Chaos Corona Forum

General Category => [Archive] Chaos Corona for Maya => Porting and API => Chaos Corona for Maya - Bugs => Topic started by: Eian on 2015-05-20, 21:47:39

Title: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-05-20, 21:47:39
Hey Haggi,

Well done on your last release. Areal lights working properly now.
Though when I connect a texture to a to a surface through coronaLight material, I still get strange results as you can see on the image attached.
Problem occurs in progressive and bucket rendering mode as well.

Another thing I noticed with Maya 2016 is that if I save a rendered image as an openexr it wont save its gamma settings correctly.
That applies regardless of the color management setting under Maya's preferences.
Now this might be a Maya problem cause it happens with other renderer as well but I believe there might be a way you can fix it.
Only workaround I found working, is to change Colormapping_gamma to 1.000 and then save the image. And btw saving raw / color managed mode does the same thing.
So even if this is a maya problem maybe you can force a Colormapping_gamma of 1.000 just before saving the openexr image?

As you pointed out CoronaVFB is really experimental at this stage and due to constant crashes I can't say much as of now.

Keep up the good work!

Regards,
Ian
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-05-21, 10:17:14
Could you please clarify the exr problem a bit?
Do you save the rendered image directly from the renderview? Or do you mean the automatically saved image from rendering which can be found in the images directory? The rendered image will always be saved in the images directory. And if it is an exr, color correction is used, but gamma will be set to 1.0.

The image in the renderview contains gamma from color mapping. I will change the default settings for maya2016 so that by default in a new scene the gamma will be set to 1.0 what should be better because by default Mayas ColorManagement is turned on.

At the moment there is no way to save a raw - non color mapped image (except gamma). But it should be possible to implement it if needed.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-05-21, 18:17:14
Oh I forgot to check the image output through the render settings and now that I did I see that it works just fine!

So the problem only occurs when saving through the renderview!
Though I wouldn't recommend you changing the default colormapping_gamma to 1.000 cause it will affect the quality of the rendered image which makes sense cause when a lower gamma is used the renderer will not refine the darkest areas. So when you apply the correct gamma of 2.2 you will get more noise in the darker areas.

As of now by turning off maya color management and saving through the render settings works fine.

Regards,
Ian
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-05-22, 00:17:45
Gamma does not affect the quality of the rendered image. I simply want to avoid double gamma in maya2016 what is the case if you use color management in maya what will be the default because is simply gives better results.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-05-22, 19:47:57
Hey Haggi,

I understand you want to avoid double gamma correction and seemingly it comes to your preference what the default settings will be, they can be changed anyway.

Generally speaking, I won't post something before I test and as shown in the images attached, gamma setting (when chosen through the render settings) affects quality of the image, sometimes less sometimes more depending on the lighting.
V-ray has a setting for that as well, called "adaptation only" which allows the renderer to proceed with all its calculations as though color mapping is applied without applying color mapping so that the noise levels can be corrected accordingly.

In the images attached the one rendered with a gamma of 2.2 has less noise and was done in less time even though all the other settings were identical.
The image named "Gamma 1.0 to 2.2" is identical to the first one which was rendered with a gamma value of 1.0 and then corrected to 2.2 in post.
Difference might be small but is surely there.

Regards,
Ian
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-05-25, 14:46:03
In Corona the color mapping settings have no influence at all on the rendering process. The image is rendered and then after rendering the color mapping including gamma are applied to the framebuffer. So all noise or other elements you see in the image with gamma 2.2 are already in the image with gamma 1.0 but they are less visible because they are darker. So if you need to adjust the image quality, then you simply apply the appropriate gamma (2.2 in Maya2015 without mayas color management) and do the rendersettings in a way quality is good enough.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Ondra on 2015-05-25, 18:12:42
actually some parameters (like MSI) are influenced by the initial exposure value, so you should not change exposure much after you start rendering
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-05-25, 19:21:28
Thank you Ondra.

I can understand haggi's misunderstanding on the subject, because theoretically gamma is applied after the rendering process but in reality it seems this is not the case as you just explained.

Attached is a better example to show the difference. Again in one image gamma correction is applied after the rendering, and on the other before the rendering.
I must also note that I'm using bucket renderer to better illustrate the difference because supposedly progressive mode doesn't use adaptation as much hence the result should be similar.
All the other settings apart from Colormapping_gamma are identical.

Kind regards,
Ian
Title: Re: Corona 0.41 (Maya 2016)
Post by: Ondra on 2015-05-25, 19:35:58
well gamma should not play role - just exposure ;)
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-05-25, 19:46:44
Hey Ondra,

Hmm I see but why is there a difference on the images I tested? I just changed the Colormapping_gamma setting not the exposure.
Could it be that the Colormapping_gamma setting is somehow unintentionally related to exposure?
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-05-25, 19:57:03
Could you please send me this scene? I just tried to reproduce the effect with one of my more complex scenes and the images were identical.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-05-25, 20:18:53
Hey Haggi sure!

Btw are you using bucket mode? As I said on my last post due to the fact that progressive mode does not use adaptation refining methods (Adaptive Threshold), the results should be the same if not identical when using progressive mode.

So my initial point was that the "thinking" of the renderer gets affected by the Colormapping_gamma setting whether that should happen or not.
You just have to use certain settings in order to see it though :).

Attached is the scene.
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-05-27, 00:00:02
Okay, you are right. I tested it in maya2015 and there is a difference. If I set the gamma before rendering, rendertime is 3:18min. Setting it after rendering results in more noise and a rendertime of 1:55min. But I did not get any difference in brightness which appear in your images.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-05-27, 00:44:34
Hey Haggi,

There is no brightness difference in my images either.
Bottom images might seem brighter due to the viewing angle of your monitor. If you download them and open them sequentially you will see no difference in brightness ;)
Anyhow no problem with exr gamma if I use the image saved through the render settings.

Any progress on the texture lighting issue? It would be great if you could fix in your next release! :)

Kind regards,
Ian
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-05-27, 09:41:03
Sorry, still no idea what's happening with textured lights at the moment.
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-20, 16:57:24
Hi Haggi,

  I've noticed a weird bug too.  It seems I can't place a utility node between a file map and the reflectionGlossiness attribute of the Corona Surface - except a contrast utility node.

  I have tried to color correct my glossiness map by all means with any utility node, without success.  Normally I would use a remapValue but since they are not supported I tried RGBtoHSV, Clamp, and a few other but none is working.  Only the contrast uility is working as expected.

  The file map works fine if I plug it directly in the shader, but not when there is a utility node between.

 
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-20, 19:00:58
Also the area lights block other lights behind.  I cannot have a corona sun with area lights in the windows, the area lights block the light from the sun.  Maybe an option to let light pass through would be cool.

Another useful feature would be to expose the Corona tab / properties of lights in the channel box.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-09-20, 20:37:56
Hey RickToxic,

In order for the area lights to work the way you described, you need to enable "Use as Environment Portal" under "Corona" in the light shape attributes.
Normally this gives you a performance benefit but I'm not sure if its working properly cause after a quick test I just did I didn't see any performance gain.

Seems you're right about the utility node issue though.
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-20, 21:04:02
Yes but I don't necessarly want those lights to cast the environment lighting...  I would like to use them as regular (white) lights.

I thought about using mesh lights and disable cast shadow, maybe that would be a possible workaround.
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-21, 17:58:40
Normally this gives you a performance benefit but I'm not sure if its working properly cause after a quick

Me neither, I haven't seen any gain in terms of noise and speed with portal lights - both for meshes and lights.  I thought it was specific to my scene but if you experience the same issue it might not be then : )
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-24, 22:24:17
I guess this is already known, but the mirror U and mirror V features of the place2DTexture are not supported yet?
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-09-25, 00:25:33
Yeap.. Actually texturing implementation in general seems to be a bit buggy..
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-09-26, 20:00:12
The shadow casting of area lights is fixed in the next release. And I'll have a look why you cannot place a utility node between file and attribute. As much as I'm aware color remapping should work, all necessary nodes are supported.
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-27, 02:25:01
Hi Haggi!

  There is a new utility node extremely useful in Maya 2016: color correct.  It does what all the other nodes (remap value, remap hsv, gamma correct, contrast, etc) do in one super node, and it was a very long-awaited feature in maya.  Right now I think it's not supported by any renderer except mental ray, but surely this will become the most used utility node after place2d, maybe you can add it on your list for one of the next releases!  : )
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-09-27, 20:42:21
Ah, okay, this node ist not yet supported. I'll see what I can do as soon as the current updates are done.
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-27, 20:55:34
Nice!!

I must admit though that not many people know about it yet I think....  I only found about it by digging in the docs on new features on Autodesk's website.  But I am sure people will use it all the time, just like they do in 3Ds Max with the same node.  It's the most useful node for sure.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-09-28, 18:56:32
Very good to hear progress is being made!!

Haggi are we by any chance seeing interactive rendering implementation any time soon? I think its really important..
Also the new displacement features are more than great!

RickToxic great remark, indeed those new LookdevKit nodes are awesome!
The were added in the extension 1 and one needs to enable LookdevKit.mll plugin in order to access them.
There is a great new simplexnoise node as well which I think does not work in the current corona plugin either.
Seems a bit strange that they were added in the extension and not in the major release.
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-09-28, 21:00:11
Interactive update will not make it into the next release. I'm working on the new hypershade material editor implementation what is a small version of interactive rendering. If it works as expected, I can translate the procedures to the IPR. Displacement and other features will be in the new release.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-09-28, 21:23:17
Ok good to know!

Keep up the good work!
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-29, 01:46:50
Hi Haggi!  I am trying to render with Corona this scene that I rendered with another render.  The scene is pretty light, but has hi-res (4K-8K) png and jpg textures.  I have maybe 20 maya area lights, 9 materials, 1 sun and 1 exr environment.

When I apply a white material on everything, the render starts right away, but with my textures it takes more than 20 mins to start the render - it stays in the g.i. phase (or idk how you call it) almost forever and produces only 50-100 rays/s.

If I apply one material at the time on all objects the scene works (the calculation phase takes between 30s-1mn), but with all applied it looks just too much for the system (a recent laptop, should be fine!!).

Is the texture memory handled differently than the other software / plugins, or is it mandatory to use mipmaps with 8k textures with Corona?...

Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-09-29, 09:57:15
In theory, this behaviour is expected with large textures and the usage of OpenImgeIO. If you do the same in Arnold, you will get a similiar slowdown. Exactly for this case the tx files should help to reduce memory demands and speed up the rendering. But I have to admit that the implementation of OIIO may not be optimal.
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-29, 13:52:25
Hmm...  I tried a render yesterday, after 45 mins I was not seeing the form of the building...  The thing is that in the calculation phase, the performance can go as low as 0 to 5 rays/s.  After 45 mins, the rendering phase had not started yet.  I know the textures are big, but I consider this to be a fairly light scene.  As for the textures they are mainly Arroway textures and are part of my everyday work - and specifically targeted at archviz.

Personnally I have no problem converting to tx as it is a standard procedure in vfx, but usually in archviz we work more with texture libraries...  Also, not being able at all to work with jps and pngs at 8k can be a big thing, I always considered tx files to be part of an optimisation process, not a necessary step.

Btw, for the future, I'm never criticizing, just trying to help make a better world : )
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-09-29, 16:07:12
You are right. The procedure is not optimal at the moment. I suppose you tried to convert the 8k textures to tx files and you did not see any speedup?
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-09-29, 16:12:45
Nope.  I will try it later today or tomorrow to see if it changes the performance, especially in terms of ray/s during the calculation phase.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-10-11, 00:05:11
Hey haggi,
I just tested the new Corona plugin for Cinema4D and found out that there is a precision setting for UHD Caching. It ranges from 0 to 99 impacting performance and GI accuracy. After playing a bit I saw that when set to 0, GI is far from correct. At 1 which is the default is pretty good and after 2 there is very subtle to no difference compared to 99! Now as far as performance goes, when set to 0/1/2/3 the impact is minimal to none but when set to 50 or 99 it performs about 30% slower and also has a bit more noise for the same number of passes.
I wonder what's the default setting for this option in Maya's plugin?
From the time it takes to precalculate the same scene seems like around 10.
Now I didn't go too deep with this setting so I might be missing something but maybe a lower setting would be faster with no visual impact.
Is this option going to be there in the next version of Maya's plugin?

Regards
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-10-11, 19:22:02
A lot will change in the next version. The precision attribute is one of them. I have no idea which was the default in the old version, but now it is 1.0 and you can set it as you like.
Title: Re: Corona 0.41 (Maya 2016)
Post by: Eian on 2015-10-11, 19:55:51
Good to know.. Any information on release date? :)
Title: Re: Corona 0.41 (Maya 2016)
Post by: haggi on 2015-10-12, 23:25:47
If everyting works fine, tomorrow.
Title: Re: Corona 0.41 (Maya 2016)
Post by: RickToxik on 2015-10-12, 23:30:06
yeepeeeeee!!!!!