Author Topic: long render times for noise reduction  (Read 12735 times)

2014-03-13, 05:21:18

mediopolis

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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.

2014-03-13, 15:10:08
Reply #1

Chakib

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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.
« Last Edit: 2014-03-13, 15:48:54 by Chakib »

2014-03-13, 15:36:01
Reply #2

mediopolis

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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
« Last Edit: 2014-03-13, 15:49:25 by mediopolis »

2014-03-13, 15:48:30
Reply #3

maru

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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.

2014-03-13, 16:52:17
Reply #4

mediopolis

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Here is my scene with settings.. I let it render for about 20 minutes.

2014-03-13, 18:19:39
Reply #5

maru

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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. :)

2014-03-13, 19:07:12
Reply #6

mediopolis

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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!

2014-03-13, 19:52:32
Reply #7

Ondra

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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)
Rendering is magic.
Private scene uploader | How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2014-03-13, 20:01:38
Reply #8

mediopolis

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Keymaster... I am working on updating the scene and will post result.
thx, Josh.

2014-03-13, 20:35:35
Reply #9

romullus

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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 :]
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2014-03-13, 21:58:35
Reply #10

Chakib

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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 !

2014-03-13, 22:18:02
Reply #11

Ondra

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I also think (hope) I wont have to add significantly more overhead in the future.
Rendering is magic.
Private scene uploader | How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2014-03-14, 00:37:40
Reply #12

mediopolis

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quick update...
This is only 1 hdri map in the environment. No other lights
20 min.

2014-03-14, 00:48:45
Reply #13

juang3d

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Why are you using a Vray HDRI map for the environment?

Shouldn't it be a standard bitmap?

Cheers.

2014-03-14, 00:52:32
Reply #14

mediopolis

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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?
« Last Edit: 2014-03-14, 01:01:23 by mediopolis »