collision hulls for individual objects? I have enemies of various sizes I want to use, but right now they all seem to use the same size collision hull, thus smaller enemies collide with the wall before the actually touch it, and bigger enemies overlap the wall quite a bit before they collide.

Check out these pages in the pdf manual (text copied from my pdf index):

hull ..... 79
hull_fatmax . 80
hull_fatmin . 80
hull_narrowmax 80
hull_narrowmin 80

Thanks for your reply. You must be using an old version of the manual; page 96 has the information about fat and narrow hull parameters.

At any rate, I'm quite familiar with that information. But that's also why I asked my question; the documentation seems to indicate that there can only be two hull sizes in a level, fat and narrow. Um, am I the only one who thinks that is a marvelously stupid limitation?

If noone can tell me how to set collision hulls for individual entities by the time I go home this evening, I'll be adding this to the wishlist forum.

The bad news: The hull doesn't rotate with your model. And I think one size fits all..
The good news: Conitec has indicated their future release of A6 will contain both a new physics engine, and a polygon based collision detection system.

Looks like they understand the problem, but the solution isn't going to be coming over the hill any time soon....

Assuming it'll work, I guess the feature Doug referred to will tide me over until A6.

you could always cheat. Just make an explosion 2x the size of the object, try to detract from the fact it hasnt hit. I suspect checking every poly in the game to see if its hit would take a lot of computing power anyway, even if it was implemented.

Or a shield that appears around objects as hit the collision routine detects two objects touching. then have it explode.

Here is what I am doing for my collision detection between entities and map objects (since I don't like the way hulls work for the same reason - they too often pass halfway through walls etc).

Do a trace in the direction your entity is about to move with the vector length being the distance it is about to move. In the trace_mode include the use_box flag. If trace returns a non-zero value you are going to hit something before you have finished your movement - so then do a vec_normalize (movement_vector, result_of_trace);
note that characters won't glide in this case, but just stick. I haven't taken time to work out a means of gliding yet (I just got through writing the code to do the above). Also since I just barely finished I haven't tested it with more than just a few simply blocks and flat wall surfaces and the like, but just an idea that may help you...... basically the whole concept is based upon the 6 day tutorial in the WDL manual where they detect if a entity is standing on the ground or falling. Be aware that you will also need to tweak your min_x, max_x, min_y and max_y values somewhat if you want absolutely no entity overlapping into the walls/objects.

If I understand the undocumented feature mentioned previously in this thread it is essentially doing the same thing (though probably much quicker) and would still have glide options available etc - but then again it is undocumented and may not work for you.....

Well sure, I could write my own collision detection using "trace." But that's incredibly slow, and I'm not referring to the time it would take to write.

a) Trace is a very slow command. For a simple scene, what you describe may be fine. But if there are a decent number of entities to track, doing a trace like that for every entity every frame, buh-bye framerate.

b) While I'm doing my custom collision detection, the built in collision detection would still be taking place! Thus, it's doing all the collision detection calculations TWICE for every entity. Talk about a waste

Note also that the undocumented feature is nothing like what you describe. The undocumented feature seems to be just like collision detection with collision hulls, except that each entity has it's own sized "hull" (its bounding box.)