Few guys asked for setting and i didn't answer anyhting that may help.So I tried to describe what i learned from my short Kray experience. Please note that there are probably better ways to do things, i just don't know them yet
So take it sceptical. Most of tips look obvious and most of it i dig out from this forum. I hope someone will find it useful. There it goes:
I start with setting all materials
Diffuse to 80. This is “base” diffuse value. Back to past when 3D apps hadn’t GI implemented and people were using regular lights and surfacing tricks to mimic real word lighting I was using
Diffuse = 60 as base. Later when LW got useable GI solution I found out that value 80 works best for me. So im using same for Kray, though maybe lower Diffuse values may give you more freedom and possibilities with Kray. I don’t have enough experience to tell that.
Later on Surfacing stage i adjust diffuse values where it needed.
Then, I set Diffuse to 0 for luminous surfaces an set
Luminosity to appropriate values.
Then I add
KrayQuickLWF master plugin , set
Parameter to 2.2 and check
Affect textures. So all image maps and color values will be converted from 2.2 gamma to 1.0 gamma (which is equal to applying 0.45 gamma to images), It will help to keep saturation and contrast of final render.
Next step I put lights to scene. And tune overall lighting. Lighting may change during surfacing phase but I need to have something to start withJ At this point you have to do
Photon Estimate renders to see what’s going on with photons.
Im using area lights for windows and appropriate light types for interior lights (like spots for top lights etc.) Using Area lights for windows instead of luminous surfaces or GI sphere helps to produce better quality shadows. It works for small spaces like apartments and so on, for large spaces like retail areas or casino halls using lots area lights will lead to way longer render times.
There are tips for lights I learned:
Inverse Distance^1 works best for window area lights for many scenes.
You can balance direct/indirect lighting generated by light using
KrayPhotonMultiplier motion modifier. Direct light is controlled by lights Intensity, Falloff distance and indirect light controlled by
Photon power multiplier in motion modifier applied to light. This way you can avoid over bright areas near lights while keeping room well lit.
I run into some problems when tuning lighting:
When using
photonmap if you have spot sunlight with
Spotlight to area enabled or using area light as sun - lights are losing photons. On
Photons Estimate render it looks like a lot of black spots where surface wasn’t hit by photons. Actually final image may look somewhat ok, but you will see dark splotches in reflections.
There are 2 workarounds I came with.
1. Use spot sunlight and disable
Spotlight to area. This way you have hard shadows from sun source
2. Switch to
lightmap mode.
When using
lightmap you may run into bright spots on render. Sometimes they are seen in reflections only. These are caused by “hot”, over bright surfaces near lightsource.
There are few workarounds I came with.
1. Switch to
photonmap mode. For some reason there’s no such issue, but you will have to deal with dark spots if you using area sun:) , though for scenes with no sun it will work well.
2. Move object away from bright light or move light itself.
3. Change light falloff to
Inverse Distance^1.
For those who doesn’t know how falloff works: If we have light with intensity=100%, falloff distance=1m and falloff type set to Inv. Distance^1 or ^2 - then light intensity on 1m distance from light equals to 100%. For ^2 it falls off in proportion to 1/R^2, and for ^1 – 1/R.
Lets see what intensity will be in 10 cm from light. For Inv. Distance^2 it will be 10000%! For Inv. Distance^1 it will be 1000%. For 1cm distance it will be 1000000% and 10000% respectively.
That’s why changing falloff type helps with this situation.
Now about
Photons tab settings. Im using mostly default settings and adjusting
Global photon number,
N value and
Power only. (and set Caustic photons to 0 of course)
Global photons and
N allow to control number of cells generated by Kray. Number of cells can be seen in render window log (something like ***Building Precomputed KD (XXXXX cells)). For these scenes i have
Global photons: 500.000 – 2.000.000 and
N: 300 – 800 and cells number produced is about 60k – 100k, though it read somewhere on forum that 35k would be enough for such scenes. For
Power i have 0.5 - 0.8.
FG tab settings.
FG Treshold = 0.001,
Min rays: 200-400,
Max Rays: 800 - 1200
Spatial tolerance 0.1-0.03 – lower values help with small details and contact shadows (Areas for windows help to keep this parameter high and as result faster FG calculation)
Some objects can slow down FG calculation dramatically. Curtains for example. For these you can use
KraySurfaceOptions shader. Turn
Control FG rays on and use something like 50, 0,01, 200. Very cool ability.
And some surfacing tips I used
For luminous surfaces behind windows I used
KrayIndirectRays shader with
Limit DR enabled and set to 100% or lower. It helps to crunk luminosity up to get good reflections and prevent surfaces to affect indirect lighting (since window light done by area lights already)
When your render has acceptable level of noise on surfaces with blurred reflection but one of object still appears too noisy, instead of crunking reflection quality settings up and ending up with way longer render time you can use
KraySurfaceOption shader for noisy surfaces. Just enable
Control Reflection blur and put settings you like.
People trying to mimic Fresnel effect by using gradient with
Incidence Angle input. Ususally they use 2 keys, one for 0 degrees and second for 90 dergrees. You can improve it a bit adding third key. Im usually clicking near 90 degree key (dark area for Reflection chanel) and drag it up toward 0 degrees key.
FPrime can come handy for fine tuning.
To reveal small details on some objects, like carving and recessing on doors, moldings, seams between drawers and so on, instead of cranking FG settings up im using
IFW Occlusion node with sample number 10-12, Distance 0.1 and Dither Disabled.
Some textures may look too dark or oversaturated when using
KrayQuickLWF if this happens im using LW’s
Image Editor and adjust
Saturation and
Gamma values for particular texture.
For dark areas you can adjust power of bounced photons with
KrayPhotonMultiplier shader. Say you can put it on dark floor surface and set
Diffuse power multiplier to 2 or 3.
ooo very nice, but please show bigger res.