kitchen shot

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Maximus
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Re: kitchen shot

Post by Maximus » 07 Mar 2012, 03:17

Ok here, let me try to explain what was my whole issue.

Basically i cant get a clean glossy effect when things gets reflected on that metal wall. I have no idea what is wrong and spent 2 days hiding/unhiding and rendering stuff. Still i never be able to fix this.

Here are the images:

Image

Image

Image

What has been tried:

- Glossy samples on all materials in the scene up to 256.
- All materials have Cutoff set to 0 in the optimization tab to avoid problems.
- Tried insanely hight unified/normal AA settings up to 1-3 rgb 0.01
- Tried to increase all lights samples up to 24
- Tried to relight the scene with just a point light
- Tried to recreate shaders
- Tried mia_material

Here is the scene, i kinda gave up.
There is something i'm doing wrong or it is just a bug. Clueless.

Thanks whoever can take a look and for help guys.

Max

http://www.2shared.com/file/MGDd5LhE/K_ ... share.html

Kzin
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Re: kitchen shot

Post by Kzin » 07 Mar 2012, 09:26

i will take a look on your scene on evening.

from you settings i think i know whats the problem, its not enough samples for glossis.
you have wide glossis and render them only with 2048 sample with adaptive aa, its simply to low. from my experience, you will need something like 0;3, treshold 0,05 and local samples set to 512 with distance change range optimization or perhaps with falloff from brute force to interpolation. i think this could work best here and it will renders alot faster then your current method.
also, unified will give you here alot of benefit because it renders the parts that needed it with much more samples and areas without alot of changes in shading with less samples.


for the lighting, the best way to get what you need is to shade in lambert mode with mia_mat (or arch_mat). you should always use this mat, its the mr version of the vray mat you always use in vray for example. it has some optimization regarding arealight sampling and in general optimizations for glossis. without to took a look on the scene, i am not sure if 16 samples are enough, portals has to bet set with enough samples, otherwise, you can get sampling problems without to know that the portals causes them.

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Maximus
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Re: kitchen shot

Post by Maximus » 07 Mar 2012, 10:00

Kzin wrote:i will take a look on your scene on evening.

from you settings i think i know whats the problem, its not enough samples for glossis.
you have wide glossis and render them only with 2048 sample with adaptive aa, its simply to low. from my experience, you will need something like 0;3, treshold 0,05 and local samples set to 512 with distance change range optimization or perhaps with falloff from brute force to interpolation. i think this could work best here and it will renders alot faster then your current method.
also, unified will give you here alot of benefit because it renders the parts that needed it with much more samples and areas without alot of changes in shading with less samples.


for the lighting, the best way to get what you need is to shade in lambert mode with mia_mat (or arch_mat). you should always use this mat, its the mr version of the vray mat you always use in vray for example. it has some optimization regarding arealight sampling and in general optimizations for glossis. without to took a look on the scene, i am not sure if 16 samples are enough, portals has to bet set with enough samples, otherwise, you can get sampling problems without to know that the portals causes them.
I'll wait for you to take a look at the scene but from what you've telling me that would take insane hours to render that scene.
My render in this thread was 8 hours and 40 minutes and i didnt have that high sampling.. Would it be 20 hours render for a so damn simple scene? I'm a bit speechelss :)
And i always use mia_mat for everything.

Thanks again for bein so helpful Kzin.

Max

Kzin
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Re: kitchen shot

Post by Kzin » 07 Mar 2012, 10:53

just to clarify this point, what is your system on which you render?
i have a z800 at work and only a quad 9450 at home, so i see some things different at work, rendertime wise. ;)

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Maximus
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Re: kitchen shot

Post by Maximus » 07 Mar 2012, 11:01

i have a 12core machine, intel i7 990xtreme clocked at 4ghz. 24g ram

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ActionArt
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Re: kitchen shot

Post by ActionArt » 07 Mar 2012, 15:30

The first thing I noticed was that your final gather settings seem to be reversed. Try swapping the rays and points setting. It should be more like 100-600 rays and 15 points or so.

One other thing. The maximum reflection bounces is too high. For glossy reflections like this I'd try 2 or 3 at the very most. If this is a still, you could use the reflection optimization in the Arch material to blur the reflections with a lot less samples. Try the default settings as a test.

Just testing now to see if that makes a difference...

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gustavoeb
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Re: kitchen shot

Post by gustavoeb » 07 Mar 2012, 15:58

Hey Max, I thought I would give this a try... This was my approach:

1. Open the scene
2. Turn off FG for iterating faster
3. Disconnect the Photographic Exposure lens shader (as it is buggy when working with local samples at 1)
4. Use the preview window instead of the render regions (as it is buggy when working with local samples at 1)
5. Bring all local samples in the scene down to 1
6. Bring max reflections down to 2
6. Render Unified min 0.5 max 10000 with quality at 1

Result: Incredibly fast and crappy reflections...

7. Render only selected objects
8. Select one object and try increasing the quality to 10

Result: 40 seconds just to render the objec "P00" but very good quality

9. Bring quality back to 1
10. Increase local samples until I am satisfied with the quality

Result: 6 seconds and very good quality for the same objet

11. Repeat this proceadings with all objects that were not doing well with local samples at 1
12. Render an EXR and apply CC that was being applied with P.Exposure in comp...

Results: Sampling looks good enough (not perfect, but you can keep increasing the sampling). 40 minutes (waaaaaay too long, but Im running a Core2Duo)

You can see the result attached.
While you may argue that the more reflections, the better it looks (and I agree), I think 2 is good enough for the look of this scene... Ive tried 1, but it really was too little.

Ill try rendering it souly with the quality parameter, but from my intuition that will take a lot longer, lets see...
Cheers!
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gustavoeb
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Re: kitchen shot

Post by gustavoeb » 07 Mar 2012, 16:53

This is the image created only with the local samples at 1 technique...
Min 0.5
Max 10,000
Quality 15
Cuttof 0

Rendertime was 48 minutes (not too big of a difference it seems and it actually looks better). But having quality over 1 still boggles me, that should not be the way to do stuff...
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Kzin
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Re: kitchen shot

Post by Kzin » 07 Mar 2012, 17:08

gustavoeb wrote:This is the image created only with the local samples at 1 technique...
Min 0.5
Max 10,000
Quality 15
Cuttof 0

Rendertime was 48 minutes (not too big of a difference it seems and it actually looks better). But having quality over 1 still boggles me, that should not be the way to do stuff...
i use way less max samples normally, 250 to 600 for example, but with quality values ranging from 6 to 15.
from the scenes i had until now, it made more sense to use higher quality values. BUT this depends on the shot, the amount of mb you have to render.
so its really good to get some more examples here.

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ActionArt
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Re: kitchen shot

Post by ActionArt » 07 Mar 2012, 17:12

I tried setting FG at 200 rays and 15 points and reducing reflection bounces to 2. Here's the results:

3 minutes on a quad core:

Image

Still a bit grainy but that could be fixed with some tweaking. Most of the strange noise is gone I think.


With reflection optimization active on the back wall and main pot (default setting of 2). 2 Minutes.

Image

You might want to optimize from there. I think your biggest enemy was the reversed FG settings.

Don't have much time to test but will do more later.

Kzin
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Re: kitchen shot

Post by Kzin » 07 Mar 2012, 19:06

so, i opened your scene and there 2 things which are not that good.
your gauss filter witdh is 1,6. this is very low and will create a really sharp render. to render this with clean aa you will need a lot of aa samples.
the second, lambert like shading with your portal lights shows a noisy rendering. to clean this up you would also need alot more aa sample. so booth things should be changed first.
will now take a closer look. :)

Kzin
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Re: kitchen shot

Post by Kzin » 08 Mar 2012, 09:15

Image

rendersettings are a bit to much, but you want smooth glossis, so ... ;)
i also used the 1 sample approach, because the aa settings are very high, so it makes no sense to use local samples greater then 1.
min 1
max 1600
quality 20
treshold 0.03

rendertime is 25 minutes on my core2quad @2,667ghz and 16 minutes for fg. fg is calculated for the whole 1k render and then loaded from disk (500 rays, 25 int point, denstiy 2 and 1 diffuse bounce).
at the moment i render out a 720p version of the whole image to judge the rendertime.
sampling is really high, i would not use such values for animation or stills but values more like i write some post above and quality is more then enough also with these settings.

from your scene setup, you did also one mistake. you used low intensity lights and activated the lens shader to bring back the brightness of the scene.
you should never do this, dont use the tonemapper to correct your lighting (i rendered without one).

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Maximus
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Re: kitchen shot

Post by Maximus » 08 Mar 2012, 11:31

Kzin wrote:Image

rendersettings are a bit to much, but you want smooth glossis, so ... ;)
i also used the 1 sample approach, because the aa settings are very high, so it makes no sense to use local samples greater then 1.
min 1
max 1600
quality 20
treshold 0.03

rendertime is 25 minutes on my core2quad @2,667ghz and 16 minutes for fg. fg is calculated for the whole 1k render and then loaded from disk (500 rays, 25 int point, denstiy 2 and 1 diffuse bounce).
at the moment i render out a 720p version of the whole image to judge the rendertime.
sampling is really high, i would not use such values for animation or stills but values more like i write some post above and quality is more then enough also with these settings.

from your scene setup, you did also one mistake. you used low intensity lights and activated the lens shader to bring back the brightness of the scene.
you should never do this, dont use the tonemapper to correct your lighting (i rendered without one).
Interesting. I'm going to try what you suggested, i'm a bit concerned about tonemapper. How you light your scene without it then? Since portal lights are a pain to handle without exposure they blown out everything. How did you light the scene without it? If i remove the photo exposure all the lights in scene are blown out and really high in intensity, dunno why you said i had low intensity lights, they appear way too strong to me without the lens.

Thanks again for help

Kzin
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Joined: 09 Jun 2009, 11:36

Re: kitchen shot

Post by Kzin » 08 Mar 2012, 12:00

Maximus wrote:
Interesting. I'm going to try what you suggested, i'm a bit concerned about tonemapper. How you light your scene without it then? Since portal lights are a pain to handle without exposure they blown out everything. How did you light the scene without it? If i remove the photo exposure all the lights in scene are blown out and really high in intensity, dunno why you said i had low intensity lights, they appear way too strong to me without the lens.

Thanks again for help
your scene without lens shader renders really dark. i work linear all the time with display gamma correction. you did the gamma 2,2 correction thru the lens shader, your the problem is that also if you output to exr, you bake the gamma 2,2 curve in the image file. perhaps your workflow is the problem here?
if you work linear and with real light intensitys, its not a problem to get correct lighting without lens shader (phys sky gi renders are a bit different, you would end up with a nearly white render, so its best to use a tinemapper here). but you can lit a room really good without the lens shader with proper linear workflow and correct intensitys. also the portal lights are renders with plausible light falloff without to blow out the lighting.

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Maximus
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Re: kitchen shot

Post by Maximus » 08 Mar 2012, 12:16

I use the 2.2 on photographic exposure when i'm inside softimage to see how the render will look, but before i write image to disk i swap it back to gamma 1 and save out to exr.
I have no idea what you mean as real light intensity regarding portals and lights in general. The only real light you can get inside soft afaik are IES, and i'm not usin them here. I must admit i'm totally confused now. Can you share the scene with the lightin setup?

Kzin
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Re: kitchen shot

Post by Kzin » 08 Mar 2012, 12:38

Maximus wrote:I use the 2.2 on photographic exposure when i'm inside softimage to see how the render will look, but before i write image to disk i swap it back to gamma 1 and save out to exr.
I have no idea what you mean as real light intensity regarding portals and lights in general. The only real light you can get inside soft afaik are IES, and i'm not usin them here. I must admit i'm totally confused now. Can you share the scene with the lightin setup?
with real lightintensitys i mean physical light with falloff. you have then intensitys of 500 or more. the reflection of these lights will look way more realistic compared to the old "1 for intensity" lighting method. portal lights are best with some env shader from which they get their intensitys and color. so a realistic high contrast hdr will always produce a more realistic lighting inside a room (beside the fact that portals are only some sort of importance sampling for fg). and with good contrast from outside you will have good contrast inside.

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