GI tips

From Realsoft3D Wiki

Contents

Introduction

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.

Material

Image:GIBasic.png

RayCount

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

Bounces

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

GI Reflection

  • Quick way to control general GI strength

Contrast

  • 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

Image:GIEffects.png

Blurs

  • 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

Channels

  • Drop accuracy to save memory

Draft

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

Render Setting

Image:GIRendering.png

Antialiasing

  • 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).

Recursions

  • Keep at or above GI Bounces

Undersampling

  • 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

Caustics

  • 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

Skydome

  • 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

Misc

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

Displacement

  • Don't do it

Customizing the GI material

  • Stripping specular component
  • Non-blurred GI

Baking Lighting

  • Big speedup especially with soft lights

Animation

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