Houdini Engine for Unreal
 All Files Pages
Materials

Table of Contents

Materials can be assigned to generated meshes by either specifying an existing Unreal Material Asset By Attribute, or by allowing the plug-in to attempt to Generate generate a new Unreal material based on the Houdini material that is found.

By Attribute

The special Unreal to Houdini attribute unreal_material can be used to specify an Unreal material asset to apply to a given primitive.

This attribute should have the path to the asset as it's string value. The path to the material asset can be obtained by right-clicking on it and choosing Copy reference in the context menu.

Generate

Optionally, the plug-in can attempt to generate an Unreal material that matches a material applied in Houdini.

This is accomplished by reading parameter values on the associated SHOP or VOP nodes.

Textures will be generated by copying the associated data from possible channels which are connected through parameter names or tags. Likewise constant values for each channel will be detected.

Channel Parameter / Tag
Diffuse ogl_diff, basecolor
Opacity ogl_alpha
OpacityMask ogl_opacitymap
Normal ogl_normalmap, normalTexture
Specular ogl_specmap/ogl_spec, reflect_texture/reflect
Roughness ogl_roughmap/ogl_rough, rough_texture/rough
Metallic metallic_texture / metallic
Emissive ogl_emit, emitcolor

Note: ogl_normalmap_type will be read to determine the space of the normal map ( Tangent vs World )

Then an Unreal Material that connects Sampler nodes for those new texture assets into the Material results will be generated. This will trigger a recompilation of the associated shaders for the new Materials which may take some time.

Please note that textures are required to be cooked to a file. Textures created by Houdini Engine will be created in the cook temp folder (HoudiniEngine/Temp), do not forget to save them with your level.