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Test lighting

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Test lighting

Post Tue Jun 26, 2012 11:23 pm

hello, here I show a render in light of the type Yafaray sun and Portal light bg,hear your comments
Attachments
yafaray.jpg
Yafaray
vray.jpg
Vray
davidq82
 
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Re: Test lighting

Post Thu Jun 28, 2012 12:06 pm

Vray look realy nice.
As more as go into the room, as more it looks better then yafaray.

But maybe you could get the samew result if you use a better lightning setup in yafaray.
Malo
 
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Re: Test lighting

Post Fri Jun 29, 2012 8:48 am

Whats the rendertime of each ?

In the Yafaray-Version it's to bright behind the Monalisa.
I guess you have to improve the Yafaray-Settings.

Can you test it with Cycles (GPU) as well (I will do it for you if you send me the Scene) ?

Kind regards
Alain
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Re: Test lighting

Post Sat Jun 30, 2012 2:14 pm

davidq82
 
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Re: Test lighting

Post Sun Jul 01, 2012 1:01 am

the main issues in your example:

1.- The Big Plane as Background in your scene creates a shadow and remove photons from the Sun lamp and Skylight:
a better option is to remove the plane, save the final render as RGBA premultiplied and add the background in postproduction
2.- The 3D models are screwed up:
a.- horizontal lines are not horizontal
b.- the white dots in your render are actually the result of lack of thickness of floor, walls and
ceiling plus all screwed up geometry (read point a). With Yafaray is always better to create real
geometry avoiding to work only with planes.
3.- Sun lamp power 30?: Really?. Usually power 1 to 2 is enough. Adjust levels later with tonemaping.
4.- Tonemapping: Always save a copy in exr or hdr. In that way you can adjust the levels in post
production without the risk of loosing details.
5.- Normals: check the normals for all the geometry (read point 2)
6.- In real life there is no pure Black colors: try changing the black level to something like
(0.001,0.001,0.001)
7.- In real life there is no pure White colors
8.- In real life there is no 100% reflections
9.- Depth 50?!: 6 to 8 is enough.
10.- 30 render passes and 16 FGsamples?!: 64 FG samples for final render and 8 to 16 render passes
with 2 samples per pass is usually a good strategy.
11.- The shadows in the background image do not match with the Sun lamp direction from the scene and that make the image to look fake
12.- (not really an issue) BGportal power =2: I personally prefer power=1 when used with Skylight

With all that I tried rendering the scene making some changes. Some of the textures (Background, Monalisa, Sailing Boat) were not packed in your blend file so I imporovised with the closest imageas i found. The final render was saved in EXR format and tonemapped with Luminance 2.3 Beta1. Postproduction with GIMP. You can see that in my case the original render is too dark but with a HDR format you have access to a wide dynamic range to play with. Of course the postproduction process and color correction is always a matter of personal taste.

BTW render time was 29 minutes with Photon Mapping + Final Gather plus 15 minutes for postproduction with Luminance and GIMP
Attachments
tonemapped.png
tonemap+postprodcution with Luminace and GIMP
original.jpg
default render without any postproduction

"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."

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condar
 
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Re: Test lighting

Post Mon Jul 02, 2012 4:38 am

I forgot to mention that the Vray render shows artifacts (blobs) close to the edge for wall and ceiling... Irradiance Cache Artifacts I guess.
Attachments
vray_Artifacts.jpg
Artifacts in Vray render

"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."

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condar
 
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Re: Test lighting

Post Mon Jul 02, 2012 11:28 am

Why is it so bright behind Monalisa ?

tonemapped.jpg


Kind regards
Alain
Intel Pentium 2.8 GHz 2 Cores, 8 GB RAM, GeForce GTX 480, Blender 2.63a, Win 7 64 Bit
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Re: Test lighting

Post Mon Jul 02, 2012 6:43 pm

Hi

Following the advice of Condar
this is my result

A changed the portals by area light
Attachments
My Test.png
Abner
 
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Re: Test lighting

Post Mon Jul 02, 2012 9:11 pm

Alain wrote:Why is it so bright behind Monalisa ?

Kind regards
Alain


oops! My fault!. :oops: For some reason I removed some geometry from that wall before saving the blend file and the render was using only a plane as a wall (screwed up geometry :P). That make the light leaks from the outside through the Wall (just a plane).
I rendered the scene again this time with proper geometry for Walls, floor and ceiling. ;)
Attachments
interior_ver2_final.png
EXR file tonemapped with Luminance 2.3 Beta1, postproduction with GIMP
interior_ver2.jpg
default render from Yafaray in LDR format

"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."

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condar
 
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Re: Test lighting

Post Mon Jul 02, 2012 9:23 pm

Abner, much better :)

Alain, you are absolutly right.

Condar, your advices are very important.
Your scene without previous issue is perfect.
I also agree with your vray IC observations.
Can you also share your post pro procedure in detail?

Once again, thank you all for sharing your work.
Arquitecto can be contacted here:
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Re: Test lighting

Post Mon Jul 02, 2012 11:21 pm

Arquitecto wrote:Can you also share your post pro procedure in detail?

Once again, thank you all for sharing your work.


1.- I usually choose tonemap in Luminance with all the operators available from the dropdwon list, using the inverse value of Gamma Correction in Yafaray as PreGamma in Luminance Interface.
2.- Then I just mix all or some of the tonemapped images over the original render using blend modes in GIMP (screen, Overlay, etc) and using layermasks if it's needed.
3.- AO pass (multiply) + Zdepth pass (inverse Screen)
4.- Add Background if it's needed
5.- Color Correction + some filter you like

BUT it's always a matter of personal taste.
Attachments
Luminance.png
Luminance Interface with PreGamma = 0.45
Tonemap_Operators_result.jpg
Tonemapped images from Luminance
GIMP.png
composing all of some of the images in GIMP

"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."

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condar
 
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Re: Test lighting

Post Tue Jul 03, 2012 10:12 am

:D
Thank you very much Condar.
Interesting aproach, in fact with lots of tonemapped images you don't loose information and you have light properties allways available on the gimp image.
An we definetly see that on the final image.
I still have one doubt.
You didn't make any AO pass and z-depth on the final image right? You were telling just your usual workflow right?
I am saying this because on production environment we need lens and some defocus, but doing it on yafaray or even vray is a never ending story to clean the noise... So I used to do it on photoshop. The last time I tried on gimp, i made a mask and then I used gaussian blur over the mask. But I wasn't quite happy with the results...Is this your usual aproach?

P.S.:Thanks again for sharing your knowledge. Suomi once explained his post pro procedures and I became quite surprised by his fantastic aproach. Rio had also a very nice different aproach. Post pro is a must on any good rendering and should be litle different from each render engine you use. For me it's not only taste... it's wisdom.
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Re: Test lighting

Post Tue Jul 03, 2012 7:13 pm

Arquitecto wrote:I still have one doubt.
You didn't make any AO pass and z-depth on the final image right?


Yes I did "3.- AO pass (multiply) + Zdepth pass (inverse Screen)" but not always needed. As a general rule try to get all render passes you can and then decide which one you can use. In this case Zdepth inverted and blended with Screen 10% just to give the image a little sense of Mist. But Zdepth can be used to add Depth of Field too. To get AO pass and Zdepth in Yafaray is very simple and it only takes a few seconds to render: just remove all lights from the scene, render with Direct Lighting, activate AO and Clay render (pure white color), change the World Color to Pure White and render. Zdepth pass is only available in Blender exporter IF you change the output method from "Into Blender" to "Image File".

Arquitecto wrote:I am saying this because on production environment we need lens and some defocus, but doing it on yafaray or even vray is a never ending story to clean the noise... So I used to do it on photoshop. The last time I tried on gimp, i made a mask and then I used gaussian blur over the mask. But I wasn't quite happy with the results...Is this your usual aproach?


nope. Gimp have the "Focus Blur" Filter that can use a Zdepth pass as source to blur the main image. You just load a Zdepth pass in a different layer and then use it in the filter, select the "focus distance" and all the image will be blured proportionaly to to the Zdepth information and the max Blur radius. You can do something similar with Blender Nodes but in GIMP the process is more flexible and quite easy. In Blender, the focus distance is tighted to the camera information and so you can not change it as you want with nodes.
As an example I added DOF to the final image with an exagerated Blur Radius (max Blur 40) an a focus distance on the Red Chair just to demonstrate how the filter works. It looks terrible :D But you can note how the blur is distributed over the image according to the Zdepth information and the focus distance. In this scene considering the camera focus, a blur radius 1 or 2 will be enough to get a nice DOF effect.

Arquitecto wrote:Suomi once explained his post pro procedures and I became quite surprised by his fantastic aproach. Rio had also a very nice different aproach.


if you think about it, almost all post production processes are the same in a general way. the main differences are basically in the software people use wich determine their workflow. As a Linux user, I only use Open Source Software and GIMP cannot handle HDR image formats...for now (16 bit color depth images support in GIMP will be added in version 3.0) so I use Luminance or pfstool/pfstmo for tonemapping as an intermidiate step before blend and color correct the whole image. On the other hand people using Phtoshop can use the EXR file directly (I'm not sure that the same tonemapping filters are available in Photoshop) and so their workflow will be different without the intermediate step of getting tonemapped images but tonemapping in the final step inside Photoshop.
Attachments
AOandZdepth.png
AO pass and Z-depth pass from yafaray
Focus_Blur_Filter.jpg
Focus blur filter in GIMP
DOF_example.jpg
exagerated foucs blur example

"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."

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condar
 
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Re: Test lighting

Post Wed Jul 04, 2012 10:14 am

:D
Thank you very much Condar!
This tutorial is so cool that could be sent to the tutorials section!
I Didn't knew I could make ao and z-deph pass with yafa.
I missed the output method change...

Focus blur is in fact a very nice filter.
Much better than my awfull aproach!
Your result is perfect! For testing purposes, of course! :D It looks like I am a giant looking inside a model :lol:
I also don't see any problem in missing 16 bit color deph on gimp post pro.
It seems gimp has much more potential!
And I must study it better... :wink:

Anyway, sincere thanks Abner for sharing your work, Allain for the critics, and Condar for the tuts!

P.S.: You guys do know the Mona Lisa real size, don't you? :lol:
Arquitecto can be contacted here:
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Re: Test lighting

Post Wed Jul 04, 2012 10:59 am

@Condar
Very nice Method ! I didn't know about the Focus Blur Filter in Gimp :-)

I did a little test with Cycles (Postproductions with the Blender Compositor).
I know it's still noisy (1000 Samples, GPU, 13 min. Rendertime on a Quadro 5000).

render_01_040712.JPG


Kind regards
Alain
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