How to Create and Assign a Redshift Material in Houdini Solaris

What you’ll learn in this guide

In this hands-on guide, you’ll learn how to create a Redshift material in Houdini Solaris and assign it to geometry in a USD scene. The workflow covers building a material network, defining the material’s path in the scene graph, and linking that path to geometry. It also explains why a new assignment may not appear and how to handle existing material assignments.

Solaris brings together USD-based scene building, look development, and Karma rendering tools in Houdini. Materials are therefore more than just shader networks: they also need a material path defined in the USD scene and a connection to the geometry that will use them.

Requirements

• You need a Houdini installation that supports working with Solaris/LOP networks. SideFX’s documentation has a separate section for Houdini 22.0, but it does not specify a particular Houdini version for the Redshift material steps described here.

• Redshift must be available in Houdini. The sources do not specify a particular Redshift version or license type.

• The sources list no specific hardware requirements for this workflow. They also do not mention an account requirement.

• Your scene needs geometry that can receive a material through Solaris. A USD material path must be defined for the material assignment.

Interface labels may vary depending on your Houdini or Redshift version. The steps below are based on the nodes and concepts documented in the sources; no unspecified versions or menu paths are assumed.

Step-by-step: create and assign a Redshift material

1. Prepare the Solaris scene workflow

You’ll create and manage materials in Solaris using LOP nodes. A Material Library LOP converts VOP shader nodes into USD materials and is one of the main ways to build a material network in Solaris. Make sure the scene’s geometry is also accessible in the Solaris scene graph.

2. Build a Redshift material inside a Material Library LOP

Use a Material Library LOP and add an RS USD Material Builder inside it. Build the Redshift shader network in the builder, then connect the shader output to the Surface input of the RS USD Material node. Maxon’s documentation states that the RS USD Material output works in Solaris and that the RS USD Material Builder is preconfigured for this output.

If you already have a Redshift shader network prepared in Houdini’s MAT context, you can copy it into the RS USD Material Builder and connect the relevant parameters to the Redshift USD Material output. This lets you bring existing shader work into Solaris, while ensuring the network is completed with a USD material output suitable for Solaris.

3. Define the material path

Before assigning a material to geometry, it needs a USD path in the Scene Graph Tree. The default settings in the Material Library LOP can automatically define paths for materials inside the builder using the * match in the Material VOP field. This path definition makes the material available in the scene graph for use in subsequent assignment steps.

Another option is to use Auto-Fill Materials. First, clear the default settings with the Clear button in the Material Library LOP, then click Auto-Fill Materials. The documented default placement puts materials under the materials path in the USD scene graph.

You can also set the material path manually for a more controlled network. Set the number of materials in the Material Library LOP, use the selection tool next to the Material VOP field to choose the relevant material, and repeat for any additional materials you need.

4. Assign the material to geometry

The Material Library LOP can assign materials to geometry as well as create them. Enable Assign to Geometry for the material and specify the target geometry in the Geometry Path field. In Maxon’s example, the geometry is selected by dragging it from the Scene Graph Tree into this field.

Alternatively, use a separate Assign Material LOP. Enter the material defined in the scene graph in the Material Path field, and the geometry to receive it in the Primitives field. To make multiple assignments through a single Assign Material LOP, increase the Number of Materials value.

5. Fix an assignment that isn’t visible

If the newly assigned material doesn’t appear, an existing material assignment on the geometry may be taking precedence. Two solutions are documented. If you’re using an Assign Material LOP, set the Strength value for the relevant Material Binding to Stronger than Descendants. This changes the priority of the new assignment relative to earlier assignments.

The other option is to remove the previous material binding with an Unassign Material LOP. Place this node after the relevant objects and before the Material Library LOP that applies the new material. Then check the assignment in your scene again. Using * in the Primitives field of the Unassign Material LOP removes material assignments from all objects upstream of the node, so carefully specify your targets when using it broadly.

Impact on architecture, interior design, and archviz workflows

This workflow is particularly useful for visualization teams assigning different Redshift materials to separate surfaces in an architectural scene. Clearly defining paths in the USD scene graph helps separate material creation from material assignment. For projects using more than one renderer, Maxon’s Collect VOP approach may also be worth considering: for example, a Principled Shader for Karma and a Redshift material can be connected to the same Collect VOP; Solaris selects the shader that matches the active renderer.

Before moving to a production scene, check that your Houdini and Redshift installations work together, that the material nodes you’re using are available in Solaris, and that assignments target the correct geometry. Since the sources provide no hardware recommendations, license costs, or specific version compatibility details, these should be verified against your project setup rather than assumed.

Common mistakes

• Assigning a material before defining its path: The path used by the Assign Material LOP must first be defined in the Scene Graph Tree.

• Using the wrong material output: The standard RS Material output is not compatible with Solaris; use the RS USD Material output for Solaris.

• Overlooking the Material flag setting: By default, the Material Library LOP may define paths only for VOPs with the Material flag enabled. Check this setting if a material isn’t added automatically.

• Ignoring an older material that overrides the new assignment: If the assignment isn’t visible, check the Strength value or consider using an Unassign Material LOP.

Next steps

Start by checking the connections in a small Solaris scene with a single piece of geometry and one material. Then, if your scene uses multiple renderers, try the Collect VOP approach and check how different shaders are managed within the same material selection. For more advanced work, consult SideFX’s Solaris documentation on LOP workflows, USD fundamentals, and performance tips. Before changing material assignments, identify which objects will be affected—this is especially important when removing assignments broadly.

Sources and licensing

This guide is based on SideFX’s Solaris and Houdini documentation and Maxon’s guide to materials in Houdini Solaris. The source records list the license status as “free”; since the pages do not specify an open-source license type, their content has been adapted into practical steps without copying source sentences.