GI tips

From Realsoft3D Wiki



This article gives tips on GI usage and everything related. Note that this is not a tutorial on GI usage, but a collection of tips & tricks.




  • RayCount1 is for surfaces directly seen by the camera etc.


  • Amount of GI Bounces. Keep the .01 there.

GI Reflection

  • Quick way to control general GI strength


  • Contrast tries to remedy the detail loss caused by the post blur

RayTracer Randomness

  • For proper randomness you might want to set this as high as 10 (or 1000000 if you want)

Post Effect



  • Big kernels are slow as hell and lose detail
  • Use the default or even smaller values
  • If you need to use a big kernel, try to use higher contrast values in the GI material
  • aa_blur can be removed: the image can be blurred in post if necessary

Brightness Control

  • Can often be used in place of higher bounces


  • Drop accuracy to save memory


  • Set scaling to 2 or even higher to make the draft render fast.
  • You can also remove the blurs

Render Setting



  • Keep it off... Antialiased object edges cause interobject color bleeding in the post blurs. This is not the color bleeding we're looking for (or so this robed guy told me).


  • Keep at or above GI Bounces


  • Use as a 'backwards aa' in joint with post image scaling
  • Set it to 4, 4, 40 or something...

Safety Area

  • turn off if you don't use box rendering

Box Rendering

  • use lotsa boxes with displacement


  • Turn off if not used

Geometry Quality

  • Set to low, it renders faster and the visual impact is barely noticeable

Scene Setup

Other Materials

  • Never use pure colors (f.e. 1,0,0 or 1,1,1)
    • Surfaces usually reflect max. 85% of received light
    • The darkest known material reflects 0.045% of received light
  • Use average color instead of texture/procedural for higher recursions
    • surface properties
      • if(Surface:Recursion<1.01)
        • Surface:Color=Texture(foo)
      • if(Surface:Recursion>1.9)
        • Surface:Color=(0.1, 0.2, 0.3)
    • Doesn't look good in scenes with sharp reflections


  • Used to provide soft "global" lighting to the scene
  • Hella big (analytic) sphere
  • Hollow
  • Inverted
  • Color: 0,0,0
  • Use illumination, not color
  • Don't apply the GI material to the dome
  • Blur the texture a bit if the GI is blotchy
  • Avoid HDR images that have bright small spots

Key Light

  • For a balanced lighting setup, use a complement of the sky color as the key light color.

Other Lights

  • Don't use ambient lights...
  • Special lights with GI are slow
    • Use min quality and post shading studio (see realsoft3d/manual/postproc/postshading.html)

Indoor Scenes

  • Use brightness control to strengthen GI
  • Feel free to cheat with fill lights


Glass, Reflections, Volumetrics

  • Major pain in the ass
  • Set RayCount2 & 3 to higher values, lower GI_blur_specular
  • Use GI_specular instead of reflection where possible


  • Don't do it

Customizing the GI material

  • Stripping specular component
  • Non-blurred GI

Baking Lighting

  • Big speedup especially with soft lights


  • Set post scaling to 1 and use motion blur
  • Bake static lights