CGTalk - Material: Gunmetal

gnarlycranium

01-11-2003, 10:49 AM

I have been attempting to make a gun in MAX 4.2. It will be in a scene with raytraced reflections, and it will be a very close up shot. Making the right material is proving to be much more difficult than I was expecting. I've gotten about as far as I can on my own... I'm probably way off track-- I could really use some help!

The difficulty that I am having is that the specular highlights on metal tend to follow the scratches in the surface... and those scratches are in all different directions at once, showing up depending on their orientation to the highlight. I am not trying to make a metal that is brushed in just one direction, but several all at once. If you look closely at a metal surface that comes into contact with things often enough to not be mirror-smooth, you'll find that the highlight tends to have a radial sort of aspect to it. http://www.logrhythms.com/Leah/GMhighlight.jpg
I have yet to find any method of simulating this.

I don't think anistropy or other such specular effects will help, so I'm trying bump mapping. I have used a Mix map to blend two procedural Noise maps together, one stretched horizontally, the other vertically. It's a start towards what I want, but I think I still have a long way to go.

Here's a test, on some random object. There is no scene environment, so I've just slapped the good ol Lakerem bitmap on it for now. If you guys can recommend other ways of displaying the material, go ahead!
http://www.logrhythms.com/Leah/GMtest01.jpg
Raytrace material (Fast Adaptive antialiasing on)
Blinn shader
Diffuse Color Value 40
Specular Level 200
Glossiness 40
Bump 10

gnarlycranium

01-11-2003, 01:15 PM

I mixed the mixed bump map again, rotating it a little each time and tiling it a little finer... this reduced the contrast, so I raised the bump level to 20. Does it look any better?
http://www.logrhythms.com/Leah/GMtest02.jpg

Tumerboy

01-11-2003, 10:38 PM

it looks like good stainless steel, but if this is for a gun, it's rare to see such a shiney gunmetal, or if it is, then it's nickel plated and SUPER shiney. . .

Stahlberg

01-13-2003, 01:17 AM

I know what you mean about the radial effect, it happens with other things too, like ice-covered treebranches against the sun, skate-marks on the ice, scratches on glass, for instance...

the second image seems closer than the first, but I think what you really need, instead of stretched noise, is lots of fine straight lines - full black on full white, all roughly the same thickness - going in lots of different directions. The only way to get this just the way you like it may be to paint it. But you should only need to paint a small part of the first layer, then you can copy/paste the rest.

gnarlycranium

01-17-2003, 07:48 AM

Stahlberg -- This is what the noise bump map looks like right now-- it's 8 different sets of streaks layered over each other at different angles. I know the streaks are white instead of black, but I made the bump level negative, so it's all good. I like the way it looks this way better than a straight black/white contrast, but I'll try both!
http://www.logrhythms.com/Leah/GMnoise01.jpg

Tumerboy -- Stainless steel is too darn easy to make, it's what I always seem to end up with no matter what metal I'm trying to do! :p I'm not sure how much less shiny it should look (I've been having a very hard time finding any good gunmetal reference pictures), but I've tried toning it down some in this try-- though the gun in question is almost certainly nice and shiny and plated and polished, not the dull iron-black look that it would otherwise have. I also have this weird urge to give it a subtle blue tinge, but I'm not sure how... probably a bad idea anyway. :)

http://www.logrhythms.com/Leah/GMtest03.jpg
Specular Level 120
Glossiness 30

I think I need to put this stuff in a scene, reflecting things, to really get an idea of what it looks like-- next test, it'll be on a table! Whee!

gnarlycranium

01-17-2003, 11:22 AM

Well, like I said... here it is... on a table, in the desert.
http://www.logrhythms.com/Leah/GMtest04.jpg

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