Time of Day Material Function

For most ‘Physical VFX’ (Smoke, Water, Blood, etc.) materials in Atlas, we want to rely on the standard UE4 lighting functions but for Non-Physical Emissive VFX Materials (like Magic, Fire, etc.) it can be a challenge to make the object ‘fit into’ the environment properly throughout different lighting conditions that happen throughout the day without blowing out super bright at night or being too dim during the day.

To handle this, we have the ATLAS-TimeOfDayMult function (this has replaced the ARK-TimeOfDayMult and ARK-EyeAdaptationCorrection Functions). To use this function in your Material, you just feed your Emissive Color into the input and feed the ‘Result’ output into the Material’s “Emissive Color”:


To use it properly, you should create a Material Instance (MIC) that you point to this Material and the MIC is what is used as the Material. This exposes these parameters that help tune the result during the Day and Night:


Tune the ‘Intensity’ values to tweak overall ‘brightness’ of the object during the Day and Night and tune the ‘Saturation’ values to tweak how much of the Sun Color will tint your effect (often this will be 0).


As always, please test in a level (like VFXOceanTest) that has proper Lighting and Light Matinee set up to make sure everything works properly under all day/night lighting conditions before checking in. You test the various times of day lighting by scrolling through the various times in the Matinee_MasterDayCycle Matinee. You can also test this by playing the game and setting the cheat code like this to various times of day using Military Time (ex: 1:00- 24:00) : cheat settimeofday 12:00