Aleksandr Kirichenko

While working with MetaHumans in Solaris, I realized I needed a node to blend normal maps with micro-normal details. So I created a few simple nodes to handle normal maps in MaterialX.

Mtlx Combine Normals
https://www.orbolt.com/asset/FaitelsTech::mtlx_combine_normals::1.0
Combines two normal maps into one using a whiteout-style blend algorithm.



MtlX Flip Normals
https://www.orbolt.com/asset/FaitelsTech::mtlx_flip_normals::1.0
Converts normal maps between DirectX and OpenGL conventions by flipping the green (Y) channel.



MtlX Normals Intensity
https://www.orbolt.com/asset/FaitelsTech::mtlx_normals_intensity::1.0
Adjusts the strength of a normal map by scaling the X/Y components.



MtlX Rotate Normals
https://www.orbolt.com/asset/FaitelsTech::mtlx_rotate_normals::1.0
Performs an axis-angle rotation of the sampled normal vectors (not the texture pattern).
Rotates a normal map's vectors around the tangent Z axis.



The attached zip file contains Indie HDAs; a full commercial license will be available after review on Orbolt.

Great idea! One potential consideration is the ability to bake modifiers on geometry and shaders into textures. For example, cars often have subd modifiers, and plants have adjustable leaf shaders; therefore, all of this has to be baked beforehand.

Now that Metahuman licensing allows rendering in any DCC, the once strictly Houdini-to-Unreal character pipeline could become bidirectional. Does anyone know if SideFX or SideFX Labs is working on an Unreal-to-Houdini Metahuman workflow?

In my latest project, I rendered most of the scene with Karma XPU, then switched to Karma CPU when ultimate quality mattered or speed wasn’t a priority. A similar hybrid approach could apply here: render some sequences entirely in Unreal, then refine others with heavy VFX, such as FLIP or pyro, in Houdini with Karma.

Also, I’ve noticed that the Metahuman Grooming HDA is tailored to Unreal’s groom system, yet Unreal still doesn’t offer a native way to export groom strands to other DCCs without a paid third-party plugin.
By other side, it seems that Unreal has made huge leaps in many shot-related areas like custom aovs, OCIO, overall rendering consistency, USD support and fluids support, since its initial release, and holds a strong position in areas where Houdini is less present, including previs, virtual production, geometry-heavy environments, sound, live performances and character building.
Of course USD is key to tying all software together, but it still feels that bringing high-quality characters into Houdini will require close collaboration between dev teams (for example interchanging transparent materials is still great pain, and character not only have transparent eyes, but also sss skin and hair shaders).
Any insights would be greatly appreciated.