Digital Tutors: Utilizing Shading Networks in Maya

Utilizing Shading Networks in Maya: This tutorial from Digital Tutors covered some of the topics we went through in class like layered textures and reflections but it was good for practice and also went into bump maps, displacement maps, transparency maps, layered shaders and volumetric shaders. I was thinking the volumetric shaders might come in particularly handy in our last scene where we’re looking up at the giant monument. I was thinking we might be able to give the monument a feeling of large scale by pushing the top of it back with volumetric scattering? This is my render from the tutorial:

volumetric_light_01

This is a bit ugly but if you google image ‘maya volumetric lighting’ there are some nice results. This adds a lot to the render time though, like the frame above took 3mins:13secs on my laptop and doesn’t even have a lot else going on in it.

These are my rough notes from the tutorial:

  • 2d textures are placed according to the UV layout. 3D texture doesn’t accurately show in viewport. Projection manipulator box controls display of 3D texture. Moving the object will make the 3D texture swim on surface.
  • ‘Assign as projection’ for material and align projection manipulator with camera view.
  • Texture reference objects: ‘create texture reference object’. Stops the texture projection from swimming when geometry is moved. Plug alpha image into specularity also so as to not have specular highlights on transparent region. If bump/displacement map is behind transparent alpha texture, may need to adjust transparency threshold of shader group.
  • A thick arrow indicates multiple connections to/from node. Colour is default output….can be changed e.g outColourR with output arrow or in connection editor.
  • Bump map: illusion of detail through light and dark information of texture.
  • Displacement map creates additional geometry at render time. From a .tga file. The displacement map connects at the shader group level. Create ‘displacment approximation’ (under rendering editor) will create resolution where it is needed.
  • Transparency maps inside shading networks: plug colour and alpha files into the colour and specular maps of blinn. Also adjust transparency in the shader group if a bump map is behind transparency map in render view.
  • Making reflections: adjust settings under ‘quality’ in render settings and attributes for material and lights.
  • Refractions: under raytrace options. glass has refractive index of 1.6. Also adjust max ray interactions in global render settings. Max trace depth = refractions + reflections.
  • Layered textures:  from left to right = top to bottom layers. Can also drop in files e.g. painted decals/patterns based on UVs.
  • Layered shaders: create layered shader and plug material onto the layer stacks.
  • Two-sided shading:  display face normals to check back/front. mental ray>sample compositing>twosided. Connect out value of twosided shader to outcolour of a ‘surface shader’.
  • Volumetric shaders: apply volume fog to a volume primitive (like a container). Plug a 3D texture into transparency to create some noise. Adjust inflection, frequency etc. In render settings adjust >features>volume samples to about 10. Adjust shadows within fog through light attributes ‘enable ray trace shadows’. Adjust ‘shadow rays’ and ‘ray depth limit’. Adjust fog settings to interact with light illumination.
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