CompuServe Thread

Yes to both methods. You could either create "skidmark" geometry that would morph in time with the car, or you could create an animated map for decaling, or for texture/opacity mapping onto a "skidmark primitive" object that could also morph or scale to grow in time with the car's progression down the road. There are probably more ways to do this, but you're on the right track both ways. John Tissavary (LUNA cie)

This is strange because I was thinking about the very same thing last night while laying in bed (could I have been doing better things?). One thought might be to create the road with the skid marks already existing, and if this road is a solid color, create a copy of the road (without the skid marks) adn raise it just a fraction above the one with skid marks. When your vehicle "skids" across the road, have the copy slide with it thereby exposing the skid marks underneath. If your road is textured to look like asphalt, then use the same idea as above only (if this can be done in 3-D Studio) have te on the copy road move the opposite direction at the exact opposite speed that the copy is moving (confused yet?) giving the effect that the texture map never really moved at all. Hope this gets ya on the right road 🙂

Let me see if I can remember how I did that, Forgive me if I leave out a step or two, but hopefully you will get the idea. I used AniPro with 3DS. ___MAKING THE OPACITY MAP___ Create a cube the size of the tire patch and place it directly under the skidding tire, then link it to the vehicle. Setup a top view such that only the tire patch is displayed and it moves from edge to edge (in the rendered image), another words it will move completely across the screen from one side to the other. Render the top view as a flc in the same resolution as the finished animation will be. Then in AniPro paint with pure white. Start at frame 1 and paint the entire screen white up thru the tire patch, then frame 2 and so on till all the frames are painted white up thru the tire patch. When you are done you should see the white move across the screen at the same speed as the tire patch did. If the skid does not start till say 60 frames into your animation then just add 60 frames of pure black to the front of you animated opacity map or you could leave out the added frames and use Video Post. Make a material out of this flc using it as an animated opacity map. ___MAKING THE SKID MARK OBJECT___ In the keyframer write down the coordinates from the top view of the tire patch every fifth frame, this depends on the accuracy needed, you may have to do this every 2 or 3 frames. In the shaper create a line (path) using the coordintes for the tire patch. Also create a cube the same size as the tire width. In the lofter, loft the cube along the path such that it is just above the roadway. In the 3D Editor apply the animated opacity map material to the skid mark. Apply the mapping coordinates such that the edges of the icon are on the edges of the skid mark object. This may have to be adjusted alittle bit to get it exact. The closer the tire patch object is to the edges of the rendered image the easier this will be. When you are done the opacity map material will uncover the skid mark as the skidding tire passes over it. Hope that I didn't forget an important step<BG>, if you have any problems just let me know!! Regards…………..Rick – Technical Animations

There is an easier way then all of the previously described ways. Its call "PYTHON", a new ipas aval. from SCHRIBER that lets you "grow" an object along a path. Ive tried it once and it works great for tire skids. -Gregg Daly GRaphix Zone