scratches and dented marks

[Toonwonder]

Hello all! I know this is basic texturing but for some reason my memory is in a cloud. Can someone tell me how to make dented scatch marks or pot marks in an object.(perhaps pointing me to a good tutorial) the marks need to be actual dents not just the main surfacing illusion.

thank you!

[composermanII]

you might try using the dented, fractal noise, and hetero-terrain proceedural textures. Use them in the bump and diffuse channels and mess around with the scale parameters until they look correct. I hope this helps.

Good Luck,

Troy McClellan

[JulianW]

Hi,

better yet use an image map, its hard to get realistic damage from procedurals. You can either paint one from scratch or base it on a photo of something that has the right sort of feel to it say a seriously distressed piece of concrete.

You need to remember to make the damage show up in a number of surface parameters, for a really nice job remeber to affect:

Bump
Diffuse
Specular and Glossiness
Colour
Reflection

You don't need all of these but it will help make it that bit better. When trying to create the different maps think about the surface properties.

Eg. if its a chrome effect piece of plastic use the image maps to set some parts of the surface to have chrome like attributes in all the channels and plastic like attributes in the damaged areas.

DV Garage (http://www.dvgarage.com/) seems to have gone downhill a little lately, but its still quite a good place to learn about this sort of thing if you don't mind having to register (for free),

hope that helps,


JW.

[Toonwonder]

thanks for the tips! I have a question though. These procedures
only affect the look and not the geometry right? At some point in my training (a lot of good that did me huh?) , I remember applying an image map that actually affected the geometry like scratches or corroded metal holes. Perhaps in Object properties with displacement bump map? I could be wrong though.

[banshee]

Your correct. Only as a displacement will it alter the geometry. A bump map will give an "altered appearance" but the edges will still be nice and smooth, provided it was modeled that way. Specific scratches and details are better left for texture maps. Procedurals can help and a combo could work but maps are the better choice.

[mattclary]

I beg to differ with Julian. The random nature of procedurals make them perfect for this. Follow this link to probably the most handy info I've ever found on this subject.

http://www.3dluvr.com/davewilson/makingof/arach/MakingOfArach.htm

[JulianW]

Hi,

I'm not saying you can't use procedurals matt, but you can run into their limitations pretty quickly. One example is scratches, afaik there is no easy way to create realistic scratches on a surface using a procedural texture.

As I see it when you use procedural textures you can get nice results but it becomes difficult to create truly realistic results where the damage to the surface seems 'motivated'.

The arachnid you linked to is a classic example, really nice texturing but the damage is randomly distributed over the surface, when it would usually be focused on parts which stick out more, whilst grime would build up more in the recesses.

That said procedural textures certainly have there uses its just important to realise that there randomness is not always your ally.

There seems to be a nice (though not too new) tutorial thread on texturing over at CG talk by Leigh van der Byl Here (http://www.cgtalk.com/showthread.php?s=&threadid=6648) which goes into some detail on how to texture, I haven't had time to read it all yet but there looks to be some good stuff in there.

all the best,


JW.

[byte_fx]

Ok - you want to model the actual nooks, crannies, etc - right? While you could export the model to layout, apply some sort of displacement to it and then do a 'save modified' to retain the new shape this would require massive amounts of polys to get the sharp detail you want.
So - why not model the defects? In modeler zoom into the area you want to add defects to. Switch to an empty layer and place the original layer in the background. To add a pockmark draw a sphere a little larger than you want the pockmark to be. Using an approprite view position the sphere so part of it intersects the backgrond layer.Once you're happy with the positioning switch layer's - the apostrophe key - so your main object is now active and the pockmark shape is background. Do a Boolean subtract - there's your pockmarked surface. Don't forget to merge points so future ops will work right. Elongating the sphere parallel to the main poly, applying some jitter, and shaping it with bend, shear, etc will yield a variety of shapes for the pockmarks.
For scratches just use a long, thin shape, etc.
Hope this is what you wanted.

byte_fx

[Matt]

nice link that matt!

while fractals are nice and quick (as the link you posted shows) it does give an un-wanted ''all over nice and even" look (more noticable in the radiosity render at the end)

I know you can use weightmaps to 'localise' the damage to certain areas, but it would be great if LW had a 3D procedural scratches and dinks generator!

anyone care to code it!!! :)

[Matt]

also, you might wanna ask luka more about the settings he used on the image he posted in this thread, it's very well done!

http://vbulletin.newtek.com/showthread.php?s=&threadid=3061

and if he tells you, please tell me!!!

:)