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7.5 lighting calibration
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7.5 lighting calibration // New Users
Post by weaveribm // May 13, 2007, 1:45pm
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weaveribm
Total Posts: 592
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I'm trying to creep up on good lighting settings but it's all a bit new and puzzling so I've grabbed a couple of troublesome renders alongside the Vray settings, perhaps someone can spot where my focus should be to get rid of the Psychedelic render and the Posterised render please?
The posterised/posterized render is using the Light Map settings which I have no clue at all about but they look interesting
I notice that the inflight and the area light (both outside the window) have strange shapes in the Workspace window, which I think are like the function that makes a cube look like a blowfish...
Wonderful now in workspace preview - apart from the lighting in which everything looks floodlit (small room, third image) - fairly whizzing around and no need to hide groups of objects (as I do in the Modelling window) to speed up the display. Mind you I couldn't do that if I wanted to which is lucky :)
Thanks in advance for any help!
Peter
Trippy man
http://i117.photobucket.com/albums/o63/Mington/7.jpg
Very high contrast
http://i117.photobucket.com/albums/o63/Mington/7-1.jpg
How it used to look in 7.11 :)
http://i117.photobucket.com/albums/o63/Mington/lowishbouncing_nowarealightsfixed7.jpg |
Post by Jack Edwards // May 13, 2007, 2:33pm
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Jack Edwards
Total Posts: 4062
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For starters i'd set the Primary GI to Irradiance. Also Lightmap for second bounce gives you more light inside the room from the way it calculates bounces. How many lights do you have in the scene? They may be set too bright.
You could also try lowering your first and second bounces back to the default of 1.0
-Jack. |
Post by Heidi // May 13, 2007, 3:15pm
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Heidi
Total Posts: 335
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I agree with Ed that your first bounce should be irradiance. But your area light looks like it's waaaaay too hot. :)
Double-click on the color of your area light and try Hue:160, Sa:0, Lum:46.
See whether that gets you closer to what you're looking for. |
Post by parva // May 13, 2007, 10:34pm
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parva
Total Posts: 822
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Jack is right.
Don't use Lightmap as first bounce GI only as second. tS vray don't support bidirectional pathtracing (where it would work as first bounce).
And as said Lightmap tends to bring more bounce light into your scene as direct computation. It creates smoother results but does also stronger color bleeding.
Another minor tip: Don't overbright your scene, means use lights with less intensity and material colors with less then 255 rgb (180 like default is a good value). Scenes with overbright material or bright reflections need longer to render as scenes which are darker. You can brighten up the scenes later in a picture program like CS2 (there unfortunatly tS has no exposure control yet). |
Post by weaveribm // May 13, 2007, 10:36pm
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weaveribm
Total Posts: 592
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Thanks both!
This is after setting the area light from zero to high values, changing the intensity/luminance little by little. Things were very dark and then became very bright.
I started out with the settings that were loaded as part of the scene from 7.11, irradiance and so on- then I remembered you mentioning Light Maps for indoors Jack. That looks very nice in the building of the er, shadows now thinking about it
Everything reset then to defaults next time and stepping up from low luminance to high luminance. I'll start from no lights and step it up in smaller increments thanks for your help. And printing out the relevant manual bits now I'm at work who said that :)
Peter |
Post by weaveribm // May 13, 2007, 10:43pm
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weaveribm
Total Posts: 592
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Don't use Lightmap as first bounce... tS vray don't support bidirectional pathtracing (where it would work as first bounce)
Very interesting Parva, thanks!
Peter |
Post by parva // May 13, 2007, 11:54pm
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parva
Total Posts: 822
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I must correct me :D
You can use Lightcache as first bounce (even if I see no reason for that). I wonder just about the splotches you got in the first picture. These shouldn't appear on final render.
And it should call progressive not bidirectional (but that's another story :D)
sorry again for the false information. |
Post by weaveribm // May 14, 2007, 1:20am
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weaveribm
Total Posts: 592
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I wonder... about the splotches
Me too Parva :)
Not to worry and thanks for that info Parva, I will make small lighting changes and find out what is happening. I can still use 7.11 while I am experimenting in 7.5 - and I enjoy the finding out too :)
Peter |
Post by Jack Edwards // May 14, 2007, 5:15am
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Jack Edwards
Total Posts: 4062
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yup my fault, I should have mentioned that when I mentioned Lightmaps for indoor I meant on the second bounce. ;)
I notice you mentioned luminance. Make sure you set your materials' luminance to zero -- otherwise they emit light... that might make those splotches you are seeing.
-Jack. |
Post by weaveribm // May 14, 2007, 6:24am
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weaveribm
Total Posts: 592
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Thanks Jack.
I've thought of a good way to introduce myself to the LE which I'm interested in - to stay in the workspace where I can. If someone can help please-
I have an area light outside a window and I wish to adjust it from the Workspace
I can see an Area Light object in the LE and I looked it up in the 7.5 manual to find that rather than the parameters talking about brightness the parameters turn this natural way of thinking about light into talking about attenuation - which I understand ok but which appears to add a level of unnecessary complication to what should be a simple list of parameters. 'This bright' rather than 'this attenuated'
I especially fear the Threshold Attenuation parameter which 'specifies the final light intensity that is considered as zero. Any pixel in the area with an attenuation lower than TA is not lit... you can freely mix the coefficients...'
Honestly no wonder we find this stuff tricky :) (I know it's the Chaos Group's software and not Caligari to blame)
Anyway pressing on I tried to link the parameters for the Area light in the light's parameter box (in Model side) to the parameters in the Link Editor's Area light object's (phew) parameters. But I can't see the two sets of parameters lining up: and halving the value of Constant Attenuation '0.5 means double intensity' did not appear to double the brightness of the area light... the scene remains dark
So- how to adjust an area light's brightness from within the Workspace window? That will be helpful please and can I ignore the parameters that lead to 'some pixels not being rendered'? I pay to see all the pixels lit :) I changed the colour of the light to check that I'm working on the right light - there is only one - and no pink light anywhere. Start with a cube in a box with a hole yes I'm thinking about doing that but I wanted simply to press on with the animation (flythrough) but more speedily as 7.5 renders Vray scenes faster than 7.11 doesn't it <runs away> :)
I'm going to use 'brightness' rather than 'luminance' in future Jack, to strip out the jargon if possible - sorry I complicated things and thanks ever so much for helping out. There's no material light emission under Vray I think, I wanted to use that in 7.11 for a radio dial but it only works in Lightworks I think. Sheesh is this stuff complex or what. Smashing I love deep stuff - truly. Real satisfaction on freeing up the gridlock. Eventually. With much help from you guys :)
Peter |
Post by Jack Edwards // May 14, 2007, 6:58am
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Jack Edwards
Total Posts: 4062
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I think I noticed the equivalent of material emission with GI when I set a sky sphere with a luminance value. It might just be that the light bounced was multiplied though... LOL
As far as I know the color value is the brightness. Attenuation affects how far the light travels. Basically it's the speed of decay. Threshold if I'm understanding it correctly is the smallest value of light that DirectX/Vray will bother to calculate for -- but I may have that wrong.
I think Workspace side the light settings are probably more related to DirectX than VRay...
For the settings for the area light, click on the "Panels" tab in the Stack View, then click on your area light. If you have a lot of panels open you may have to scroll down to see it:
5998
Edit: BTW, do we get to see an updated render? :)
-Jack. |
Post by weaveribm // May 14, 2007, 11:32am
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weaveribm
Total Posts: 592
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Attenuation affects how far the light travels
It affects the value of the brightness (or more correctly the luminance again :) reflected from a standard greyscale test card yes in linear or logarithmic numbers
Threshold if I'm understanding it correctly is the smallest value of light that DirectX/Vray will bother to calculate for -- but I may have that wrong
Ah that sounds more like it thanks Jack yes that makes sense thanks, the cut.
Render of course! when sorted, flying online right now (waiting to fly I mean not in the cockpit lol) and someone is asking me for- I'll get back to you :)
Peter |
Post by weaveribm // May 14, 2007, 12:50pm
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weaveribm
Total Posts: 592
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Here's the scene rendered in Vray/GI and in Lightworks (or the default nonVray renderer)
The area light is Intensity 15.41 with linear falloff. Searchlight light values.
The scene is blindingly-lit in both Model and Workspace windows but really dark Vray renders... even at this very bright lighting the scene is very dark in the Vray render. Can anyone see what's going wrong please?
Silly bounce numbers are to try to get some light showing somewhere... no go.
Thanks for any help offered!
Peter
Larger version at 1600x1200 standard res
http://i117.photobucket.com/albums/o63/Mington/calibratingvray1.jpg
http://i117.photobucket.com/albums/o63/Mington/calibratingvray1_800x600.jpg
Vray 7.11 same scene
http://i117.photobucket.com/albums/o63/Mington/lowishbouncing_nowarealightsfixed7.jpg |
Post by weaveribm // May 14, 2007, 12:55pm
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weaveribm
Total Posts: 592
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Btw the glass material is 'LWReflection shader' in Reflectance properties that might be something - and to show that I'm trying to master the LE so I'm willing not lazy :)
I'll take the glass out tomorrow to test I'm getting the call thanks all
Peter |
Post by Jack Edwards // May 14, 2007, 1:01pm
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Jack Edwards
Total Posts: 4062
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The higher the attenuation value the shorter distance the light will travel so try a lower attenuation. Heck for sunlight maybe no attenuation. ;)
Also without caustics and transparent shadows the window blocks the light. In Prodigy's tutorial he took the glass out.
-Jack. |
Post by weaveribm // May 14, 2007, 10:48pm
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weaveribm
Total Posts: 592
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...without caustics and transparent shadows the window blocks the light. In Prodigy's tutorial he took the glass out.
Ahah Jack thanks a million for a very satisfying lightbulb moment over coffee this morning in grey chilly London where the work is. I say "I'm going to work" and she says "No, you're going to where the work is..." :)
Much appreciated is your sticking with this one for me Jack. Roman's right you should be on salary.
Transparent shadows doh!
Yes I toggled off Transparent Shadows right away to allow 7.5 to have its rendering head...
'Who needs transparent shadows they must slow things down surely?' lol - cheers mate
The paint must be peeling off the lightside of the building oops :)
Prodigy's Vray tutorial is a Biblical reference work thanks Prodigy. I should have done the step-by-step sorry Jack. Which I did when I started out it's very good and I follow Prodigy's posts about Vray around like Watson the fox terrier puppy ©
Fiat lux. Let there be Lumens :)
Peter |
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