Advantages of an all MR render

[Jozvex]

I've been thinking, and because MR in maya, renders maya shaders also, would there be a speed advantage of keeping a scene purley mental ray shaders rather than mix the two?

Well, yes and no, but mostly no I think. When you render using MR, regardless of what shaders your scene uses, Maya firstly has to convert the scene into the MI format. So basically you're always using MR shaders to render anyway. The only reason why it might be slightly slower to use Maya shaders is because there are a lot more attributes to calculate on say a Maya phong as compared to a MR phong. So I guess Maya shaders may be slightly slower.

but can you also include maya shaders in the bake?

Yep! The scene translation that happens at rendetime is the same as baking, only no .mi file is saved to disk.

I think....

:scream:

[butCherHeLL]

There is many mentalray shaders.Also many of them are spesific to their aims.

so they are more spesifically rather than a maya shader....

a maya shader has lots of parameters.this means there is more parameter types and values have to be converted to .mi (underground) when you press render.

more parameters means also more time to be calculation.

I prefer you to use mentalray's own shaders.instead of maya shaders.

but this also means you nedd more time to adjust all of them.

heh :thumbsup: good luck.

[cpan]

yeap i preffer mentalray shaders too (not the mib_phong, mib_lambert... ones but custom ones like ctrl_shading, mix8, etc)

oh, and if u need physical illuination, mray shaders is the only option :)

[BillSpradlin]

There are a lot of functions on the base Maya shaders which still get called during rendering even if they return null. So by building your shader networks as simple as possible (using the custom mental ray shaders as building blocks) the more efficient your render will be. Writing your own custom shaders as well that have single functions is also something that could be done if you really want to optimize things. You could cut down a tremendous amount of time this way.

[floze]

oh, and if u need physical illuination, mray shaders is the only option :)
No sir. You just need to know what's going on behind the curtain:

http://forums.cgsociety.org/showthread.php?t=228118

Same for photons. If you use the technique described in the thread above, simply turn off 'Derive From Maya' under the 'mental ray> Photon Attributes' tab of your shader, push the button to take the settings from maya and set the diffuse back to 1. This gives you results very similar to a dgs (not in terms of speed though).

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.