How do I create custom vehicles?

I am designing a map that will need custom vehicles in it. (It's going to be a race track of sorts, not a TF2 map.) I want to know a few things.

1. How do I program the motion of the vehicle, such as speed, acceleration, braking, turning, etc.

2. How do I create a custom model for the vehicle?

3. Is there any way to get it to stick to walls without regards to physics, but still have the vehicle fall if not on a wall, like when it goes off a jump?

I would very much appreciate the help. Thank you!

hl rally, a great racing mod for hl1, had a bunch of really good coders and modellers. They tried really hard to make a hl2 version, but gave up after finding out that the havok physics engine that hl2 uses was unable to support or handle the amount of physics data that would need to be processed.

for the sake of your own long term sanity, come up with a different map to make.

No, I just want this car to go really fast. It doesn't have to stick to walls, that's just something I hope to put in.

You say this isn't for tf2, which is good, because tf2 (or any other source multiplayer game, afaik) doesn't support drivable vehicles like the buggy from hl2 or the car from ep2.
Does this mean you're planning to do this for singleplayer?

Don't do the vehicle thing. All you can do is create a big moving brush that will lag the hell out of anyone with > 50 ping.

Quote:
No, I'm actually planning to model my own car (using milkshape or something) and then program the speed and stuff. I realized that you can't make cars AFAIK in hammer that are driveable. You can spawn them but you can't design them. (As in their speed and such. You can add brushes to them but that's about it.)

That's what I said. Your car will just be a big brush, right? Or a model, or whatever - either way, it'll be totally server-side and players with 50+ ping will glitch all over it.

I don't think so. This is going to be in garrysmod where it is possible to have 2 different people drive 2 different vehicles at once. It's going to be built the same way the airboat or buggy was built, and I've never had a lag problem with those...

And the reason that it's going to be in garrysmod is because it has a HL2 base.

Ah, ok. I didn't think that those were supported in tf2, and I didn't know you could do multiplayer garrysmod!  

Quote:
Oh yes, you can go online and play with others. It's a lot of fun as long as none of them are mingebags. (Gmod term there)