I’m new to Unreal Engine, and I’ve recently encountered an issue with shadows on mobile devices in my project. I’m hoping someone here might have some advice or solutions for me!
I’ve attached comparison images showing shadows on PC, Android, and iOS. As you’ll see, the shadow quality on mobile is significantly lower, and the scene appears darker compared to the PC version. After experimenting, I found that increasing the Sky Light intensity by 10 times helps reduce the darkness, but the shadow quality remains an issue.
I am using Forward Rendering, and i have enabled Force No Precomputed Lighting in world settings. Directional Light is set to movable.
Any ideas on how I can improve shadow quality on mobile? I’ve been tweaking settings but haven’t been able to get dynamic shadows looking as good as they should.
you should use the skylight on any mobile forward render. it’s basicly “fake gi” using a static ambient light term to brighten up the shadows.
i have no clue why the shadow resolution and offset is so much different. i guess ios limits the cascade shadow resolution and has lower bit depth for the shadow map depth buffer. the android shadow looks decent. add the skylight and maybe tweak the shadow map bias and you should be good. be aware of shadow acne tho. there are limits to the cascase angles. you’ll not get it to touch the ground at shallow angles, but pretty close.
I do use the SkyLight, as it’s like “fake GI” and a low-cost solution for mobile, so I definitely understand its value. I also played around with the Engine Scalability Settings and discovered that the shadow quality on iOS was set to High, while on Android it was on Epic—which explains the difference in shadow quality between the two platforms. Also in project settings it is set to Mobile and Maximum.
However, I still can’t figure out why the shadow resolution is so low on iOS, and I’m also noticing that I’m losing self-casting shadows, which makes things look unnatural. The best results come when shadows are set to Cinematic—I get self-casting shadows and much better overall quality, but of course, that’s not practical for mobile performance.
Tweaking the shadow bias helped a bit with the ground contact shadow, but the box still seems to be floating slightly.
My scene won’t have too many objects, so I should be able to get some decent-looking shadows on mobile, and I’m not targeting low-end devices—mostly devices like the iPhone 12 and above. Do you have any further suggestions for resolving the self-shadowing issue or improving the overall resolution without going too far into the performance-heavy settings?
self shadowing? iirc… there are some material parameters to control that. not sure right now if a game can be cinematic shadow settings, but only uses self shadows on some actors.
for the basic world rendering self shadows are usually baked for performance on mobile. if your geometry is rather low to medium poly you could try to render the shadows realtime and see how the fps look.
my old dx10 tablet manages a rather dense level (around 20 meshes with a couple materials) with a static self shadowing cascade at around 20 fps. it’s not a metric at all (cause the machine is old and only supports ue 4.26) , but rather saying… “test it how good it runs” on the average user hardware. and then make decisions and optimize.
high quality cutscenes for sure would require self shadows. i can see that being of use. literally cinematics. hmm
Thank you for help. Sure thing, i’ll do the testing. I am not sure if i can get cinematic quality on mobile, probably not, will see. Just thought there might be some settings for increasing shadow resolution a bit because i cannot find it anywhere
Oh, finally found what is it lol i am stupid. CSM setting in directional light, lowering Dynamic Shadow Distance MovableLight which was 40k by default, when lowered to like 1000-2000 this is what i get on High settings for shadows (can even go with Medium), no need for Epic/Cinematic as self shadowing was not visible because of low resolution of the maps.
