I saw during the USD YouTube video premiere today that somebody from SideFX mentioned in chat that Karma speed improvements are coming. Very glad to hear it. I've had a chance to dial in Karma a bit more over the last few weeks and the resulting images are exceptionally high quality. It's just the speed thing is a real killer. It's faster than Mantra for sure (and Renderman too, mostly), but it's still lagging well behind pretty much everything else. Once that is addressed SideFX will have a real winner on their hands!

Hi Brian

That was me asking. Testing it in interiors, it is really slow. 20 hours verse 2 hours for Arnold. Currently using both denoising methods is producing smearing effects in the darker areas for Karma over multiple frames. For Beta it is not bad though. Renderman's speed is not bad although it is missing deep and crytomatte.

Rendering out lightGroups/multiLight in all the render engines requires LPE's right now. That is my other small annoyance. If you have a load of lights it takes forever to set up the AOV's per light.

I am sure SideFX will get to all these issues in time. They are far ahead of other apps.

Best Mark

Mark Wallman
I am sure SideFX will get to all these issues in time.

Yep, SideFX always makes it happen. Karma's got a ways to go right now, but I'm sure patience will pay off!

For a while I felt quite positive about Karma but the more I use it the less optimistic I'm about it's performance. It's slow, especially when scenes get complex and with lots of instanced geo. I find renderman, 3delight, arnold, and redshift just much speedier, by a lot. Promises of render speed improvements sound good but I fear that Karma is just fundamentally on the wrong foot in that respect. It feels a little old school tbh and there's just nothing really outstanding about it.

Now, I still stick to it. Why? Because the licensing, bug fixing, and general interoperability with Houdini, and price (!) of other renderers just annoys me too much. It's lovely to have a renderer that just works, doesn't require me to remember how I got it to install last time, doesn't break when I get the latest daily built, and if I come across a genuine bug sidefx will likely fix it that same week.

Soothsayer
doesn't require me to remember how I got it to install last time

Ha, I know what you mean! I agree, it does feel old school. I'm still optimistic they'll streamline it, but I'm a realist and I expect it will take a year or two at least.

Hi. Maybe because I have been using Arnold and 3Delight recently but in comparison there are a lot of controls and variables to the Karma render settings. One thing affects another and so on. It does feel like changing one small setting on one thing has a butterfly effect on other things.

Having said that I know Renderman like's its knobs and buttons as well.



Best

True, Karma is definitely in the Renderman tradition of a billion settings for everything. It's a bit much. I'd like to see SideFX dump the "advanced" Karma settings off into another tab. 3Delight is on the right track: shading samples, pixel samples, a few bounce settings and that's it.

Hi. The good thing about 3Delight and Arnold is after using them for a few days you can instinctively know what settings to use. I have been trying Karma for longer than 3delight but it is still not very apparent the best settings to use.

It took me nearly 4 full days to get the best settings for an interior render in Karma. It took me under 20 mins in 3delight. I could have rendered the whole thing out a few times over by the time I worked out Karma's best render settings.

I think it is going to be fixed soon but right now Karmas indirect samples also have an effect on the direct light alasing.

Like others I am being forgiving right now as I know it is still in Beta. But I really hope some of the controls and setting are simplified. Right now Karma feels like a science project. Fingers and toes crossed for the future. The future is simplicity!

Best

Mark

Mark Wallman
The future is simplicity!

Hear, hear!

I'm studying Karma a lot trying to get insight into what settings you truly need to worry about. It has so much potential. A modern renderer with USD support, tight Houdini integration, and fast renders would be incredible. Arnold and Maya are a great pair. Can Houdini and Karma surpass them?

Mark Wallman
It took me nearly 4 full days to get the best settings for an interior render in Karma.

I'm curious as which settings you found yourself tweaking? Is this a problem with bad defaults, documentation, settings names, or unexpected responses by Karma itself? I'd love to know (and I'm sure SideFX wouldn't mind knowing either) so anything you can share would be great

Hi Jason

I already gave SideFX my scenes for them to se as well. But in a nut shell. Most of my tests were done with the indirect Convergence mode set to variance. These are the settings that say indirect but also effect pixel samples. It would make sense the other way around but not indirect effecting pixel samples.

In all of my tests I ran diffuse limit at 15 but left all the other limits at default. For motion blur, good aliasing (this can be seen more apparently in the normal pass) etc you need quite high pixel samples, but this kills render times. I also played quite a lot with the noise level. One thing I was trying to speed up renders was to use the lightMixer LOP to over expose all lights. (you also have to go inside the Karma HDA to increase the light clamping limit for this to work). This made less noisy renders when the exposure was brought down again in Nuke. By doing this I could get to a cleaner image faster than reducing the noise Level in the Karma HDA.

I also tried indirect convergence mode set to distributed. for me this give the most predicable results but the render times went up to a small eternity so it is not practical to use.

I should point out in all my tests I am rendering, I am rendering the insides of buildings as I want to test indirect settings against other renderers. Currently I am only assigning a none specular 0.18 grey material.

Best Mark

Mark Wallman
(...) I also played quite a lot with the noise level (...)

Speaking of "Noise Level" (and I'm sorry for my possibly silly question), why is "Noise Level" not available in Karma XPU? Is it because it's impossible to implement Variance on XPU architecture for some technical reasons, or is it simply because the feature wasn't yet implemented in the Karma XPU's alpha stage yet?

ajz3d

Mark Wallman
(...) I also played quite a lot with the noise level (...)

Speaking of "Noise Level" (and I'm sorry for my possibly silly question), why is "Noise Level" not available in Karma XPU? Is it because it's impossible to implement Variance on XPU architecture for some technical reasons, or is it simply because the feature wasn't yet implemented in the Karma XPU's alpha stage yet?

I can only guess, but more likely the latter.

jsmack
I can only guess, but more likely the latter.

Thanks. Is there any info available about what additional features we might expect to be added to Karma XPU in the next Houdini release? I'm very thrilled about it and simply can't wait for the next major build.