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Rendering with Arnold in Houdini and Solaris using the HtoA plug-in.
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HtoA - Renderview and render time low performance

Message 1 of 7
1409 Views, 6 Replies

HtoA - Renderview and render time low performance


I have a question about Arnold's performance between C4D and Houdini. Here the same scene with same setup + setting and C4D run so much faster than Houdini ( around 17 ~ 19 seconds ).

I'm using Houdini 18.0.416 with HtoA 5.2.1 and Cinema4D R21 with C4DtoA 3.0.3 running on macOS 10.15.4 ( Catalina ) on Macbook Pro 16.



The problem is C4D only takes 1~2s to generate the scene and Houdini takes at least 10s.

One more thing, in C4D when I change any parameter, Arnold updates instantly. But in Houdini, it only changes when I move lights or object around. If I drop down some shader node like Curvature or AO and plug it to the OUTPUT, I have to re-render to renderview and it takes too much time to generate the scene even the simplest one.

Is there any solution to speed up in Houdini ? I'm switching to Houdini to do all of my work now and it's really annoying to be slowed down while doing the lookdev.


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Message 2 of 7
in reply to: voklmun

nope, hotA in general is super buggy, laggy and missing most of important IPR Arnold features.

Message 3 of 7
in reply to: voklmun

I'm using Maya 2023.1 and Houdini 19.0.657, both with Arnold (H6.1.2.3 and M5.1.3.2), in Maya with IPR the render update starts after 2 seconds with a new refresh, where Houdini takes 27 seconds before the render begins, this is with GPU, but when I use the CPU rendering with Houdini the lag is reduced to 15 seconds or so. I have tried everything possible to look for the reason but after loosing so much time I'm about ready to give up, I use Houdini but for look dev it just doesn't cut it, the time it takes to refresh a IPR is ridiculous, if I use the Arnold render delegate in Solaris there is no lag and the render start immediately, just as it does in Maya, so what the hell is going on?

Any help on this front would be a god send...

Message 4 of 7
in reply to: voklmun

if use USD precodural  it should faster startp time ?  i guess wi the sop houdini geo it convert it arnold support format before it start to render

Message 5 of 7
in reply to: voklmun

I finally figured it out after a week of analysis, I created a template material which had an Ambient Occlusion node in it, the AO node went through a switch which was disabled in the material by default, so I didn't think this would cause a problem, but it did, when I built a scene with many objects in it and 30 materials on these objects it took almost 30 seconds before the render started, the CPU render started immediately, but the GPU render took the time to prepare the materials and feed them into the GPU memory. I ended up creating another template material without the AO node in it and used that to recreate the other materials in the scene and BINGO.... the GPU render takes 2-3 seconds before commencing the render. Very strange that there is no info on this problem anywhere on the internet. Also, the Maya version still starts rendering faster than Houdini, but I suppose this is because the code in Maya is optimized where the code in Houdini is not, no problem, I am very happy now that this issue is sorted...

Message 6 of 7
in reply to: voklmun

I am also very interested in comments from the devs on this topic. I really enjoy rendering with Arnold for its stability, scalability and simplicity but working in lookdev with htoa is a task where you need a lot of patience.

_IF_ the renderview updates you can often be sure that it did not fully update _all_ the nodes that were changed, so it is often the better choice to restart the render. If you are dealing with a heavy scene this could mean a couple of minutes before rendering starts again.

Often times stopping a render is also taking a huge amount of time, so it is sometimes way faster to kill the hick process in the task manager and restart it again.


Will the export time, the supported nodes that are forcing a successful refresh of the render ever been addressed? There are a lot of tickets for the various topics for that, some of them a couple of years old.

I guess the big studios use their own exporters but there are many independent freelance artists or small studios that rely on a fast and reliable export to Arnold.


Thank you very much!


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Message 7 of 7
in reply to: cipy6L6MD

the best way for interactivity is Solaris, that whole point of USD anyway. by Sidefx is far from ready with Solaris. Houdini itself is rarely used for lighting/rendering. it's generally painful compared to other software packages unless you use Mantra.
by far the best Arnold "render" solution is GafferHQ. I am biased because I working with it for 6 years, but now its getting into a place, where you can use outside a pipeline. it has awesome interactivity, is workflow is closer to houdini (way better then solaris) and handle large scene very well.

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