I’m currently creating a smoke-screen like particle effect for use with a smoke grenade in a FPS game. Obviously, it makes sense to use lit particle here given that the smoke screen is intended to be quite large and take up a lot of screen-space, and probably draw a fair bit of attention.
However, I’m getting some very strange lighting artifacts, and the lighting appears to be based on the camera view direction rather than its location relative to the sun and the particle system, which isn’t much different than what we could do in Unreal 3. Perhaps my settings need tweaking or I’m going about generating my material the wrong way?
Below is a video of me moving around the world with my particle system in place. The system is set to ‘cast shadows’ and uses a lit material for the large smoke body. Gears of War 3 had a fantastic smoke-screen particle system, that also lit up from the inside with the dynamic lights generated from the muzzle flashes, and was extremely well done. Could any light be shed on how to achieve a similar effect in UE4?
Here is the video:
And here is my current material setup. The Translucency settings we’re originally at default, and I’m struggling to see what difference each one makes. I have also tried TLM_Volumetric, and VolumetricDirectional, neither seem to make a huge amount of difference.
It is related to Translucency Self Shadowing values i believe. How does it look with the default values?
Almost identical, it appears to be making very little difference other than the final colour, which is either incredibly black on one side, or obnoxiously bright on the other side.
My main concern however is the fact that they’re shadowed based on Camera Vector to the core of the particle system, and as such when you rotate, the entire system changes colour, which looks pretty bad.
Okay so I’ve managed to get it looking a little better through some tweaking and a lot of re-compiling shaders.
The strange colours appear to be caused by the ‘back-scattering colour’, which is incredibly sensitive, just the slightest bit of colorised RGB information can have a huge impact on the colouring. The rest of the values I’ve sort of judged by how they look, but I think much more documentation WITH examples is needed on these translucency settings, as at the moment they are somewhat elusive.
Changing the Translucency Directional Lighting Intensity seems to have the most effect, dropping it to 0.4 gave me a much softer shadow and not quite so much contrast. The issue with everything still being from Camera perspective is still a bit annoying though.
I think the reason why shadowing changes when you look at the particles is because the sprites follow the camera and the normals of the sprites affect the lighting. And to get rid of the coloured gradient effect all you need to do is to set the Translucent Multiple Scattering Extinction colour to white(or whatever colour your particles are i think)
Here’s my material setup and what i get with it:
