Creating Physics Models for Curved Pieces (3DS Max)

[gerhard2202]

If anybody here plays Garry's Mod, I'm working on a gamemode for it with another guy and my job is to do models. I'm fairly new at this but I'm picking up the artistic aspects of it rather quickly. Where I get hung up is doing physics models. I've read around and lurked a bit and it seems that the only real way to do it is to either construct a version of your model made of convex pieces or have constructed your model in such a way that it's made of convex Elements. This is the piece that I'm learning off of, as I've used the construction method for a straight one:



Is there a way that I can either:
A) Convert this into convex objects
B) Do something with it so that it is made out of convex Elements

Me being able to do this time-efficiently is a key part of our development so if anyone can offer tips, tricks, or other help that would help me do this in the fastest way possible, that'd be great.

[Gambini]

The physic model should be made of convex pieces not merged between eachother; each one with a different smoothing group and with an UV projection (any, it wont be visible). But the most important fact comes now: It has to be simplest as possible. Check some models from the game with the model viewer and look at the collision mesh. A barrel with 16 sides will most likely have a collision mesh of 8 sides, a simple bottle will have a cone at the top instead its complex neck. The only purpose this model serves is to detect collisions with other elements of the game world so you will hardly notice the differences between refmodel and physmodel. Also, it helps the performance and avoids overcalculations in the physics engine.

This is how your collision mesh should look like. I assumed you don´t need concave collisions in the interior of the object.

[gerhard2202]

I do need the concave; the piece is to be part of a race track. Additionally, I can confirm that a high level of complexity in the physics model is acceptable in this situation as these props will be frozen in place and the only collisions taking place will be a small number of balls within the track pieces.

[Gambini]

I thought it was a sort of a cut pipe or something like that. If the track is big enough, and you really need full precise collisions I´d go with an operator to split that mesh into all the faces (preferably only the ones that are part of the track) and then extrude a piece out of all of them.

[kraid]

In this case, i'd create another version of this pipe shape with less faces or melt 2x2 or 3x2 faces of the inner part into one face.

Disconnect and extrude every face to get a convex piece.

Or you could simply use the displacement tool in Hammer with subdevide to create all these pipes much faster and with a per vertex collision.

[gerhard2202]

Thanks, both of you. I'll give the extruding trick a shot.

[marks]

Copy your prop model (ctrl + V) then delete all the faces you DONT want to be collision geo. Select (in editable poly) all the polygons, Break. Then Extrude them all by a small negative value. Set up the smoothing groups and export - should do the trick.

[poisonic]

some magic what you want is not imposible but becarefull of not using to much unique smooting id's
if you need a bit of help ask
you make me curious what kind of mod do you want to make ? i expirimented allot in complex shapes like you describe
especialy the balls & tracks took my atention!!

the last pic was my first try back then i could not model what i wanted 6 years old memory
ATM im bussy with new transulent light emiting banners to spice my idea up

Another note if you have not so much curves in your tracks you could think about brushing it but models are more rewarding at the end