tire track

# 1 21-10-2003 , 01:10 AM

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don't know if this is the right place for this question, but here goes-

i am trying to create a tire track coming out from under a rotating wheel

have tried using paint effects on path, but cannot find a way of producing my own custom brush in the shape of the tread pattern

anyone got any suggestions

cheers,
tony

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# 2 21-10-2003 , 01:49 AM

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You could always do a gif animation with transparencies and stick it on a plane directly over the ground, but that might get tricky if your ground isn't perfectly flat. Not sure if that would be easy or difficult to do. Also, it would be quite difficult to modify the tire marks if you wanted to change something. Come to think of it, can Maya even import gif's to begin with?

Hmm. Another way would be to make a giant image with the tire marks from start to finish, apply it to a plane, then create another plane with the opacity set to black hole. The "black hole plane" would have to travel over top of your tire track image. You would have to move it to reveal the tire tracks as the vehicle or tire moved along. You would of course, render the tire tracks out, then composite them into your real animation to achieve this effect.

I'm sure there is an easier way to do this though.....

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# 3 21-10-2003 , 01:58 AM

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Let's see here..... another way to do this would be to create many, many very small planes and place them right next to each other in the path of the tire(s). You would have to animate the transparency or visibility for each face so that the tracks seem to appear as the tire rolls over them.

I believe you could also just create a big long plane, apply your tracks image to it, then map a ramp to the transparency or something and have it so the white=transparency and black=zero transparency. You would then animate the little bar things on the actual ramp so that your transparency follows the tire according to your animation. I'm not entirely sure if you could really do this since I haven't done this particular thing before, but it should work.

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# 4 21-10-2003 , 02:05 AM

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oooo oooo! Another way would be to actually make the tire tracks in 3D with planes. (easily done) All you would have to do is place them directly below the spot you wanted them to appear at and animate them so they move up at the correct time. This may or may not work depending on what effect exactly you are looking for. I'm sure you could write some sort of script to make the 3D tracks appear behind your tire as it moves along. It is also possible that you could place them all in their respective places like the example I provided two paragraphs ago and have the script change their transparencies as it comes close to (or practically in contact with) the tracks. This is way over my head though.

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# 5 21-10-2003 , 02:26 AM

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lol. Im sure he is glad you have written him three novels there. lol. Ask Brian.

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# 6 21-10-2003 , 04:30 AM

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heh, well I kept thinking of more and more ways to do the same thing, so I had to post them. lol. And yes, maybe Brian has some tricks up his sleeve. He did a jeep model a while back with some realistic pivoting animation for the wheels and has done some really magnificent vehicle modeling in his time.

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# 7 21-10-2003 , 12:21 PM

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If youre track on the tire is 3D, then you could use a softbody ground and acutally have the tire making the impression!

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# 8 21-10-2003 , 04:10 PM

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thanks for the response guys - so many ways!

i haven't had a chance to try anything yet, but i like the idea of just laying down the tread pattern on a surface and just revealing it using the transparency node - if i can figure that one out

the tire uses a bump map for the tread, so getting it to leave an indentation would just leave a flat groove (i think)

at the moment, i have rendered out the tread trail as a separate file with alpha, and am now rendering the main animation without the track - then i'll comp them together in after effects, using a mask to hide the bit in front of the tire

this seems to be the easiest way for me at the moment, as i still get a bit confused by the hundreds of ooptions in maya

by the way does anyone have any input on the custom brush thing? - that would seem like a cool way to do it if the tread pattern could be made in to a maya paint brush, then it would be quite easy to animate the brush on a path

will post result of comp when done

cheers,
tony

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