Skybox and Lights setup
Elements contributing to day / night cycle
- DirectionalLight, actor in the Persistent Level (Yliakum). Casting light globally in a certain direction.
- Intensity
- Light Color
- SkyLight, actor in the Persistent Level. Stores the color of the skybox and influence all items in the game with indirect light based on the skybox color.
- Intensity
- bp_sky, actor in the Persistent Level, which contains all the logic for rain/snow/fog/... , clouds, time of the day, the actual skybox which is a static mesh (dome).
- Light, scalar parameter on the Material applied to the skybox mesh
- ExponentialHeightFog, actor in the Persistent Level, managing the fog. Careful to change its color at night, or the skydome will stay lit.
- Light color
Static vs Dynamic lights
I tried with many different settings and Lightmass is crashing on our hydlaa level very often. Trying to create a minimal set of objects exposing the crash seems not possible, as when you delete some objects may stop crashing, but then deleting more seems to stop crashing, so looks like the combination of meshes, not one particular mesh.
The crash happen with SkyLight and DirectionalLight set as Stationary and also with SkyLight as Stationary and DirectionalLight set as Moveable.
The crash does NOT happen with SkyLight as Moveable and DirectionalLight set as Stationary. So we tried this setting, the problem is the size of the generated BuiltData files.
| Map | Skylight Moveable, Directional Static | Both Moveable |
|---|---|---|
| Hydlaa plaza | 530Mb | 139Mb |
| Gugrontid | 372Mb | 13Mb |
| Ojaveda | 92.5Mb | 53Mb |
| Amdeneir | 744Mb | 38Mb |
Given the sizes above, at the end we decided to keep both SkyLight and DirectionalLight set as Moveable.
up to 0.7.7 release values
At noon:
- Fog Inscattering Color: (R=0.313989,G=0.467784,B=0.887923,A=1.000000)
- Skybox Light: 2.0
- Skylight Intensity: 1.5
- Skylight Color: (R=0.853051,G=0.958179,B=1.000000,A=1.000000)
- DirectionalLight Intensity: 4.965001
At night:
- Fog Inscattering Color: (R=0.023549,G=0.035084,B=0.066594,A=0.075000)
- Skybox Light: 0.15
- Skylight Intensity: 0.1125
- Skylight Color: (R=0.988979,G=0.996863,B=1.000000,A=1.000000)
- DirectionalLight Intensity: 0.3
values from 0.7.8 release
At noon:
- Skybox Light: 1.0
- Skylight Intensity: 1
- DirectionalLight Intensity: 2
At night:
- Fog Inscattering Color: 0
- Skybox Light: 0.04
- Skylight Intensity: 0.07
- DirectionalLight Intensity: 0.07
Rebuild lights - size and timings
| Level | Skylight Moveable | BuiltData size | Skylight Stationary | BuiltData size | Date |
|---|---|---|---|---|---|
| Hydlaa_X08_Y04 | 10 minutes | 132Mb | 39 minutes | 1493 Mb | 19 April 2022 |
| Ojaveda_X11_Y04 | 4 minutes | 43Mb | 6 minutes | 84Mb | 19 April 2022 |
Changes 0.7.19 release
Lights update based on Rycer feedback.
[X] Change the skylight to stationary (was moveable).
[X] Disable Distance field, since they would be no longer needed with static lighting
[X] Keep the landscape lightmap resolution to 1
[NO, it was causing too large lightmaps on hydlaa_level] Trees, go to Foliage mode, and then click on all meshes part of foliage and set Mobility as "static" and change Lighting mode to "Force Volumetric", Keep it as lightmap resolution of 8.
[X] Trees, go to Foliage mode, and then click on all meshes part of foliage and set Mobility as "moveable"
[X] Persistent Level (Yliakum Map file) -> WorldSettings -> Lightmass -> Volumetric Lightmap Details -> 400 (was 200)
[X] Added an Unbound Post Process Volume (PostProcessVolumeWholeGame) with min/max Brightness, min=0.5, max=4
[X] World Settings -> Lightmass -> Num Sky Lighting Bounces to 5 (it was 1)
[X] No Change. Change the static lighting lod to 1 or 2 on landscape only if lightmass crashes
[X] No change. Grass is already dynamic because its placed by the engine
[X] No change. Seems our lightmap resolution is between 32 and 64, overriden by the engine or some of us.
Additional Notes:
5) Because of a low lightmap resolution, make the point lights (torches and similar) a combination of a static and dynamic light. One low brightness, high radius static point light (for bounced lighting) and a second light - bright, dynamic with a short radius
6) Careful use of reflection capture. Ideally one per building, some will require more. It would be useful to change their resolution to 64 or even 32 to save memory.
7) Split some underground areas to new streamed sublevels for less streaming hitches, performance optimization and faster loading.