Pixel peeping Houdini’s new Karma renderer

3D assets from Adam Swab

Now that Houdini’s new Karma renderer is out of Beta I wanted to see what it could do. Working through Adam Swab’s fantastic Houdini Solaris workshop gave me a chance to test it on a sample shot and I was impressed by Karma’s speed and quality. Working through Adam Swab’s fantastic Houdini Solaris workshop gave me a chance to test it on a sample shot and I was impressed by Karma’s speed and quality.

https://youtu.be/Tvj2XklNEX4?si=7HfZFij3BzMQdqWt

I wanted to see how Karma might compare to Arnold so I converted the materialX standard surface shaders to HtoA 6.2.5.0 and rendered with the same samples to see what the render times would be like.  Here are the results using Karma XPU, CPU and HtoA, rendered 1280 x 1280, on a AMD Ryzen 3970X (32 core) with a single NVIDIA RTX 3090.

Karma CPU

Karma XPU

Arnold 6.0

Karma CPU with Optix Denoiser

Karma XPU with Optix Denoiser

Karma CPU comes in at 1:16 a frame versus HtoA’s 1:36 and looks great.  Even better is that Karma’s XPU (GPU renderer) clocks in at blistering 0:38 and is virtually identical to the CPU renderer.    SideFx has made tremendous strides with the release of Houdini 20, Solaris and Karma.

Technical notes:

I’m lighting using OCIO ACEScg with a “ACES 1.0 SDR Video” view transform.  This comes standard now in Houdini 20.  The motion blur is vector based and gives a nice result. I love that the Karma’s Denoiser is a one click affair. I noticed that the specular IOR fresnel roll off was different between the material X shader and HtoA’s standard surface shader using similar settings.