Modulated Mobile Shadows don't work at all

Development Rendering
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1

I’ve followed the limited documentation 1:1, but I don’t see any shadows at all in the editor with mobile preview. I have Mobile HDR enabled - what can I do to troubleshoot this?

2

i think modulated shadows don’t work in editor did you try to deploy and test on mobile?P.s sometimes unbuilt lightings affects shadow calculations.

3

I tried running as a standalone process with Metal API emulation, but that’s not changing anything. I haven’t tried if they show up in a compiled .ipa running on an actual phone. The documentation has pictures of it working in-editor which would be helpful as designing lighting would be… bad if you can only see the result after an hour of compiling.

4

Same here. Any news on it?

5

Closest to progress I’ve found is finding a vague mention that modulated shadows only cast shadows for skeletal meshes. I’ve since then switched to using a rendertarget for shadows because I just couldn’t get this to work.

6

It’s… exteremly botchy and I’m sure there’s a better way but it works for me. I have an orthagonal RenderTarget at a desired angle. It only renders Actors in a whitelist. Everything I want to read the RenderTarget has either a second UV map which corresponds 1:1 or is using projected coordinates. If there’s something in the render target, that’s a shadow, and my material can use than information however I want to. Runs smoothly on mobile, but if you want extra optimisation, disable render every frame, and manually capture render target every two frames - who’s going to notice? I went an extra step and turn all materials to simple scalar 1, then back after it’s done. My entire scene suffers maybe 0,5 ms from dynamic shadows running on an actual iPhone, but the extra uv math can impact negatively.

7

Thanks, it’s quite interesting! I will try to get the stationary light working but will fallback to your approach otherwise.

8

I see. Thank you for replying. I tried a lot of different things, what I would like to avoid is having dynamic directional light, but I would like to have shadows there. Could you expand on the rendertarget approach or point me to a resource where explains it a bit?
Thanks

9

It implied a lot of trial and error but got it working with the following settings:

Directional light settings:

  • Stationary directional light
  • Modulated shadow turner on
  • Dynamic Shadow Distance StationaryLight at maximum.
  • Make sure the lightmap are always computed (there is an option for disabling the precomputation in the WorldSettings)

Skeletal Mesh settings:

  • Cast Shadow On

  • Capsule Direct Shadow On (no need for physical asset)

  • Dynamic Shadow On

  • Receive CSM Shadows On

I also tweaked some rendering settings but that should be it.

10

I haven’t managed to get it working after a week, there might be some other parts that don’t play quite well with my project. I’m still going to mark this as an answer so maybe it would help other people, thank you! :- )