Flickering Distance Fields (and DF shadows)
I think this is the same bug like here: https://answers.unrealengine.com/questions/314077/flickering-distance-field-shadows-on-ati-video-car.html
I also see flickering distance fields. I use the AMD 15.11 driver, so the old bug should be fixed. This is what I see:
It only seems to happen on ISMCs though, and it gets worse the further the camera is away from the mesh. In that gif you see a bunch of stones, just one ISMC with a few hundreds instances. And since the distance field has extreme flickering, you can imagine how the shadows look like :)
Hi John, I'm helping Eric with this one.
There are limitations with Distance Fields features in a small area. This is culling that is done based on some hard-coded limitations, which is not a bug.
This hard-coded value is controlled by MAX_OBJECTS_PER_TILE and this max is necessary because of D3D11 limitations. It's culling per tile. You can work around this by disabling small meshes, like grass. This can quickly cause this issue to become apparent in your scene.
Some CVars to be aware of.
r.DFShadowScatterTileCulling: This is on by default, but will disable tile culling which can sometimes work to get rid of the shadows poping in and out however, this is still under the limitations set by D3D11.
r. DFShadowWorldTileSize: This is set to 200 by default, but increasing/decreasing the tile size can help in some situations, especially with some larger objects. Inputting large values will not likely help in this situation though, again, the number of objects per tile is still limited by D3D11.
Hopefully things can be improved in the future. Just to clarify as well this is not related to the AMD bug that was reported with Distance Fields not working. That has already been resolved with Catalyst 15.10 and the latest AMD driver is 15.7.
answered Feb 18 '16 at 01:19 PM
Tim Hobson ♦♦ STAFF
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