Graphically, the addition of bumpmaps could add this effect easily. Although adding bumpmaps will not, lol.

Physical effects to the dirt as people drive on them, will add a considerable amount of polygons on road surfaces as people drive on them.

OR, the addition of thousands of polygons on the road surfaces without cars driving on them, and to have them mold as people drive over them to form tire tracks.

Either way, your asking for some serious lag for people without 128-256mb video cards.

There could be another way to simplify. Instead of tred marks, the tire trail is darker, and has a darker side to it, to form a "shadow" like wall to it to make a 3d representation. Also a lighter side. Almost like bump mapping. Then, have the tire tracks made on rallycross roads have parameters to affect the physics of the vehicles passing over them, to simulate "bumps", or if you slide over some tracks going sideways, to bump your car and cause your car to flip, depending on the speed and how deep the track.



It's alot of work, I honestly think it would make me drive in the rally races though, for the time being I find it much more fun driving on a road.

Quote from L(Oo)ney :

We have deformable cars, which is pretty much the type of system needed to make this, i think.

"All" that needs to be done, is to add this same deforming system used to crumple the cars onto the mud sections. When a wheel travels over it, you deform the "mud" and you make ruts.

For simply visual purposes though, a custom height map would work fine to add some "pre made" ruts onto the track.

Cars are higher poly models than the track (methinks), so tire ruts wouldn't look that good in whatever the area was, it would just cause the ground to sink. If the road was higher poly, this idea would work just fine.

for a quick solution bump/shadowmaps (possibly dynamically genereated sort of like the way doom does) + changing the splines (or whatever lfs uses) the cars drive on should do the trick
wont look particularly good for large deformations but you will get the idea what the dirt looks like

From what I've seen, the developers have kept the tracks relatively low on their polygon count. Although, the tracks, almost certainly have more polygons than the cars. I have not seen a wireframe of either, I just use good judgment to make that asessment.

I guess this would have to be turned off in hotllapping mode, though. Otherwise you'd probably see people spending like half an hour to remodel the whole thing.

it needs to be there // dirt without marks is like street without skidmarks :P

+1 for this one.

Would be hard to do - I think the live changes to mapping might draw a lot of CPU time. And I don't think it'd work too well with just a texture change, because we'd all be expecting the force feedback of a proper indentation and that wouldn't be calculated properly without it.

But I'm all for this as a feature.

+1 from me to

Quote from Dajmin :

+1 for this one.

Would be hard to do - I think the live changes to mapping might draw a lot of CPU time. And I don't think it'd work too well with just a texture change, because we'd all be expecting the force feedback of a proper indentation and that wouldn't be calculated properly without it.

But I'm all for this as a feature.

In DX9 it can easily be done with normal mapping. I don't have any easy solutions for DX8

So...who's gonna volunteer to tell the guys they need to rewrite the engine for DX9 then?

Quote :

"All" that needs to be done, is to add this same deforming system used to crumple the cars onto the mud sections. When a wheel travels over it, you deform the "mud" and you make ruts

Think of a game like Simcity 4 (and many others) - where people use 'brushes' to raise and sink geometry to create mountains or create valley's, etc. Maybe on every wheel of every car (at the point of surface contact)- there could be an invisible 'brush' which over time and dependending on the surface (more pronounced for mud, less so for grass and dirt, no effect on tarmac) - the brushes created (or painted) a realistic kind of depression in the ground. I don't know how viable this approach would be when applied to simracing - but today's computers seem pretty able to chop through the calculations when it comes to realtime terrain editing..

I'm afraid the visual part would be restricted to shader tricks like normal or even parallax mapping. Additionally to that you could change the collision mesh by a limited amount so it has an actual effect on the physics, but breaking up the road polygons to display the deformation 1:1 is a no-no in my book. I mean, you probably could do it, but only high end PC's would be able to handle the ungodly amounts of polygons rallyX would create. I don't think that's what you want.

E: Also you cannot compare SimCity like tile-grids with a 3D environment. If you were to split up the track into tiles small enough not to look completely out of place, then not even the best graphics cards could handle that.

Lets say for example, one stretched part in the middle of a rallyX track, is maybe 6*1m = 6m² big. That's two triangles forming the polygon - if there is a bit more detail then maybe 10 triangles or so.
Okay, so what would be an acceptable tile size? Maybe half a tyre width. So lets approximate about 20cm/2 = 10cm * 10cm = 100cm² per tile. We do only simple deformation so lets say one tile = 2 triangles (could be 4 also, for more detailed deformation). Now what was previously two to ten triangles, suddenly becomes: 6m² / 100cm² = 600 tiles * 2 = 1200 triangles. I hope you get the idea why this is not possible this way.

Maybe the visual deformation should be bumpmapped, and the collision mesh changed according to the bump map?

That's what I said :rolleyes:

But these are techniques (bump mapping and parallax mapping) which are used primarily to raise surfaces, not to lower them. Actually, I imagine you could use parallax mapping and it might 'look' good, but I fail to see how simple bump mapped texturing could work...

edit : And just having some texture 'effect' then adding some kind of canned collision detection to go along with it, seems to me to be against the spirit of a game like LFS. The devs are at pains working to create relatively sophisticated models of real-life processes. A stick-on hole in the ground doesn't really fit the vision imo...

But I admit it would be better than nothing

Yeah, I guess bump mapping wouldn't be suited after all, as it only really works on steep viewing angles (which you rarely have while racing).

I saw an example of this done a few years back on a "professional" level driving simulator for engineering use. If I recall correctly, they used parallax mapping to create the effect. It looked quite good actually and I was really impressed with it. This worked great on mud, dirt, and snow, and you could have an unlimited number of tire tracks through it all. If I can find the videos again I'll post them here. This was done before shaders were around, if I'm not mistaken, so today it could probably be done quite well with the newer graphics card technologies of the past few years.

Once you've done it with parralax mapping, you can most likely then read the depression information as the tire drives over the ruts, then alter the collision point(s) of the tire so the tire dives down into the rut a bit when you run through it. So the visual aspect is a bit of an illusion/trick (a rather convincing one, actually), while the physics reaction to the ruts could be done quite properly as well.

Doing the same thing with multiple polys might be a stretch due to the shear number of polys that might be needed. It might be fast enough to do this in a shader, but then you don't have access to the altered vertices (as they're pushed downward when you run over them) so it'd be a bit tricky to make the car react to the ruts. Parallax mapping is probably the best way to go, but I'm no graphics guru. Scawen could school me on that with no problem and I'd happily listen

doesnt use lfs some kind of spline surface that hasnt necessarily got much to do with what we see in game ?

if so you dont need the info from the graphical representation its the other way round

Well, yes, the polygons you see rendered are not used for the actual collision mesh. The latter one is very similar to the rendered surface, but for example all the bumps in grass, mud and sand are only present on the hidden mesh (AFAIK).

exactly my point so you dont have to read collision info from the parallax mappings but directly from the slpines
which btw are by nature very easy to manipulate (which will be a bitch to keep synched in an online game though)

You're not going to have any control over ruts and so on using splines. You could still do the parallax bit on top of it though.

Quote from jtw62074 :

You're not going to have any control over ruts and so on using splines. You could still do the parallax bit on top of it though.

why not ? all it takes is moving a few points that make up the spline maybe add a few if you need a sharper edge ... instant ruts

And you're going to control their location, how? Usually a spline system consists of a handful of splines, so you can go ahead and ripple up the area a bit here and there, but you're not going to have 50 different ruts all precisely placed where you want them.

hahaha, yeah

I want this as a car option...

Quote from jtw62074 :

...
If I can find the videos again I'll post them here.
...

Still waiting