How to use A23D PBR Textures in Houdini

This guide explains how to import and apply A23D PBR texture maps in Houdini using either the Principled Shader (Mantra and Karma CPU) or MaterialX (Karma CPU and XPU).

1. Download and Extract the Texture Set

  1. Sign in to your A23D account.
  2. Browse to the texture asset you wish to use.
  3. In the Software dropdown on the asset page, select Houdini. A23D automatically delivers the PBR texture set in the format best suited to Houdini (JPG maps) - no manual format selection required.
  4. Click Download, save the .zip, and extract it. You'll find:
    • A23DTEX_Albedo.jpg - Base color
    • A23DTEX_Normal.jpg - Tangent-space normal map
    • A23DTEX_Roughness.jpg - Surface roughness
    • A23DTEX_Metalness.jpg - Metallic values
    • A23DTEX_AmbientOcclusion.jpg - Ambient occlusion
    • A23DTEX_Height.jpg - Height / displacement
    • A23DTEX_Opacity.jpg - Opacity (where applicable)

2. Create a Material

Option A - Principled Shader (Mantra / Karma CPU)

  1. Open the Material Palette or dive into a /mat network.
  2. Drag a Principled Shader into the network.
  3. Double-click the node to open its parameters.

Option B - MaterialX Standard Surface (Karma CPU and XPU)

  1. In a Solaris (LOP) /materials library, create a MaterialX Builder subnet.
  2. Inside, add a MtlX Standard Surface and a MtlX PBR Texture Set VOP. The PBR Texture Set node organizes all PBR maps in one place and connects directly to the Standard Surface inputs.

Why MaterialX? SideFX recommends MaterialX as the future of shading in Houdini. Karma XPU (GPU) only supports MaterialX shaders, while Karma CPU supports both Principled Shader and MaterialX.

3. Load A23D Texture Maps

In the chosen shader, load each A23D map into the matching slot:


Houdini Shader ParameterA23D Map to UseNotes
Base Color / AlbedoA23DTEX_Albedo.jpgLoad into the Base Color slot. Set Color Space to sRGB.
Ambient OcclusionA23DTEX_AmbientOcclusion.jpgMultiply with Base Color in the shader network for added contact shadow.
Normal MapA23DTEX_Normal.jpgWire through a Normal Map VOP (Tangent Space). Set Color Space to Raw / Linear.
RoughnessA23DTEX_Roughness.jpgPlug into Roughness. Color Space = Raw.
MetallicA23DTEX_Metalness.jpgPlug into Metallic. Color Space = Raw.
Height / DisplacementA23DTEX_Height.jpgConnect to Displacement input on the shader, or Material Output Displacement in Solaris.
OpacityA23DTEX_Opacity.jpgWire to Opacity. Color Space = Raw.

4. Apply the Material to Your Geometry

At the Object level (Mantra / Karma CPU)

  1. Select your object.
  2. In its Render tab, set the Material parameter to your new shader.

In Solaris (USD) for Karma

  1. Add an Assign Material LOP, point its primitives to the geometry path, and set the material to your MaterialX shader.

5. Preview and Render

  1. Enable Material Shaders in the viewport to preview the applied textures.
  2. For displacement:
    • Enable Subdivision and Displacement in the object's render properties, or set displacement bound in the MaterialX shader.
    • Increase mesh subdivision quality where the silhouette must follow the height.
  3. Render with Karma, Mantra, or Redshift.

Additional Tips

  • Use the MtlX PBR Texture Set VOP in MaterialX to keep all maps organized in one node.
  • For Redshift, an RS Standard Material accepts the same A23D maps - base color, roughness, metalness, normal, displacement, opacity.
  • Adjust UVs in SOPs if textures look distorted on the model.

Additional Resources

For more shader network details, refer to SideFX's official documentation:
Principled Shader - Houdini Help
Karma User Guide - Materials
Using MaterialX in Solaris

Need some help?

Contact our team at support@a23d.co