Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: mediopolis on 2014-03-13, 05:21:18
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Hi fellow testers!
I have been playing around with corona for the last few days and I am stumped. My current machine specs are
dual x5650 @ 4GHZ
24GB Ram
amd firepro
When i render a scene similar to some of the test scenes i see on the home page. I see their render times of 20-30 minutes and they are virtually noise free, using CPU's slower than mine. But my are still full of noise and take about 2 hours or more to achieve the same level of noise reduction. Do these guys have special stuff going on in the background I don't know about? I am loving Corona so far though. Thx for any insight.
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I must admit (maybe i'm wrong) that A2 and A3 were faster but a lot buggy than the recent dailies, for example the red sofa render in corona home took me this time without using noise reduction tool and it was rendered with the A3 i think, i reopened with the new dailies and i see the floor reflection got noise a lot more than before if i remember and having the same rendertime it still got some noise on it... I repeat maybe i'm wrong but this is what i see comparing to the speed of the A3 and A2.
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ok thanks! Thought i may be going crazy for a minute there ;)
You would be right... I downloaded and ran the alpha4 test scene and it completed in 2:37 @ 100 passes with very low noise. Way faster than v5 alpha
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In Corona, as in any other renderer, it is essential to stick to certain rules if you want to keep everything smooth and fast. So when you are writing "a scene similar to some of the test scenes I see on the home page", I suspect that what really should be written is "a scene visually similar to some of the test scenes but prepared in a different way". Be sure to read this:
http://corona-renderer.com/wiki/performance_debugging
If you are doing everything correct, then it would be nice to see your render settings, materials and wires.
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Here is my scene with settings.. I let it render for about 20 minutes.
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1. You are rendering with path tracing as both primary and secondary solver. Changing secondary solver to HD cache should give you significant boost.
2. Looks like you have some huge lights in window holes. Why?
3. You should ALWAYS use portals in your window holes.
4. How is your background made? If it's a huge sphere with self-illuminating material applied, then it's wrong.
5. Always pay attention to realistic albedo (not too bright diffuse component) and reflectivity.
But switching to pt+hd should be your answer. :)
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actually i did render originally with HD as 2nd solver. had the same results.. I am going to tweak this and do another test.
This was a converted vray scene and i didnt adjust anything really. converted and hit render.... stay tuned for an updated test. thx!
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I must admit (maybe i'm wrong) that A2 and A3 were faster but a lot buggy than the recent dailies, for example the red sofa render in corona home took me this time without using noise reduction tool and it was rendered with the A3 i think, i reopened with the new dailies and i see the floor reflection got noise a lot more than before if i remember and having the same rendertime it still got some noise on it... I repeat maybe i'm wrong but this is what i see comparing to the speed of the A3 and A2.
Yes, corona lost a lot of "brute force power" in the last few versions. This was necessary to facilitate the advanced fake/shading/scaling/... algorithms. As a result, some scenes might render slower, maybe by a factor of up to 50%. But this was necessary to
1) implement algorithms that allow rendering of scenes that could not be done at all before
2) to be able to render fast some scenes that tool extremely long time before. In other words, even though generally it is a little bit slower, there are many scenes where new version is 10 times faster - motion blur, lots of lights, ...
Anyways, I will improve the speed in the future versions by implementing some smart stuff like progressivity and even better light sampling ;)
Here is my scene with settings.. I let it render for about 20 minutes.
To optimize:
1) use secondary GI solver HD cache, always for interiors
2) do not use any artificial lighting rigs. Only environment light and scene emitters like lamps, but not invisible lights in windows
3) add portals for an extra boost
3. You should ALWAYS use portals in your window holes.
Nope, they still remain optional. There are even situations where they will slow down the rendering a bit (huge windows, very dynamic HDRI)
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Keymaster... I am working on updating the scene and will post result.
thx, Josh.
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3. You should ALWAYS use portals in your window holes.
Nope, they still remain optional. There are even situations where they will slow down the rendering a bit (huge windows, very dynamic HDRI)
Thats explains a lot. I rendered car interior recently and was wondering, why portals in car windows, added quite significant slowdown. Now, i know why :]
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Yes, corona lost a lot of "brute force power" in the last few versions. This was necessary to facilitate the advanced fake/shading/scaling/... algorithms. As a result, some scenes might render slower, maybe by a factor of up to 50%. But this was necessary to
1) implement algorithms that allow rendering of scenes that could not be done at all before
2) to be able to render fast some scenes that tool extremely long time before. In other words, even though generally it is a little bit slower, there are many scenes where new version is 10 times faster - motion blur, lots of lights, ...
Anyways, I will improve the speed in the future versions by implementing some smart stuff like progressivity and even better light sampling ;)
You're right i prefer a little bit slower build but more stability and features like with the recent dailies so for me it's not a problem i'm enjoying it so far and it's just an alpha build so i'm so excited for the beta ones and the final, amazing job guys and for me Corona renderer is the future for sure no doubt !
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I also think (hope) I wont have to add significantly more overhead in the future.
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quick update...
This is only 1 hdri map in the environment. No other lights
20 min.
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Why are you using a Vray HDRI map for the environment?
Shouldn't it be a standard bitmap?
Cheers.
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I thought I read somewhere corona supports vrayhdri, so you can tweak the multiplier, gamma and other settings...
On a side note.. Is Shutter Speed, F-Stop usable for exposure control in corona?
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I see you have glass panes in windows, can you show material that's assigned to it?
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here is the glass material.
I am also testing some other scenes from mental ray (our primary renderer)
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Why are you using a Vray HDRI map for the environment?
Shouldn't it be a standard bitmap?
Cheers.
Why he shouldn't use vray hdri map ?
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Use simple bitmap, adjust white point and black point in HDRI or EXR depends on what you use for map to adjust gamma.
Exposure compensation works same as on DSLR camera, Highlight compression works same as Clamp output(avoiding over burning white points), both should be higher in your case, almost washed out.
Use Lights multiplier samples on default 2.0
Try using 32 PTS with default maximum sample intensity 20.
Absorption on your glass is way too high, try using double sided for refraction mode.
Try using default values first. Avoid using additional lighting in scene, except for Spots, lamps etc.
Try hiding glass on your windows and default values just to see how it goes, troubleshooting scene to see if there is something you should not have inside.
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Removed all the glass and the bookshelf.. 37min rendertime.
Update... i updated the attachments with a render with the Glass @ 37min
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What's your result with the Corona Benchmark?
Just out of curiosity to have a comparison time, I want to do a similar test and check your speed becasue I think it's a bit slow and I have a different feeling here, I'm not working yet with such complex scenes but my simple interior scenes are fast, so I'm a bit confused with what I see :)
Cheers.
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a4 scene attached. 2:44 was the time.
I agree. My scene is not that complex, so it's puzzling me also :)
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Your render times in your scene are very weird IMHO, specially after seeing your benchmark results :P
Try to see what happens if you remove all teh textures, leave the materials intact except for the textures, remove them, and remove also the HDR and any light source and start the lighting from scratch.
Also another test could be to put an override material with a simple grey, and try to render it.
About the vRay HDRI, the thing is that that is a Vray map, so maybe it's doing something weird for corona under the hood, so use a standard bitmap (just my opinion, I'm not sure this is interferring at all)
But it's obvious that there is something weird in your scene :P
If you can share your scene (or better, a reduced version of it that suffers the same problem) we can try it, I think you'r scene is rendering too slow for your system.
Cheers,
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About the vRay HDRI, the thing is that that is a Vray map, so maybe it's doing something weird for corona under the hood, so use a standard bitmap (just my opinion, I'm not sure this is interferring at all)
This is definitely not it, so far it's been completely sound to use VrayHDRi bitmap loader, which is vastly superior to default MaxBitmap not only through its controls (360degree, various gamma alteration modes,etc..) but also with its re-sampling methods (bilinear,etc.. compared to pyramidal,summed...), although the latter, might not be beneficial in Corona.
In all my works with Corona I used only VrayHDRi. Since I use very hi-res maps (up to 24 000px) I use the resolution multiplier next to light samples even down to 0.1 and lower. I am not sure if this "sIBL" sort of thing provides better noise convergence, I never tested, but I neither experienced any problems at all.
Highlight compression works same as Clamp output(avoiding over burning white points)
It works as tone-mapping, compressing the highlights. Clamp affects dynamic range of the ouput. Two absolutely different things.
Regarding light portals, I also use them very rarely. They help greatly with noise, but only in certain conditions where the interior space has very limited access to environment.
Definitely not a must.
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Rendering with a standard override mat was fast! So, I plan to add them one by one, to pinpoint which was causing the issue.
This render was 3:30
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[/quote]
It works as tone-mapping, compressing the highlights. Clamp affects dynamic range of the ouput. Two absolutely different things.
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You are right! Cheers ;)
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This is more in line with what I could expect from your computer :)
Tell us here what material was the problem when you reach to it please.
Cheers.
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It was the blend materials (wood and wall materials), were the culprits. Just like the performance debugging page said for slow times. It is pretty amazing how drastic blends slow down corona. Easily by 50% or more when i added blend materials.. Even adding just my bookshelf wood texture added a good bit of time, leaving all other materials with a standard corona material.... lesson learned! ;) I wish there was a mental ray & maxwell material converter, which is what all our high-end scenes are done in usually.
Can't wait for distributed render so I can see how my render farm of 100 cores would do!
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I wish there was a mental ray & maxwell material converter, which is what all our high-end scenes are done in usually.
There is one capable of converting Arch&Design mats but not maxwell materials http://forum.corona-renderer.com/index.php/topic,126.0.html (http://forum.corona-renderer.com/index.php/topic,126.0.html)
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most excellent. Didn't realize this same one did mental ray mats also. Thanks Deadclown :)
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I'm also open for maxwell license donations to provide maxwell conversion support :D
Just kidding, but as far as I remember maxwell materials are kind of different to the average max materials with own maps and stuff, so I guess this won't happen.
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alpha6 is fast! Man, I am loving it now using my render farm.. I think this is one of the fastest distributed renders i have used now!