arnold6 USD tests

I am testing new Arnold6 native USD support. Fist time to pixel is super fast, 2-3 seconds on arnold6 CPU with 1 million splines USD asset 8 sec. on Arnold6 GPU in Houdini and Gaffer.

Its a shame, that’s Autodesk HtoA plugin is is unusable. interactive rendering does not takes any updates, except shader values changes and light exposure changes. Also, Arnold6 GPU have big render artifacts with spline render mode set to “Thick”. what it look likes a cool shader, are actually render artefacts.

also arnold6 GPU renders 5 times slower then CPU version as soon i turn on SSS or transmission. ( quadro RTX5000 vs Xeon 6 core at 2.4 GHz )

Gaffer make over

i am starting to use Image Engine Gaffer (opensource software) for some private projects. but vanilla version of the software is quite naked and not very user friendly, so i decided to pimp the software with my own extensions.

first step, pimp the node icon’s and make it 4k screen ready.

testing new Arnold 6.0.3 GPU renderer update on particles

Recent HtoA 5.2.1 made it possible to actually use Arnold6 GPU in Houdini, i tool it on a test ride with particles. (5 million particles).

the setup is quite simple, pure diffuse shading only AA samples. I’ve chosen a darker frame to test the sample quality.

CPU 2 minutes on 6 core Xeon

GPU 1 minute (Nvidia Quadro RTX5000), same sample count the CPU render above but more little more noise.

GPU 1:30 minute, increased the sample to get a noise free render.

the Arnold GPU render it getting slowly faster the Arnold CPU in some cases, there is still long road ahead to for the GPU renderer speed to catch up with competition.

star simulation with OpenCL

birth of a massive star. for my little #astrophysics exploration, i’ve created a star simulation using openCL in houdini. its based on nbody #physics model, only driven by #gravity. using #nvidia #quadro rtx 5000 #NVIDIAStudio. #arnoldrender

the colours are not quite right, I am trying to integrate kelvin colour temperature.  the current colour is based on density and speed.  

In this simulation, I assumed  48% amount of negative gravity to fill the mystery of dark matter. I used 1 million nbodies for the simulation.  for the steps, I am planning to add finer particle streams to get more details.

Renderman Spline rendering

I’ve tested RenderMan with spline rendering. it’s much faster compared with baked Geometry. the spline primitives are very good in Renderman.

I’ve stopped the test with mantra after 10 minutes, it is super slow even with optimized render settings.

the Renderman images rendered for 3:20 on a 6 core Xeon
2.7ghz with pxr pathtracer. 4k resolution


splines primitives:

rendering splines directly saves a lot disk space and meshing time. interactive rendering was super responsive.

Octane 2019.2 renderings is very fast, I’ve used the geo to render it. 2 minutes, as except its lot faster the CPU renderings. the spline rendering in octane does features custom width yet.

Octane gives physical correct shading out of the box. Renderman the shading is extreme flexible with NPR renderings, which is hard to get in Octane. the IPR responsibility was a little slow with shader tweaks.

atmossphere volume in arnold

rendered with Arnold in Houdini. I’ve tried the atmosphere volumes the first time. easy to setup. The render time was quite slow on the volumes, typically for volumes, but much faster then render the screen envr with VDB cloud. I’ve used a mesh light for inner character illumination. 

it’s a shame I could not use Arnold 6 GPU, because its missing features. Volumes would boost get huge speed boost with volume raymarching on a GPU. I had to use a denoiser from Affinity Photo in dark areas.

with Arnold 6 GPU it does not drop any errors, you have to wait 1-2 minutes if data is loaded to GPU and starts the rendering or not. even a wrong file pass to an Hdri image makes Arnold GPU drop out, you sitting and wait in front of a black screen and don’t know if it will render or not.

light simulation

I’ve made a simple scene to test the physics of light. for proper light calculation, I used spectral render Indigo and Octane.

Indigo has multiple Engines, standard Spectral Path tracer on CPU or GPU and Bidirectional path tracing with MTL sampling (metropolis Light Transport). Octane has only default Spectral Path tracer on GPU but includes an MTL sampling method. I’v also added Renderman 23 to the test with its unified rendering integrator. It supports bidirectional path, manifold caustics and path guiding on the CPU.  

Another render engine like Arnold or Cycles with regular Path tracing would impractical fro complex light calculation tasks.

The base scene is Sphere and squashed Sphere underneath inside a volume box (uniform VDB).      

The following image is the result of Indigo Renderer with BiDirectional path tracing and MTL. It was by far the fastest rendering.