tyre tread dirt ?

[knight42]

I do this with a polygon selecting covering the worn parts, and do a dity rubber material just applies to the selection.

[JamesMK]

A poly selection would probably leave far to obvious borders between clean and dirty material.

A better way might be to paint the vertexes and then use the vertex map to control the alpha of a dirt material placed on top of the rubber material. If you want big chunks of dirt it turns into a different problem however.

[alienesque]

thanks guys :)

i had already tried the poly selection thing already but as you say it gives a far too distinct edge between clean and dirty.

the painting vertex's way would be something ive never done before so ill give it a go...wish me luck ;)

il let you know how it goes

thanks for your time :applause:

[JamesMK]

Here's a really ugly and purely technical example just to show how you can set up the vertex map and so on...

http://web.telia.com/~u48039569/stuff/vmapdirt.c4d

[JamesMK]

Here's a really ugly and purely technical example just to show how you can set up the vertex map and so on...

http://web.telia.com/~u48039569/stuff/vmapdirt.c4d


EDIT: Oh, and yep, good luck! :D

EDIT 2: Anybody else notice how close together the 'quote' and 'edit' buttons are? No?... OK... :blush:

[flyingP]

EDIT 2: Anybody else notice how close together the 'quote' and 'edit' buttons are? No?... OK... :blush:
old age will do that to you :D

[alienesque]

very many thanks

one thing though, ive worked out how to do it but it seems my version of cinema (8.5) doesnt have the brush tool...is this correct?..do i need 9 to use your method?

thanks again for the file..helped me a lot :)

[JamesMK]

one thing though, ive worked out how to do it but it seems my version of cinema (8.5) doesnt have the brush tool...is this correct?..do i need 9 to use your method?
If you mean a brush for vertex painting, it's there in 8.5 too.... don't remember where though...

old age will do that to you :D
Bwaahaa! Yeah, you should know :D

[flyingP]

Bwaahaa! Yeah, you should know :D

touché :)

[alienesque]

hi..sorry to bother you again.....ive got so far but ...in your file..how did you apply the dirt material just to the yellow parts of the vertex map..i cant seem to see how you did it..cheers

also..why did you use a layer in the alpha channel..and why is there an alpha channel at all..shouldnt the vertex painting take care of where the dirt material is seen or not seen?

thanks again..ive learned a lot already..ill give some back to this forum one day..hopefully:)

[JamesMK]

If you look into the layer called Vertex Map in the layer shader in the alpha slot, you'll see that it calls the vertex map (cleverly named 'dirt' in this case :D ) This corresponds to the vertex paint and makes the whole "dirt" material visible (i.e. having full opacity) only where the vertices are painted. The layer thing was just to allow a noise or something else to break things up a little, and the vertex map shader is then put above the noise in multiply mode in order to cancel the noise outside of the painted area.

So, the alpha controls where the "dirt" is applied, and the alpha in turn is controlled by the painted vertex map.

Hope that clears things up a little.

[alienesque]

wow..well..thats some of the best help ive ever had..ive managed it..im not sure i 100% understand it though ;)

ill carry on with it and hopefully everything will become clear..ill post a jpg when im finished..

thanks very much

:thumbsup:

[JamesMK]

You're welcome. And you'll fully grasp it after you've done it a couple of times on your own, no problem. The method as such is very useful quite often.

[rendermania]

This sort of stuff is best done with BodyPaint. It really is a great tool for spraying on stuff like dust and grime with manual control. An alternative method would be to achieve a dirt effect using either the diffusion, bump or displacement (micropoly displacement) channels or a combination thereof.

If you create a layer shader, you can use a gradient to control where and how strongly something like a bumpmap or dirtmap is applied. In the case of a tractor tire, you'd need to use something like cylindrical mapping and create a gradient than only applies bump/dark diffussion to the outer edges of the tire. If you do try the gradient method, use something like 'multiply' or 'screen' to transfer the gradient onto the dirtmap.

[alienesque]

yep..i can imagine using it very often in the future..its working a treat.just take a while to paint all the tread parts

..strange that its not mentioned in the index in the manual though...

:)

[JamesMK]

If you do have BP, seem to remember that you don't, then rendermania's way is of course the best for ultimate control.

[alienesque]

no..i dont have BP..sadly...

this way is great for this use though..perfect..

:)

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.