Exterior wip

[Chakib]

Hi all,

I'm working on an exterior scene lately and i wanted to render it using Corona to test, so after converting and checking all materials, and here is the result.

Problem : the renders took 10 hours and the noise stills here :( i know i have poor cpu : core2quad q6600 )

I used :
Raytracing core : Embree tris : Precise
Low thread priority unchecked

PT-hd cache
path tracing samples : 16
max sample intensity : 10
Max records : 8000

So any tips to optimise speed  and clear up the noise would be  a big welcome !

[lacilaci]

are all those lightsources encapsulated in fully closed object with refractive material? I see at least one that seems to be enclosed in the interior... situations like this might be a part of the problem. I would lower down max sample intensity to 3 and increase light samples to 4... what version do you use?

[Chakib]

are all those lightsources encapsulated in fully closed object with refractive material? I see at least one that seems to be enclosed in the interior... situations like this might be a part of the problem. I would lower down max sample intensity to 3 and increase light samples to 4... what version do you use?

If you mean the exterior sphere lights : No they don't have refraction materials they are just simple emission material.
I use the legacy latest build for 2013 in the dropbox ( daily builds )

[lacilaci]

hm... don't know. But I'm working on a similar exterior scene with corona right now so I guess I'll soon be in the same situation myself... did you try pt+pt and bidir?

[Chakib]

hm... don't know. But I'm working on a similar exterior scene with corona right now so I guess I'll soon be in the same situation myself... did you try pt+pt and bidir?

No, will test them tonight
maybe the openexr envirenement map  is the problem, i will test a simple corona daylight sun and see if it helps

[Ondra]

definitely try increasing the direct lighting sampling multiplier

[Ludvik Koutny]

This could be related to the opacity bug...  that produces intense grain... 

[Chakib]

definitely try increasing the direct lighting sampling multiplier

tested it ( increased to 6 ) and after an hour it seems that it doesn't help much :s

[Chakib]

This could be related to the opacity bug...  that produces intense grain...

i think you're right because i did use the opacity map for the trees leafs, do you think it's the problem source?

[Ludvik Koutny]

Most probably, similar scene should take about 30 minutes to get reasonably clean on an i7 machine...  so maximally an hour on quad ;)

[Chakib]

Most probably, similar scene should take about 30 minutes to get reasonably clean on an i7 machine...  so maximally an hour on quad ;)

that's what i've told myself because an interior scene was clean in 2h with the q6600 so logically the exterior should take less than interior rendertime.

Also i forget to mention that the leafs have the transluency +opacity+ reflection+ bump.. lol will delete them and see the result

[Chakib]

Here is a 30 min render with daysystem corona without disabling the leaf opacity.

looks faster than the night version.

Problem : weird white dots in windows ! maybe because i did decrease the max samples intensity to 3.

second remark : the sun intensity is set to 1, but hete i see that the sun intensity is a little bit low, should i increase the intensity of the sun or leave it alone ?

[michaltimko]

dots = low MSI, try to increase or let it cook longer. If  you set PT+PT with MSI 0, corona is running in unbiased mode

And yes, you can set sun multiplier to any number, also try to play with sun size, bigger sun is producing nice smooth soft shadows.

[lacilaci]

Well I got the same problem now. I'm working on an exterior too and I'm too using latest legacy build and it seems that it is indeed related to opacity since I'm having weird bright dots on screen when I render trees with opacity mapped leaves. When I turn off opacity then it works as expected....

[lacilaci]

Ok... Forget what I just wrote.. My problem seems to be elsewhere. Turning off opacity did just greatly reduce the defect, but I'm still getting some bright dots. I guess it's the material (possibly reflection cause turning off translucency didn't help) testing different settings now.

[lacilaci]

Alright. So my problem was the sun reflection. Even tuning reflection level down from 1 to 0,2 on tree leaves gave me very bright dots that looked like some bug happening there... Is it possible that in your case you are having these bright dots because of reflection of light sources?? Do you have any if you render it just using corona sky?

[Chakib]

I agree with you lacilaci , i updated the scene : removes all opacity + increased the MSI to 10 (even to 20 ) + increased the light samples :

The white dots are still there even worst this time, look at this 20 min test, maybe the legacy build only have this bug?

[Chakib]

No  they are everywhere now not just light sources lol, i disabled the sunlight and used this time an envirenement light source, but it's worst now.

just to mention what corona version i used :

Defines:  LEGACY  STATS
Internal color space: CIE XYZ
Build timestamp: Nov  2 2012 16:58:26
Max version: 2013

i use the one in the assets folder, is it buggy than the release version?

[lacilaci]

as far as I know the assert version should be only slower, but otherwise the same as release. But try the release one just to see

[Ludvik Koutny]

This is definitely not a low performance issue but a bug...  it should never take this long... The problem with opacity grain has not been fixed yet...  I will let you know once it is so you can grab very recent build to test :)

[michaltimko]

Can you post screenshot of render settings ?

[lacilaci]

Chakib... are you using direct color mode on your lights? If yes then change the color from default 255,255,255 to lower... try 220,220,220... and without sun... and see if there still are those overbright dot's... I haven't tested this my self now... but I think that visible light source in reflection with max white value could cause this overbright dots effect and could indeed impact performace... I'm putting together an exterior scene myself and for me the sun was causing these dots and it was slower a lot.

I'm using no lights just an hdri and everything works pretty much as expected.. The performance isn't perfect but no overbright dots

[Chakib]

This is definitely not a low performance issue but a bug...  it should never take this long... The problem with opacity grain has not been fixed yet...  I will let you know once it is so you can grab very recent build to test :)

Ok i'll wait guys for your next release thanks !

[Chakib]

Can you post screenshot of render settings ?

here : http://forum.corona-renderer.com/index.php/topic,279.msg1859.html#msg1859

but i've changed the MSI to 10 instead of 3.

[Chakib]

Chakib... are you using direct color mode on your lights? If yes then change the color from default 255,255,255 to lower... try 220,220,220... and without sun... and see if there still are those overbright dot's... I haven't tested this my self now... but I think that visible light source in reflection with max white value could cause this overbright dots effect and could indeed impact performace... I'm putting together an exterior scene myself and for me the sun was causing these dots and it was slower a lot.

I'm using no lights just an hdri and everything works pretty much as expected.. The performance isn't perfect but no overbright dots

No the color of the lights are less than 255 i always take that into consideration in any render, and there is no sunlight just hdri too, so i think it's a bug for sur like Rawalanche said.

[andreupuig]

This dots sound strange, when I rendered exteriors, night and late afternoon, of the theatre I never get those dots.
I was using coronaSky, coronaSun, mesh lights and there were a lot of extremely blurred reflection, but never had random white dots, even in first test. I had some noise on blurred reflection materials that is not your problem.
Did you tried to render without glass object? Not hide to camera or similar, just hide the objects.

[lacilaci]

Yes it seems so far that there is a bug causing this. But I still can't see how would this, these white dots on that render, be related to opacity mapping.

[lacilaci]

2 of my early tests (don't mind the weird scattering).... Both about an hour originaly in 1080p. So yes it's slow, it's grainy, the opacity is not working very good but without sun or additional lights no white overbright dots... With sun or additional light sources there are dots all over the place even without opacity maps being used.... So I guess we have to wait for some update.

[michaltimko]

I never had dots guys...also those images looks like without AA.

[Paul Jones]

Looks strange, could you post a stripped down scene? Had grass work ok here as while back :)

[Chakib]

Here is a result of PT+PT instead of HD cache

Always dots ! i think this bug is exclusive to the legacy build since the build daily updated for the newer processors doesn't have this bug ( fixed i think ), maybe i'm wrong.

[lacilaci]

This is sooo baad.... How does it look if you turn all the vegetation, grass, trees off?? Have you tried?

[michaltimko]

thats weird...

can u send zipped max file ? or its commercial project?

[Ondra]

There is similar bug reported in Mantis, I'll look into it once I have the time. It should not be hard to fix.

[Chakib]

This is sooo baad.... How does it look if you turn all the vegetation, grass, trees off?? Have you tried?

No, will try this tonight

[Chakib]

thats weird...

can u send zipped max file ? or its commercial project?

no it's a personal one, but the problem is the size of the file is very big

[Chakib]

Now i did delete all scatter plants and trees and light in the scene and keep just the hdri as light source

result : very fast clean 15 min render

the trees and plants don't have opacity at all, maybe the cause is the corona lights and their effect on the glass material.

[michaltimko]

those windows...material (glass) is set to Solid or Thin ?

[Chakib]

those windows...material (glass) is set to Solid or Thin ?

They are thin since the solid doesn't work good for windows.

the glass windows object is not one face, should i apply the thin glass to one face object to get it work good or it's not important that i apply it on a "box" objects ?

[michaltimko]

thin is ok with box...

[lacilaci]

I'm using single sided faces and twosided material... However let's hope keymaster finds some time soon to get us around this issue and if it would improve performance aswell it would be awesome :)

[Ondra]

Looks like I've fixed the bug ;)

[Chakib]

Looks like I've fixed the bug ;)

You mean with VCM ?

will test it now and see the result ! Thank you Ondra !

[Ondra]

The bright spots when using opacity/doublesided glass

[Chakib]

Ok, here is a test render that i did for the three modes :

Bidir : 37min
Progressive : 42 min
VCM : 1h16min

No Opacity here !
------------------------

Bidir :
- Fast render start
- Fireflies everywhere, it's chaos !
- Ground material is black ? weird...

Progressive :
- Very slow render start
- Fireflies !
- Ground material is OK !
- Curtain materials is not affected by light... weird !

VCM :
- Little bit slow render start
- No Firelfies ! ( maybe i'm wrong but i see some little ones on floor and walls... maybe i should give it more time)
- Ground material is black again ?


Conclusion : VCM is doing a pretty good job here but the noise needs more time, i hope it will be faster than now and also the ground material here i don't know what's wrong with it since it renders good in Progressive mode.

Next test : Trees with/without Opacity.

[Ludvik Koutny]

You don't have your light sources covered by a glass, right?

[Chakib]

You don't have your light sources covered by a glass, right?

The glass balls ( with corona spheres lights outside of them ) are with glass yes since i used a daylight scene so i kept its material, is that the problem ?

[Ludvik Koutny]

You don't have your light sources covered by a glass, right?

The glass balls ( with corona spheres lights outside of them ) are with glass yes since i used a daylight scene so i kept its material, is that the problem ?

Could you try to render night scene again with latest nightly build and without any glass objects in the scene?

[lacilaci]

Chakib is using legacy build. Latest legacy 2012-12-05 still has the bug causing dots/fireflies from lightsources in this kind of scene, you can see that in my recent wip here. I guess keymaster fixed it later..??

If that so. I would like to try that fix myself too if keymaster finds time to compile legacy build :)

[Chakib]

Could you try to render night scene again with latest nightly build and without any glass objects in the scene?

Will try that... i must  remove the windows glass material ?

[Chakib]

Chakib is using legacy build. Latest legacy 2012-12-05 still has the bug causing dots/fireflies from lightsources in this kind of scene, you can see that in my recent wip here. I guess keymaster fixed it later..??

If that so. I would like to try that fix myself too if keymaster finds time to compile legacy build :)

Yes i use legacy latest one you mentionned , keymaster told me that it's fixed so i did this test and i think VCM is doing fine removing fireflies ( not all of them i guess )

[Ondra]

it's not in that one, I'll make new legacy builds eventually

[Sam75]

aren't you using one sided glass material ?

[Chakib]

it's not in that one, I'll make new legacy builds eventually

Thanks Ondra, you rock !

[Chakib]

aren't you using one sided glass material ?

No i use two sided.

[Sam75]

aren't you using one sided glass material ?

No i use two sided.

I am not talking about the geometry but the material refraction option

[Ondra]

new legacy builds are up BTW

[Chakib]

new legacy builds are up BTW

ok will download it and test the night scene right now

[Chakib]

Ok guys here is another test of the full night scene this time with trees and lights.

i use the latest 2012-12-07 legacy release build.

The trees have : Translucency + Reflection + Opacity
Grass have : Translucency + Reflection ( no Opacity )

VCM doesn't render the blend material : so i did use only one ground map.
VCM also can't render the corona elements ( too early i think to add )
Light in VCM mode  appears even if the light is not visible ( that explains the huge light balls on the grass, there is sphere emitters inside the light spheres )

Ive tested Progressive and Bidir : it was a fireflies chaos, no way !

But the VCM here did the job even if i see some little ones .

Problem : the time is 12H to render and we still see noise :S !

[hglr123]

12 h for exterior render? Wow, this is too much I think. And still a lot lot lot noise.

BR!
Nik

[Ondra]

12 h for exterior render? Wow, this is too much I think. And still a lot lot lot noise.

BR!
Nik

unfortunately VCM is no good for such type of scenes

[Chakib]

12 h for exterior render? Wow, this is too much I think. And still a lot lot lot noise.

BR!
Nik

Yes you're right its too much time with too much noise sadely, the progressive mode have a lot of fireflies in this scene and bidir is worst

i think i'll wait for the next alpha/beta release with hope, i'm tired with this scene lol

[Chakib]

unfortunately VCM is no good for such type of scenes

yeah but the light is reacting good with vcm here, but in another scene of a simple glass cup( i'm working on it ), the light with progressive mode is better than vcm and bidir :S

i want to send you the scene but it's a 700mb size file :s will try to delete some models inside.

[Ondra]

I could actually use some scenes where VCM/bidir fails. We are currently trying to improve it in our project. If you have any nice scene where it/path tracing does not work, send it to me. They only cannot contain much fakes.

[Chakib]

Back to test this scene with a work around ( thanks to timko ) and it seems that the fireflies are gone with Pt-Pt progressive using  the latest legacy nightly build.

instead of using environment slot i did use a hemisphere mapped with an hdri ( the old way )

But it takes a lot of time to render it for an exterior scene, maybe because of these many proxies...

Here is the result of 6 hours of rendering and  still noisy but no fireflies i guess :

[michaltimko]

Its still quite a lot of time. Maybe one thing you can try is to use only HDR in env. slot and corona lights (hide no materials with emission enabled in scene).

[Chakib]

Its still quite a lot of time. Maybe one thing you can try is to use only HDR in env. slot and corona lights (hide no materials with emission enabled in scene).

i will disable the emission in the outdoor spheres and see the result.

[lacilaci]

Did you try setup with very high values for light sample multiplier?? I'd try with 16 samples for PT and 32 for lights seeing this result..

[Ludvik Koutny]

Could you just for fun try to set light samples multiplier to 0, and then also try to set light solver to simple? Just for fun :)

[Chakib]

Did you try setup with very high values for light sample multiplier?? I'd try with 16 samples for PT and 32 for lights seeing this result..

light samples is set to 6 lacilaci, i will test with higher values

[Chakib]

Could you just for fun try to set light samples multiplier to 0, and then also try to set light solver to simple? Just for fun :)

will do with different values.

"for fun"?

is that related to my penguin render?

it's not "fun" to see such bug you know... thank you for your help anyway

[Ludvik Koutny]

Changing these things will alter the way lights are sampled. By "for fun" i mean that i do not believe it will make much of a difference, but that it's still at least worth trying, because even if it doesn't do much good, behavior of Corona after these changes could at least point us to the direction where the bug comes from ;)

[Chakib]

Changing these things will alter the way lights are sampled. By "for fun" i mean that i do not believe it will make much of a difference, but that it's still at least worth trying, because even if it doesn't do much good, behavior of Corona after these changes could at least point us to the direction where the bug comes from ;)

i do my best to help here with my tests so we all can figure out where it did come from, timko do also work on it, we all here doing this,  i'm not here "just for fun" ;)

[Ludvik Koutny]

Ok, to explain once again. Phrase "for fun" was not related to you personally in any way. What i meant by it is that it was not an official advice, it was just a simple test to see what happens, not a verified solution. That's what i meant by "for fun" :)

[Chakib]

Ok, to explain once again. Phrase "for fun" was not related to you personally in any way. What i meant by it is that it was not an official advice, it was just a simple test to see what happens, not a verified solution. That's what i meant by "for fun" :)

ok no problem bro I'm sorry if i misunderstand you :)

since something wrong with this scene i will optimize the size so i can upload it to you guys to test.