Karma Renderer FAQs


What is the main difference between Karma and Mantra?

Mantra renders from Houdini using the ifd format and is not available as part of the Solaris LOP context.

Karma renders using the USD format and can only be utilized from within the Solaris LOP context.

Learn more here about the differences between the two render engines.

Is Karma ready for production use?

With H19, Karma CPU is production ready while the new engine Karma XPU is in alpha.

If you are using Solaris for lighting, you may want to consider using Karma XPU for interactive rendering in the viewport and Karma CPU for final rendering.

Learn more here about the differences between the two engines.

How does Karma CPU and XPU in H19 compare to Mantra?
Feature Mantra H19 Karma CPU H19 Karma XPU
Status Production-ready Production-ready Alpha
       
CPU Renderer Yes Yes Yes [Hybrid]
GPU Renderer No No Yes [Nvidia]
       
USD/Solaris Support No Yes Yes
IFD Support Yes No No
Open Image IO Yes | with Env Variable Yes Yes
       
Standard Surface Shader Principled - VEX Principled - VEX/USD Preview/MaterialX USD Preview/MaterialX
VEX shading Yes Some trace() function support No
       
CVEX: Lens Shader Yes Yes No
CVEX: Volume Procedurals Yes Planned for Future Release No
       
Toon Shader VEX Shading No No
Rounded edge/Dirt masks Yes Yes No
Texture Baking Yes Planned for Future Release No
Hair Shaders Yes Karma Hair
[can be used in MtlX networks]
Karma Hair
[can be used in MtlX networks]
Pyro Shaders Yes Pyro Shader[VEX] XPU Pyro Preview
[can be used in MtlX networks]
       
MaterialX Surface Shaders No Mtlx Standard Surface/USD Preview Mtlx Standard Surface/USD Preview
MaterialX Disney 2012/2015 No No No
Custom/Layered MaterialX Shaders No Yes Planned for Future Release
MaterialX SSS No Yes Planned for Future Release
MaterialX Color Management No Planned for Future Release Planned for Future Release
MaterialX Displacement No Yes Yes
       
Material Overrides Material Stylesheets [USD] | Assign Material and Material Variation LOPS [USD] | Assign Material and Material Variation LOPS
       
Adaptive Sampling Yes Yes No
Motion Blur Yes Yes Yes
Depth of Field Yes Yes Yes
Physical Sub Surface Scattering Yes Yes No
Random Walk Sub Surface Scattering No Yes No
Volumes Yes Yes Yes [Pyro Preview Shader]
Heightfields Yes Yes Yes
Instancing Yes Yes Yes
Nested Instancing  No Yes Yes
Deferred Geometry Load Yes Planned for Future Release Planned for Future Release
Subdivision HoudiniSubdiv/OpenSubdiv OpenSubdiv OpenSubdiv
Displacement Shading Yes Yes Yes
Crowd Support Yes Partial Support | USDSkel support, but not optimized Partial Support | USDSkel support, but not optimized
NURBS Yes Tesselated at Fixed Rate Tesselated at Fixed Rate
Lens Shaders Yes Custom VEX lens shaders No
Absorption and Nested Dialectrics Yes Planned for Future Release No
       
Denoising Optix Optix | Intel Optix | Intel
AOVs Yes Yes Yes
Deep Images Yes Yes No
Cryptomatte Yes Yes No
       
Light type: Point Point Light Yes Yes
Light type: Dome Environment Light Yes Yes
Portals on Dome Light Portal Light Yes Planned for Future Release
Light type: Distant Distant Light Yes Yes
Light type: Disk Area Light Yes Yes
Light type: Rectangle Area Light Yes Yes
Light type: Sphere Area Light Yes Yes
Light type: Cylinder Area Light Yes Planned for Future Release
Light type: Geometry Geometry/Volume Light Yes (points, curves, meshes, volumes) Planned for Future Release
       
Shaping Control: Cone Spot light Yes Planned for Future Release
Shaping Control: Focus Yes Yes Planned for Future Release
Shaping Control: Barn Doors Yes Yes Planned for Future Release
Shaping Control: IES Mapping Yes Yes Planned for Future Release
       
Light Linking Yes Yes [No Geometry Lights] No
Geometry Lights Yes Yes [points, curves, meshes, volumes] No
       
Render Curves Yes Yes [tubes, ribbons, oriented ribbons] Yes [tubes]
Render Points Yes Yes No
       
Viewport Render Yes Yes Yes
Render View Yes Render Gallery Render Gallerys
Interactive Mplay Yes Yes Yes [No click to render]
Render Snapshot Gallery Yes Yes Yes
Render to Disk Yes Yes Yes
HQueue - Distributed Rendering Yes Yes via Husk Yes via Husk
Standalone Command-line render Yes Yes via Husk Yes via Husk
CheckPointing Yes Yes via Husk No
     
VEX FUNCTIONS      
- gather loops Yes Simple Trace (no shading) No
- illuminance loops Yes Never will be supported No
- trace Yes Simple trace function (no shading) No
How much longer will Mantra be supported?

Development on Mantra is limited to critical bug fixes. The plan is for this level of support to continue until the end of 2024 (two years after Karma XPU is released) at which time Karma will take over as Houdini’s only supported built-in renderer. For as long as they are on AUP, customers will be able to keep their unsupported existing licenses until at least 2025.