From the results in this thread on displacment mapping a tire tread, Martin suggested that I model the tread...

So I did...

Modeled Tire Tread Tutorial:

Two ways to get your initial pattern.

1. Rotoscope in A:M and model over it then extrude it and cap the top.

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2. Draw the pattern in Adobe Illustrator or something that can export AI files and import it into A:M and extrude that. (May require cleanup to lower the patch count)

Next: When you extrude it extrude a half inch. I was trying to build my tire to scale, so half inch is probably too deep, but it gets the point across at the deepest channel in the tire.

NOTE: If you wish your tread to be round like the tire, you will have to adjust the CPs on the outside edge so they follow the arc of the tire BEFORE you duplicate them.

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Group your 1 row of tire tread pattern, name it and either save it off or move it out of your way.

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Next trace your tire profile with a cut in it for your tread to sit in.

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Lathe out your profile with a lathe cross section count set to 8.

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Select your tire tread and use the 'Lock CPs' button to keep you from accidently changing the base tire shape.

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Move your group onto one of the axis points and orient it properly to the tire.

Select the group manually by dragging a bounding box around it.

Goto the properties of this new untitled group and set the pivot to 0, 0, 0.

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Now right click on the group in the modeling window and select 'plug-ins->Wizards->Duplicator'

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I had not rotated or changed my tire position since lathing it, so here are my settings.

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Set it to 'Copy', Number of copies = 48, Rotate around the 'Y' axis by 7.5 degrees. Then click okay and wait... be patient, it will take some time for your tire tread to duplicate 48 times around that axis.

Once you are done, you should have something similar to this.

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Hope this is of some use. CHEERS!

That's very nice - the displacement map version did look as if it had come out of a cheap mold, which had its own charm.

Care to say what the render times were compared to the displacement map version? Martin did say this approach should be a lot faster.

Apropos tyres... I was thinking about tyres recently, as I shall have to work on my own soon. In particular, I plan to play around with distortion boxes such that as the vehicle weight bears down on the tyre, the tyre compresses and bulges where it meets the floor regardless of the rotation of the tyre. Your displacement map thread prompts the question (to me, at least): do displacement map displacements respect distortion boxes? If not, the discrete approach has further advantages over the displacement approach.

So how many patches are there per tire??
David

Stuart, this rendered WAY faster than displacement maps, just as Martin said.

David, that's the problem, it's quite high (14720 patches for one tire). I'm sure it could be much less by simplifying the tread pattern geometry.

It would be much easier to simply make a bitmap like my guide pattern and apply it as a simple texture map for basics.

This tutorial was mainly for those who do still beauty shots of autos. Especially one of a 3/4 view with a close up of the front wheel turned out.

Just a thought...

Now that you have the tread modeled, how would it look if you rendered a normal map of the tread and applied that to displace your primitive tire shape. You may have to add some bevels though.

From what I've read..."The normal map should extract detail from the high-resolution version and apply that detail to the low-resolution version so that both look identical."

An I thought we were "all that" when we added bump maps to tires....

David

TheKamps,

I have yet to play with normal maps. I think they would work fine with moving tires/wheels although with a render hit.

Again, this tutorial is primarily targeted for folks that do the 'money shot' stills with automobiles.

It can be applied toward any cylindrical item with detail that repeats really though.

ddustin,

I've done the bump map thing with tires. If they are moving and at some distance, even that is not necessary. Simple color maps will work wonders.

Normal maps are just bump maps that use another data encoding approach. But they are really just another file format for bump maps. It will not displace the surface so there is no render hit from using them.


No, The normal map only contains normal orientation information. It does not "extract" anything. You need an application that will do that.

Personally, I think normal maps are not very usefull. You cannot paint a normal map like you can paint a bump map. And transforming a bump map into a normal map will gain absolutely nothing.

Plus, a bump map contains displacement information while a normal map contains no displacement information. Although some applications claim that their normal maps do displacement, it is only because they actually use the blue channel to add the displacement (bump map) information.

There exist some applications that can take a high resolution model and split it into a low resolution model plus a normal map. Those applications could just as well split the high resolution model into a low resolution model and a bump map and produce the same end result.

The only advantage of using normal maps vs bump maps is because rendering a normal map requires a little less calculations and thus should render slightly faster. The reality is that it is so slightly faster that the difference is unnoticeable.

Wow, yet another set of facts I didn't know.

Thanks Yves!