The first feature I tested in UE4 is the dynamic lighting, as that was the weakest point of UE3 for me.
I was glad to see that the white lines following the player arround have gone for good. However this wasn’t the case for the shadow acne. With a standart directional ligth moveable and a landscape the shadows still look like this:
I turned OFF the bUsePrecomputedShadows setting in UE3 on static meshes to drastically reduce the shadow acne which makes them looks like this:
However this option doesn’t seem to be exposed/available for static meshes in UE4, or at least I couldn’t find it in the lighting section shown below. So are we stuck with shadows that look like that for big static meshes?!?
I tried reducing the Self Shadowing Accuracy parameter, but this only helped against the shadow acne on the landscape, not on the static mesh. Even for those I had to set the accuracy to about 0.1 to get the shadow acne down to an acceptable level.
So my question is what settings are recommended for the DDL Moveable (the sun) for an open world landscape with fully dynamic lighting? Are there any other settings that can be changed to improve the dynamic shadow quality?
So far all I’ve done is the aforementioned settings plus turning on Force No Precomputed Lighting in the world properties.
We will make improvements to the shadowsin the near future. You can try a new experimental method with
r.shadow.method 1
which fades between cascades and does some other things in a more efficient way (distance in z, not radial, better culling performance).
Actual content can hide the issues with texture variation and more high poly meshes.
Have you tried adding additional whole scene shadow cascades and/or tried decreasing the whole scene dynamic shadow radius?
I tried adding more cascades and that made the shadow acne subjectively appear worse. This is the case because there are extremely ugly transitions between big “acne” lines and smaller ones. Objectively the acne improve some with more cascades, but the horrible transitions negate that possitive effect. Decreasing the shadow radius only makes the situation worse, as the transitions happen closer together then, which makes them even more obvious. However it doesn’t seem to have a positive impact on the acne anyway.
I kept experimenting with the settings in the meantime and these are the best I could get:
That pretty much eliminates the shadow acne, but it revealed another flaw in the system which I would call the “spotlight”. A white circle constantly follows the camera/player arround. With low shadow accuracy it isn’t very visible especially in the editor. However in-game it is very obvious:
So either the dynamic lighting implementation of UE4 is quite old&crappy in comparison to its competitors, or I am missing some setting/code change that has to be done to fix these issues. If it is the latter please let me know what the recommended settings are, and if possible make them the default.
I love the new features of UE4, but the old CSM shadows really dragg the whole thing down.
So I’m getting this type of look using a dynamic spot light with shadows on. When casting on a very large object in my scene I get this weird shadow acne/model faceting type of look. It isn’t as bad as some of the screen shots above but you can see every polygon in the model, it makes it feel as if the model has hard edges all throughout the model.
Was there any word on if this is fixed or not? If not when will this be addressed?
Hey NickZucc -
Can you post this as a new question for us to track? This is an archive post from our Engine Beta process and most information is obsolete in the current iteration of the engine. Let us know exactly what version of the engine you are using and any additional details as you are experiencing them and we will start looking into this for you.
Thank You
Eric Ketchum
