View Full Version : Why even use mentalray shaders?

02 February 2005, 02:53 PM
Ok, to be honest here, I've used mainly all my time since i converted to maya from max 2 years ago to learn more about modeling and modelingworkflow in maya and has only used the last couple of months in researching texturing and rendering!

Now, I nearly always render in mental ray for maya and I was wondering if someone please could help me point in a direction to where I can read up on what the advantages on using MR's very own shaders are?

What are the arguments and how do I start toying around with them?

Any reply even slightly helpfull will be gratly appreciated :D

02 February 2005, 05:23 PM
Someone like Jozvex can probably answer your question better (I think he/she has a FAQ somewhere), but my understanding of this is that if physically accurate light, photon, lens, etc. behaviors are what you want, then you should use MR's own physically accurate shaders. But you can use Maya shaders to render in MR, it's fine just not "physically accurate" in the same sense. Basically if you are looking to take advantage of MR's special capabilities, then it's best to use MR shaders.

02 February 2005, 09:11 PM
Use the Maya shaders with Mentalray until you find they arenīt enough for you.
Then start adding the MR shaders you need.

02 February 2005, 09:34 PM

My Mental Ray FAQ is over on the Maya forum at 3DBuzz:

The main reason why you would want to use Mental Ray shaders is for added rendering ability. There are quite a lot of free MR shaders avaible for Maya now that do everything from diffraction, subsurface scattering, occlusion, lens distortion, shader layering with photoshops blend modes, new procedural textures, skin texturing, add more control to GI/FG, etc etc.

There are shaders for just about everything! And that's a huge strength of Mental Ray's, it's shaders do most of the visual rendering part. Lights are shaders, shaders can create objects etc.

So they really just extend what you can do quite a lot. As for the MR shaders that come with Maya 6+, quite a lot of them you don't need to use (ie all the lamberts and blinns etc) because Maya already has those. Prior to Maya 6 the DGS material was useful because it offers blurry reflections, but now the standard Maya blinn and phong shaders do too.

It's really just about acheiving your rendered image. If you feel like things are fine without using any extra MR shader stuff, then that's fine! But if you suddenly find you need a shader that does X, or a light that uses real-world light profile info, etc, then there's a chance that a MR shaders can get you there.

Not to mention if you're a programmer you can just make them yourself!

02 February 2005, 09:15 AM
If you're bothered about physical accuracy then you should use mental ray's shaders. They tend to be a bit better about respecting the rule of conservation of energy than Maya's standard shaders and as a consequence your results will look better using, say, a dgs than a maya blinn.

02 February 2005, 07:55 PM
Hm, i see!
Im going trough all the data on your stickythread now jozvex and as you all said "..when you need more accuracy" etc etc
I gotta admit the reason i asked at first was because im starting to feel limited by the shaders in maya and want to start with more controll of the final rendered outcome!

Anyways, thanks for the reply and it looks like youre doing a GREAT job with that MR thread jozvex, way to go ;)

02 February 2005, 08:50 AM
Now, I nearly always render in mental ray for maya and I was wondering if someone please could help me point in a direction to where I can read up on what the advantages on using MR's very own shaders are?

Reading between the lines, I think what you really are asking is "why would I use something like mib_illum_blinn rather than maya's blinn"?

The answer is: The only reason is compatibility. The mib_* shaders is base shaders that come with all versions of mental ray for all platforms and all integrations, and will render on every mental ray under the sun.

If you use an application specific shader, such as a maya blinn, this will not render on a standalone mental ray unless you have the maya shader library installed.

But is the mib_illum_blinn somehow magically "better" than maya blinn? No.

But you could apply the exact same shader in Max or XSI and get the exact same result. This could have value for f/x-house to f/x-house "look compatibility".


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