Texture Streaming Problem

I’m having an issue whereby textures on some new static meshes I’ve imported are streaming in/out very aggressively and noticeably.

Here is a video showing this: UDK Texture Streaming Problem - YouTube

It doesn’t seem to be happening (at least not noticeably) on other meshes in my game. Note: I have disabled LOD transitions on the trees in that video, so it is not being caused by that.

It is particularly noticeable and distracting on the leaves on the trees which use masked transparency, as the shadows fade in and out as the textures stream.

What is even more confusing is sometimes (after playing around in the editor, saving packages etc) it will stop doing it. But then the following day will start again. Making it very difficult to troubleshoot. Also, this issue doens’t happen when i’m in the editor.

Does anyone know how to fix this? I’m hoping perhaps @Chosker might have some ideas?

In ColdGameEngine.ini, if you change these values:

LightmapStreamingFactor=0.16
ShadowmapStreamingFactor=0.16
MaxLightmapRadius=8000.0

Does that help?

Same problem here.

Hmmm I dont see anything obvious except maybe having too much texture memory used.
Lets see
Can you show some stats with stat commands related to textures?
Are you using texturegroups? If so is there any difference in texturegroups for the offending textures?
They are power of 2 with mips, right?
Does it happen if you put the trees on an empty scene?

Hi @Chosker

I have tried playing with the various texture groups. None seems to make any difference.

I have discovered that this streaming glitch will not occur after freshly importing a texture (or making a new copy of the existing texture).

But then whenever I save a map that uses a material with this texture, it will become glitchy.

I’ve made this quick video showing this: Texture streaming glitch - YouTube

The only way currently I can fix this is by copying the texture and switching all materials to use the newly copied one. Which obviously is not a scalable solution.

Any ideas?


Update: I just tested this on a totally clean install of UDK-2015-01 and the problem is still there (with only importing that tree mesh and one texture file).

This glitch also does not occur if you run the game from the editor.

huh, weird

does it happen because of the texture, the material that uses it, or the mesh?
can you use the texture on a cube with a new material and see if it happens?
then with your material on a cube
then with a new material, on your mesh

Yes, perhaps it is related to the mesh, not sure. I will have to test this at a later date.

For now I’ve gotten around this by dynamically switching the opacity texture at runtime with one that isn’t used anywhere on the map. This fully solves the problem, although is obviously very hacky.