Environment Probes Documentation

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Even though we use SVOTI for environment lighting, we still need to use environment probes for specular shading. However since medieval times weren't very shiny, we can get by with minimum of those. This article tries to describe where to use them and how to set them up.

Types of probes

We use these types of probes:

  • Global probe
  • Local probe
  • Interior probe

They're all the same entity, but where and how you place them is different.

Global probe

This is a unique probe that influences the whole level except the places where it's overridden by local one. It should be placed in a fairly open and generic spot with size covering whole level. This place should be the most average spot on the map surrounding-wise. In Rataje it is an opened meadow between Samopse and Mrchojedy. Most of the map can be lit only by this. SVOTI can darken or lighten the specular contribution of the the probe based on cone tracing so even with just one probe you'll get many different specular values around the level.

Local probe

This one should be used in places where the surrounding differs a lot from that of the global probe. Typical example is a forest or some deep valley. You should still try to make it as big as possible, i.e. use as little local probes as possible to cover certain area. 

Interior probe

Interior probe should fill all the closed interiors. Make sure it's not affecting outer sides of houses and such. Also set GIBiasMultiplier to 0.1. This affects base brightness of voxels for GI and should help to make the interiors more believable.

Local probes should have priority over global probe, that's why probes have their priorities: global probe 0, local probes 1-19, interior probes 20-255

Environmental probe properties

To create probe, click to Misc -> EnvironmentProbe.

Bellow you can see description of some of the properties as well as recommended/mandatory values for some of them.

  • BoxSize X, Y, Z – dimension of probe
  • GenOffsetX, Y, Z – by default, probe generation comes from its very center. Sometimes it could be useful to move generation center away from probe center; this is how to do it
  • AttenuationFalloffMax - how fast the probe light attenuates when coming close to the border, the smaller the number, the sharper the transition. Transition should be soft for forest probe and sharp for houses (transition area should idealy fit into the walls)
  • fGiBiasMultiplier=0.1
  • Dynamic - has to be checked, otherwise it will not cooperate with Time of Day
  • Sort priority - bigger the number, higher the priority
  • ViewDistRatio - small number, 1 for huge local probes (forest), 5 max for interior probes

How to bake environmental probe

The very new probe has to be baked two times:

First bake:

  1. Open ToD and change weather preset to cloudy_frequent_showers. Rebuild clouds (wh_env_rebuildClouds).
  2. Turn off Total Illumination (Environment -> Total Illumination -> Active off
  3. Turn off probes (r_LightProbe=0 or Probe button on Lighting tool panel)
  4. Select probe you want to bake and click Generate Cubemap

Second bake:

  1. Turn back on Total Illumination
  2. Turn back on probes
  3. Generate Cubemap again

Now turn on Active for the Probe and check the result.

Generated cubemaps

Generated cubemap textures are located in data\textures\cubemaps\LEVEL_NAME\PROBE_NAME\

There should be 10 textures for different times of day. Don't forget to submit them.