[Bug] Flickering cascaded shadows

Development Rendering
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1

Hi,

I meet this bug in the previous build (1808360) and also meeting it in the latest (1904627). The mesh has flickering self shadow and also demonstrate the shadow level of the cascaded shadows on the projected surfaces.

It seems related to the fact I’m very close to an object. Since I use objects based on the UDK scale and not the Rocket scale I need to use a low Near Clip value, maybe it’s related and is what is making the cascaded shadows not working properly ?

I tried with two project created each time with the designed build, in both projects I changed the near clip value to 1.0f.

I have attached medias that show off the problem. This gif is made with the latest build on a laptop with a GTX 460 M (drivers 327.23), the video (available on the dropox ftp under : \FabricePiquet\exedre_shadows_bugs.mp4 ) was made with the previous build on a GTX 660 (drivers 314.22).

The gif show a static mesh designed as “movable” (mobility setting) while the video show a static mesh attached to a skeletal mesh. In both case they have collisions assigned (simple cube shape).

flick_shadows.gif

2

I had issues with flickering shadows with any near clip lower than about 8 as I recall, maybe even 12

and I noticed when I got really close to the object then the flickering would occur

It would be great evidence if you were to :

  1. make a test object much much larger
  2. make sure the near clip is above 12

and let us all know if the issue persists

Rama

3

Changing the Near clip to 12 is not enough to get rid of the problem, but 16 seems okay. Unfortunately I need a near clip very low for my assets. Otherwise I will have to redo a lot of things to avoid this problem.

4

oh yes I understand

but at least we now have more data to present to Epic about the nature of this issue!

:slight_smile:

Rama

5

Thanks for the info, especially the part about the near plane. I added this to our bug database to investigate and find a solution.