Adding grunge to a mirror surface?

# 1 05-02-2007 , 07:47 PM

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How do I add grunge/ cracks to the mirrored surface below? As to create the mirrored effect I have set the colour to black, so how would I do this as a texture? if that makes sense.

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# 2 05-02-2007 , 08:40 PM

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Sure does make sense.

It's not that much of a prob, though I must admit, with the myriad of options to be had, I must have just got lucky this time..

What you need is a Layered Shader. You need to add at least two materials to it, I guess you could use a seperate material for the cracks and a seperate material for the grunge and crap.

You want to use an image with transparency, the cracks and grunge being coloured and opaque. I assigned this image to both the colour and the transparency channels of a lambert.

You also need your standard mirror shader, blinn, whatever.

After you've got these two shaders, make a layered shader with the cracks shader on the left and the mirror shader on the right (of the Layered Shader Attributes) section as seen in the attribute editor. I guess you could use two seperate images for the cracks - 1 coloured and 1 black and white transparency-map. I haven't bothered to check if it makes that much of a difference to the finished image.

Here's what I got when I applied these settings.
I can send the scene if this isn't very clear.

Edit: Nice image btw, I guess I shouldn't ask what a nice lady like that is doing in the gents? user added image

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Last edited by enhzflep; 05-02-2007 at 08:43 PM.

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# 3 05-02-2007 , 08:56 PM

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That is sweet! I'll give that a try after I have my tea. Thanks for taking the time to do that enhz really appreaciated. I am a complete noob with shaders so this will help massively. BTW, the scene is for a game demo I'm currently 3/4 of the way through and the character is just a reference from a previous scene.

If you believe in telekinesis, raise my right hand.

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# 4 05-02-2007 , 09:05 PM

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:bandit:
Cool Mate, glad you like. I just learned a new trick too, so thanks for that. Looks like we both win.

Problem solving - Oh YEAH!, bring it on.
Creativity - er, um - I think you got the wrong number, that's not me..

Ah-hah!, game eh? Reminds me of a few scenes from DukeNuem3D... Ah, fond memories.

Simon

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# 5 05-02-2007 , 09:44 PM

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mate, that worked a treat, thanks. Just a quick test.

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# 6 05-02-2007 , 11:49 PM

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Cool Magool,

Lookin' great. I know at least 2 people with a smile on their dials. Thanx heaps for showing us the test render.

Waaay better than my crud..

S.

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# 7 06-02-2007 , 09:10 AM

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Yeah for Beet up, grunge, mud, oxidised and other rubbish layered shaders are the way to go!

BTW on a side note if you ever need dust you can use map a sampler info node to a ramp then into the incandesecne node of the material, that way you get more dust as the angle ofthe camera moves further to 180 degrees.

"No pressure, no diamonds" Thomas Carlyle

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# 8 06-02-2007 , 11:40 AM

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Honestly gster, I've read- and re-read what you've said but I don't follow. Adding dust/grime would also be another thing on my to do list. What is a sampler info node? I don't have Maya hear with me to try it out, I really need to get knee deep with shaders as this is the first time I have/will be using them and tbh I am really in the dark with them.

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# 9 06-02-2007 , 11:59 AM

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Out of the help files for a sampler info node

"Provides you with information about each point on a surface as it is being sampled, or calculated, for rendering purposes. Sampler Info can give you information about a point’s position in space, its orientation and tangency, and its location relative to the camera."

If you Plug the facing ratio into a ramp then play with the colours on the ramp thats then attached to a material it adjusts the colour (if that what you want) so that you see more (of less depending on how you set the ramp up) of the colour as the material "bends away" from the camera.

It sets up a fresnell effect, like when you walk past a building made of glass, as your walking down the street it looks totaly reflective but if you look straight as the glass its transparant, it sets that up usingthe cameera as your eyes so to speak.

Dust kind of works the same as you look at dust from an angle you can see it, as straight on it looks normal (depending on how dusty it is) if you use the incandesance channel of a material with a dusty colour or texture (defined on the ramp) you can get it looking like dust etc.

Hope this helps a bit.

"No pressure, no diamonds" Thomas Carlyle

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