Mesh Flickering

[ambershee]

Hi guys,

I've got a skeletal mesh, that looks fine in the viewer in the editor, looks fine when placed as a skeletalmeshactor in the game, but flickers between being visible and invisible and does not display correctly when used as a pawn mesh.

Any ideas?

[geodav]

the only thing i can think of is the MIC not being parented properly

[ambershee]

It's not the material - it's the actual mesh.

Thanks anyway!

[KazeoHin]

The only time I've seen that is when the Origin is not centered on the asset and the asset does not use exact occlusion information. But, I don't have as much experience with Skelmeshes and code as others.

[ambershee]

Hmm, I'll pass that on to the artist. The mesh seems to be centered properly, but it could be related.

thanks!

[TychoVII]

Most of the vehicle's geometry is not 100% enclosed. Would that contribute to the issue at all? I really hope not, because that would be a major pain to fix.

[ambershee]

Had a chat with the artist. Could this be the result of not using fully enclosed geometry?

Edit: lol, instaposted.

[ambershee]

Update: Fully enclosed geometry also flickers. I'd really like to have this solved by this weekend.

[KazeoHin]

Is the mesh using a translucent material, and if so, is the sort priority the same as other translucent materials in the scene?

[ambershee]

The mesh uses a simple test material that just include diffuse and normal texture maps. Applying any other material yields the same results; like I said before, it's not the material.

[Solid Snake]

The only time I've noticed this behaviour is if I happen to have VLC or some other video media player playing. I'm not 100% sure why, but if I open VLC to watch something (The Simpsons) while I code and test UDK games ... it seems to occur.

[ambershee]

I doubt it's that - it's only one skeletal mesh, and it's consistent across various machines.

[JohNLA]

Sometimes 3d files just go whacky.
Try beating it into submission. When all else fails export it to some older format like 3DS or OBJ and reimport it into your 3d App.

[Solid Snake]

Could be video card drivers? I'll do some testing on my machine and see if I get the same problems.

[ambershee]

Like I said, it's consistent across multiple machines, and it's just this one mesh. I'll try and get a video shortly.

[Solid Snake]

Haven't been noticing it myself as of late. Perhaps your confuddling the occlusion system?

[ambershee]

We created a simple cube mesh and still get the same results.

Ok, the results of some testing with various mesh, material and physics asset:

Mesh does not flicker when:

• We use the default UDK pawn mesh, material and assign no physics asset.
• We use the Cicada mesh, Cicada material and Cicada physics asset.

Mesh does flicker when:

• We use our mesh, but default pawn material.
• We use default mesh, but our material.
• We use default pawn mesh and material, but assign our physics asset.

[Solid Snake]

I'll see if I can duplicate these issues ambershee.

[ambershee]

Cheers. I'm about to go through every combination of settings and take note of the results.

I'll be checking against every combination of:

Default mesh versus Cicada mesh versus custom mesh
Material versus MaterialInstance versus MaterialInterface
Default material versus Cicada material versus custom material

[ambershee]

Ignoring my previous post, here's the results of the tests I just ran. Without a doubt, it's the mesh itself that is the issue:

			Default Mesh	Cicada Mesh	Custom Mesh
mat Default		Works		Works		Flickers
mInst Default		Works		Works		Flickers
mInt Default		Works		Works		Flickers
mat Cicada		Works		Works		Flickers
mInst Cicada		Works		Works		Flickers
mInt Cicada		Works		Works		Flickers
mat Custom		Works		Works		Flickers
mInst Custom		Works		Works		Flickers
mInt Custom		Works		Works		Flickers

I've attached the package in question containing the mesh.

[ambershee]

Moving to the March build appears to have solved the problem.

Now to sort out three-weeks worth of undone code done by the difference in the codebase xD

[DannRees]

I'm having this problem with the latest edition of the UDK. My skeletalmesh flickers, any advice would be great. It's not a playable character just a skeletalMesh used with matinee for a cutscene.

Thanks

Dann

[ambershee]

Yeah, I've also heard of one other person also having this problem, albeit with a playable character. There does seem to be a genuine issue creeping in somewhere.

[DannRees]

Ooh I think I've solved it. Don't know if it's a combination of things but settings the physics asset seemed to fix it. I also made quite a large non-colliding & no mass collision sphere on the asset. Hope this helps someone

[m3fs]

This happens to me all the time when the root bone of the mesh goes out of the view of the camera. The physics asset should help a lot but won't solve it 100% (at least it didn't in my case)

Dan Reese, I put a fix for this on my site somewhere. You can parent the root to the mesh. so it never leaves site of the cam.

[Ghoul]

i had the same problem but i used a false phys asset for a mesh...
changed it and it works...

[zweihander11]

I still have the problem even after making a physucs asset. If this is indeed a no solution problem, does anyone have any guideline in order to prevent it? Like how to model or export a character efficiently.
Thanks anyway!

[deadly161]

Fix:

Ooh I think I've solved it. Don't know if it's a combination of things but settings the physics asset seemed to fix it. I also made quite a large non-colliding & no mass collision sphere on the asset. Hope this helps someone

Issue:

This happens to me all the time when the root bone of the mesh goes out of the view of the camera. The physics asset should help a lot but won't solve it 100% (at least it didn't in my case)

This issue is resolved by applying a physic's asset to the Skeleton Mesh. Then edit the Physic's asset in UnrealPhat and make a new body in the middle of your mesh. Select the new body and check 'No Collision' and scale the body till it is two times the size of your mesh or the end result of the animation.

My mesh happened to be a stream of water which ran down a spiraling canal using morphs, so the body i ended up with was approximately 10x the size of the original mesh and 2x the size of the end morph.

It would seem this bug happens when the bodies of a Skeletal Mesh are out of sight of the controlling camera.

I am using the 01-2012 build of UDK