Mental Ray – skin shading

Posted on Posted in art

Using mia_material together with misss_fast_skin shader.

Better skin with the mia_material
By combining the blurry reflections and built-in ambient occlusion of the mia_material with the layered subsurface scattering of the misss_fast_skin shader you can get great looking skin while maintaining artistic control.

If you want to archive this, begin by setting the specular weight of your misss_fast_skin-node to 0. Also set your diffuse weight on your mia_material to 0. Then connect your misss_fast_skin-node to the Additional Color-input on your mia_material. This way you have all your diffuse component coming from the misss_fast_skin-node and all of the specular component of the mia_material.

What you then want to do is to connect the misss_fast_lmap to the Light Map Shader slot of the mia_material’s Shading Group. Simply drag and drop the misss_fast_lmap into the slot (with the middle mouse button). Your shading network should look like below.

Using mia_material together with misss_fast_skin shader.

example: Connecting the lightmap-shader to the mia_material’s Shading Group.

Don’t forget you still have to feed a writable 32bit mentalrayTexture to the misss_fast_lmap and connect that texture to the lightmap input on the misss_fast_skin-node.

Using normal and bump maps with the mia_material
Sadly, in maya 8.5, assigning a bump map to the mia_material can be quite troublesome, the documentation suggests a lenghty arrangement of nodes that I at first could make no sense of.

However I found a quick (and dirty) solution which involves borrowing the misss_set_normal-node from the misss-shaders. Just connect a misss_set_normal-node to the bump-slot of the mia_material and then connect a bump2d-node to the normal-input on the misss_set_normal-node. This way you can easily connect a file texture to your bump2d-node. A greyscale bump-map or even a tangentspace normal map will both work fine this way.

Connect normal map to mia_material

example: normal-map connected to mia_material through bump2d and misss_set_normal node.

In later articles I will discuss:

Making more use of the mia_material
Getting into the nitty gritty of metal IOR’s, colored reflections and reflection curves. And much more

Using the mr physical sun & sky
How to light your scene with a full dynamic range and render to an High Dynamic Range (HDR) Image and how to avoid common problems, such as using textures with a low dynamic range in your scene.

8 thoughts on “Mental Ray – skin shading

  1. Hi

    Iยดm having problems ๐Ÿ™
    will I still be using the sss shader and apply it on the model ? and where will I put my specmaps, reflectivity maps etc? at the moment it looks like a plane lambert when rendering.

  2. Hey Sven ๐Ÿ™‚

    The shader you should apply to your model would be the mia_material. Don’t forget to make sure your misss_fast_lmap is connected to the “Light Map Shader” slot of the that materials Shading Group.

    The mia_material doesn’t have a slot for “specular” as opposed to reflectivity, so you would simply connect your specular texture to the Reflection Color of the mia_material.

    You could then connect another (gray-scale) texture to Reflection Gloss, to control how shiny/glossy the reflections are across a surface (where 0 is totally matte, 1 is shiny like a mirror).

    Hope this helps! ๐Ÿ™‚

  3. Thanks for the reply ๐Ÿ™‚ I finally got it to work:)
    The grecscale texture that you mentioned is also supposed to be connected to the mia_materials Ref gloss, right?

    And another question. I would like to work with some tilable skin textures, bumpmap or normal map. I would like to have the tilable texture effect the spec bump and reflectivity. any suggestions on how to make this possible ๐Ÿ™‚

    I would be more than gald to send you some example textures and meshes to let you know what Iยดm working on ๐Ÿ™‚

    have a nice summer !!!:)

  4. Any workflow tips for setup of render passes for compositing such as the correct way to setup render passes in maya so that you can get output of specular, reflection, and color ?

  5. Hi I’m having a problem when connecting the misss_set_normal in the bump, the connection editor pops up :S Im using the middle mouse button.

    I’m using Maya 2010, and using this on the mia_material_x because the mia_material doesnt have a bump option.

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