Watch some gameplay videos of this game called spin tires: http://www.oovee.co.uk/games/upcoming-games/spin-tires/ I've tried the demo and I got bored pretty fast but there was a few things in there that I liked so I guess I could just leave it in here for the devs to see to get some inspiration. 1. The voxel based deformations on the ground. You sink into the earth and have to put on all of the dif-locks to get out of some muddy places was awesome, though a bit buggy at times. It would also create small rocks that you dug up when trying to get out of the hole you sunk in to. 2. They have some awesome textures for procedural tire dirt and wet maps where you actually can see that the dirt gets stuck in the tire treads filling it up. I don't know if the tires get less grip during that effect, but it would be nice if you could add it if possible. 3. The particle system for the dirt being thrown up from the tires was pretty good. 4. I actually liked the way you shift gears in that game. You have a graphical shifter that you would have to use your mouse to shift in to when holding in a "button-press". I guess the UI could change for this depending on what car you made. A tricky UI would make for longer shifts, and a H shifter would obviously make for fast gear changes. Is voxel based deformation possible on the landscape in the torgue engine?
I like the idea. If I may have some input, if the tyre tread fills up with mud there shouldn't be a difference to the performance of the tyre. We all know that slicks are immensely grippy because they have a greater surface area in regards to the mating surfaces between road and tyre. But mud being as fragile as it is shouldn't make a difference. that said, I think deformation similar to the terrain Deformation seen in Sega Rally would work better. You have a high density mesh on the track and that deforms instead. It looks alot better than the voxel thing going on in Spin Tires. It looks like you deformed the mud, rather than turn it into rocks.
Slicks and tyres with mud isn't exactly the same thing though, hehe. Driving a car with mud and sand on its tyres will be just like driving on gravel until the stuff are flung out from the tire. So no, mud and sand and the like in the tire tread equals to less grip, much less grip. I took a look at the tech demo of the Sega Rally surface deformation now, and it does't look like it affects the car that much. So my guess is it deforms by just adding normal/hight maps to the shaders and not the actual terrain it self? I may be wrong of course.
if you read what I said, i basically explained that while the mud filled in the gaps of the tread and increased the surface area, it doesn't make a difference to your grip because its so fragile in comparison to the tyre. At best you might get a slight lubricating effect from running over the mud thats flying off your wheels. The Sega rally deformation does have an effect on the handling. if you watch the demo and pay attention you see that it also deforms the collision mesh associated with the road surface, they have a segment where they demonstrate the car rolling slowly over some chewed up mud. They talk about how you'd search for tyre marks in the game because they offer a little more traction, and they're right. When I play it I do search for tyre marks because there is a bit of an advantage to following grooves in the road surface and the grip afforded by not having to trample fresh tracks in the snow.
I don't quite get what you're saying. Are you saying that a tire with treads with mud in it, is as good as slicks tires? Any tire with any amount if dirt/mud/sand on it will always be worse than a clean tire on tarmac. And a tire where mud and sand is stuck in the treads are worse then a clean tire in sand/mud/dirt.
I'm saying that it doesn't seem to make too much difference. I was just writing from a point of view of intuition. It makes sense that if you fill in the tyre treads with a material you gain surface area and gain grip. Say I drove over some rubber, the weight of my car squashed the rubber and got the rubber stuck in my tyre treads. The rubber has filled in the gaps in my tyre and increased the surface area of the tyre and therefore my grip, at-least until it falls out. However, mud crumbles and doesn't offer any extra grip therefore there shouldn't be any difference in terms of handling. it hasn't changed the tyre, there's just a bit of mud stuck in the tread that isn't doing anything. That is all I was saying. The surface you drive on is far more important, dirty tarmac is more of a hindrance than a dirty tyre.
