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Add Materials
Let's spruce this sphere up a little bit. All of the new Pixar Surface Materials are available in RfK in the shader lists of the Material node and the PrmanShadingNode. For this simple scene let's just create a single Material node then select AddShader->bxdf:
Choose PxrSurface from the list of prmanBxdfShaders:
In order to connect the Material with its geometry you create and connect a MaterialAssign node and set the materialAssign attribute to the material location. The easiest way to do this is to Shift+middle-click and drag the Material node directly onto the MaterialAssign node:
If you enable the MaterialAssign node for editing (hover over the node and hit E) you could also Shift+middle-click from the Material node into the materialAssign box in the Parameter tab. Add the primitive to the Material CEL location in a similar manner to finish the material assignment:
Rendering at this point will still give you a diffuse grey sphere, so let's shine up our surface a little bit by adjusting Color, Fresnel and Roughness on the Primary Specular. Thus we have Sunrise on a Sphere:
Patterns
Attributes of PxrSurface can be connected to outputs from RenderMan's extensive set of pattern nodes. Things like texture, bump mapping and procedural color can be added by setting up a PxrSurface bxdf using the PrmanShadingNode instead of a Material node, then wiring that node into a NetworkMaterial node. This is the start of a shading network which you can extend as far as your creativity takes you.
Let's add a ground plane to our scene with some fractal-based shading. Use another PrimitiveCreate to add a plane. Then create a NetworkMaterial node and choose bxdf from the Add Terminal menu. Create a PrmanShadingNode and set the NodeType to PxrSurface. Add a new MaterialAssign node and connect the plane to the NetworkMaterial the same way you assigned the sphere its material. With a little rearranging and color coordination the node graph is now set up with a light, a camera and two pieces of geometry, each assigned a PxrSurface material:
The addition of our fractal shading is done with series of PrmanShadingNodes, each with a Pattern that feeds an output into the next with the last feeding its result into Color input of the PxrSurface node:
The above node graph uses the PxrFractal, PxrToFloat3 and PxrHSL patterns to convert fractal noise into a surface shader for our ground plane. Sunrise on a Sphere in a Fractal Sea:
Fine Tuning
Now that you have a renderable scene you can start fine tuning the render with adjustments to the shaders and to the renderer itself. Most adjustments to the shaders can be done during Live Rendering. Render configuration, on the other hand, must be set before the render starts (e.g. resolution, samples, integrator). RfK has several places for configuring renderer attributes. The most commonly-used settings are discussed below; more detail on these and the rest of the settings can be found in the Render Settings page.
General Render Settings
If RenderMan is the only renderer installed for your Katana session then it will be used by default when you render. If there are other renderers installed then you'll need to create a RenderSettings node and set the Renderer attribute to "prman":
The RenderSettings node is also where you control things like:
- image resolution
- camera
- crop window
- shutter open/close.
RenderMan Controls
RenderMan-specific rendering controls such as Options and Attributes are available in the PrmanGlobalStatements node. Other RfK configuration options are exposed here as well. For example, if you'd like your renders to go to the RenderMan Image Tool ('it') instead of the Monitor window you can control that with the renderDisplay attribute in PrmanGlobalStatements.
Next Steps
Now that you're familiar with all the basics, take a look at the Tutorials for more advanced shading and rendering workflows. If you're looking to improve either speed or quality of rendering a good place to start would be the Sampling Modes documentation.
Happy Rendering!
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