Texturing Cog Tags

[soulburn3d]

That's basically blurry metal, with a stronger bump map. This may help...

http://www.neilblevins.com/cg_education/chrome/chrome.htm

It uses Brazil, but the theory can be applied to any renderer. Or if you want to use mentalray, you could also just look for a similar material here...

http://www.mrmaterials.com/

And don't forget to keep this in mind, since your objects are primarily flat...

http://www.neilblevins.com/cg_education/flat_metallic_surfaces/flat_metallic_surfaces.htm

- Neil

[sundialsvc4]

This is a game of "surface characteristics" and "color temperatures."

Look at the light. Measure RGB values from the reference image. Take a histogram of the shape.

You see that there are actually several layers of different light-effects going on here. Start with the bare metal: get the colors right, the base specularity and so forth, and perhaps most importantly, the color-temperature of the lights. Get a perfect rendition of the smoothly un-machined material.

Now the lettering: a separate object, with a separate material for the ink. Get the perfect fresh-from-the-inkpot color, and for now, stencil it on the freshly-made surface.

Next step: engraving. A bump-mapping layer is added to the growing render-chain.

Next step: finish manufacturing. Presumably some kind of abrasive wheel was used in the factory. Emulate that. Did it happen before the lettering was stamped in, or after? You decide, and wire-up the chain accordingly. You might need a "halo" mask over the lettering because the abrasive-wheel would have etched the top edges of the letters but not all of them.

Now: age. Scratches and bumps and sticky dirt stuck onto the surface. Develop these one at a time and wire them into the render-chain with "knobs" that will allow you to dial them up or down. Don't forget the letters; handle them separately, at least at first.

Check your lighting and the color of your lights, then start tweaking the textures. Hopefully your software lets you do that in real-time if, say, you've rendered the basic pristine objects and all of the maps ahead of time. (When you've got the "mix-down" just the way you want it, you can replace the pre-made maps with the algorithm nodes that originally produced them.)

The histogram of the CG rendering should be close to that of the reference shot, and mostly bell-shaped. Avoid opaque shadows and blown-out whites. (Channel the ghost of Ansel Adams.)

Notice that I have described:
A workflow of "successive refinement." You get one thing at a time really-right, knowing that it all comes together (only) at the end. A data processing sequence consisting of many distinct "nodes" (a.k.a. "passes"). A great deal of creative experimentation in how you "wire up" those nodes. Arrange things so that you can do the "mix-down" tweaking without lengthy delays. "The picture is really made in the darkroom, not in the camera." Post to the Gallery section of your favorite site(s) for :bowdown: Bask in the limelight, then get back to work.

[phix314]

sundial- you crack me up. You give good tips but damn... so theatrical. Sounds like a Bob Ross infomercial.

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