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myself44
05-16-2007, 09:57 PM
Hi, I'm a 6 months beginner in Maya.
So far, learning modeling ... was ok. Texturing ... not bad but need practise, Lighting ... a real pain. Rendering ... I got owned. But all those thing, I can do pretty good now.

Only one thing : Materials.

Im my scenes (let's say interior ones), I want to apply realistic (to a minimum) materials. I want sofa to look like leather. I want chair to look like wood. I want lamp to look like metal.
I've seen a lot of tutorials, read a lot of book, but all of them keep saying stuff like : blinn is good for metal , phong is nice for chrome, etc.
BUt... HOW ? What settings to tweak ?

Example, I tried quickly to create different look for 4 cubes : (in order left to right, up to down)
- plastic - wood -
- leather - metal -

http://i14.photobucket.com/albums/a350/myself-44/mat.jpg

Have a good laugh, then, could someone help me how to acheive realistic materials? I just dont know how to make real metal, real plastic, real leather, etc. Whatever material I apply and tweak (blinn, lambert, etc.) it always look pretty much the same.

Guidelines, advices, anything!
The best gift would be a scene with some cubes already some reailstic materials applied :)

thx in advance

btw, I use Maya 7, or 8 or 8.5 wont work for me. sry

PS: why when I try to batch render a file in PNG, there's an error in the file and no viwer can open it. The only format I can use now is Tiff and Jpeg... wierd

hakanpersson
05-16-2007, 11:16 PM
I dont think you can simulate those material with just shaders. Blinn should be fairly easy to tweak without a tutorial. And if you want it more complicated you should go for mental ray or similiar (sure theres handbooks for those). Otherwise id try texturingtutorials. Check 3dtotal.com, there should be plenty tutorials for texturing and shaders.

victor
05-17-2007, 04:24 AM
Making materials isn't about learning what the right settings are for leather or wood or whatever. It's about understanding what effect the various components of the material have on it's perception and why.

What color is the material? How shiny is it? Is it coated with something? Is it smooth or rough? Is it painted, and if so, shouldn't you be making paint instead of the surface below?

In you case...

First off, start with something other than cubes. With basic lighting, they just don't convey enough information. How a surface appears depends on how it reacts to light in may different directions. Two or three flat sides and a slim round edge don't do much more than give hints.

The materials you chose are good examples:

Plastic is simple. The reason so much CG looks like plastic is because it generally has a base color and tight white highlights due to how the color is actually inside/below a clear smooth surface.

Wood generally shouldn't have highlights, but relies on the diffuse color to be convincing. You need a texture. If it's coated, you need to consider that for the highlights. A clear shiny coat would have white ones. If not for the color of the grain, my would floor could be plastic. Bump is important too. Highlights and reflections on most wood surfaces are diffused by the roughness of the wood grain. In some cases that isn't so, but even in reality, the wood starts to look like something else when that happens.

Metal is different in that its color is throughout (unless of course it's painted, in which case you should be thinking about the paint instead of the metal). It will have highlights that are the same color as the metal itself, and reflections that are tinted the same. If it's rough, wide highlight. If it's smooth, very tight. Reflections will be very important in this case.

Leather, I'm not so sure about, but I'd think it would be a cross between plastic and wood, in that you want a tight white highlight if it's smooth and finished somehow (none if it's not), but that you'd need some bump to be convincing.

Edit: OK, here's 15 minutes of materials from scratch using Maya textures (don't complain). Nothing amazing, but maybe it's a starting point...

myself44
05-17-2007, 09:22 PM
Edit: OK, here's 15 minutes of materials from scratch using Maya textures (don't complain). Nothing amazing, but maybe it's a starting point...

Why should I complain, thx for taking time to do this !
But are you telling that Maya textures is not enough to create some realistic texturing ? Cause I tried a few mentalray materials and it takes forever to render.

Here's an litttle example of what I try to acheive. Look the post of R. Mutt (bottom of the page). Look the metal of the chair, and the black leather or the seat beside the window, this is what Im actually aiming at.

http://forums.cgsociety.org/showthread.php?f=87&t=482215&page=3

thx again for the scene! :)

techmage
05-18-2007, 12:15 AM
When it comes to high shine metals, like the chrome on that chair, the actual material properties are only half of it. Set fairly high relectivity, a mid to sharp highlight on a blinn, maybe some anisotropy if you want to get fancy. But with all those set perfect your only going to have a shiny grey sphere until you get it to start reflecting something. Which is where the rest of convincing metal comes in, you have to take care to set up what it will reflect. Now when your doing realistic interior archviz you have the luxury of super hot spots where the windows are, these make really bright reflections in the metal which gives it that high luster look that is associated with chrome. But what your trying to do in your test scene there with metal is more like what you would do when setting up product shots, which how to set up good lighting and enviroments for products to reflect is a whole proffesion in itself. Usually you want to have atleast a cube encompassing your metal object with a white area light above it pointing down that gets its light to the corners of the floor so then it has the potential to reflect the high contrast line between the lit floor and the less lit wall. That is at minumum though. Usually to make convincing chrome in a product shot style I like to make a number of really tall, mid-width area light and position maybe 4 of them around the object in completely arbitrary positions and angles to get the specular highlights and the sharp edges in the reflections to add to the flow of the composition.

As for leather, you could do it with phong, maybe fiddle with phong E. The only thing I think leather must have is a highly rolled off, light and wide specular highlight.

victor
05-18-2007, 04:21 AM
Why should I complain, thx for taking time to do this !
But are you telling that Maya textures is not enough to create some realistic texturing ? Cause I tried a few mentalray materials and it takes forever to render.
By "Maya textures" I was just referring to Maya's very basic built-in leather and wood shaders that I used to keep the attachment small. Usually, you would want to use images as texture maps when trying to mimic realistic wood or leather wrinkles or cracks.

Also, I should have put more emphasis on environments. There is no way you will get chrome to be easily recognizable in an all white or black scene. The material itself has no real appearance of its own. It just reflects everything around it, and even then it's important to either see enough of the environment in it or see it in motion to be convincing. As for the leather, If you want to go beyond the basics above, you will probably want to give it a slight but very blurry reflection. Black leather has practically no color of it's own either, and relies on bright lights or objects to reflect off it in a very diffuse way.

victor
05-18-2007, 04:28 AM
double post.........

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