Texture jitter strangeness

[Tore]

Heeeeeelp!!! What's happening here? The (tiled) decals on the building in the background of this shot jumps and jitters when rendered!!

 

Anybody experienced anything similar, and maybe even have a remedy?

 

 

[jimd]

Heeeeeelp!!! What's happening here? The (tiled) decals on the building in the background of this shot jumps and jitters when rendered!!

 

Anybody experienced anything similar, and maybe even have a remedy?

 

 

 

yes i had a similar problem

in my case it was a bad patch and normals were not facing out

and i was unaware of any of this until i did a camera move like you are doing

and then the decal started to pop

 

 

bty

love this look

[pixelplucker]

Looks like co-planer faces.

Are there double patches on the background model?

[Tore]

Hmmm...no double patches (tried to rebuild the model from scratch). And nothing wrong with the normals. The jitter appears on other models too, under certain circumstances.

As far as I can see it has something to do with tiling the texture/decal, but I cannot find any consistency in when it happens. :-(

Thanks for the replies though :-)

[pixelplucker]

Can you post a prj that has it? I can see if it does it here.

[Tore]

Here is a simplified version of the scene. Thanks for trying to solve this :-)

 

 

[pixelplucker]

I looked at the stamp and the uv's looked a little odd where you used a cylindrical map on a cube. There was a straggly spline where the seam would be.

I made a new box and used bitmap plus instead of a stamp which is procedral. Tossed the normals facing inward so try a test render on that.

 

You can change the repeat of the texture in the material options menu.

 

Not quite sure why the uv came out weird maybe an order thing or maybe because of the shape and map type combo, hope this works.

texjit2.zip

[Tore]

Excellent!! That did the job! Have just re-rendered the sequence, and the texture stays on rock steady!

Thanks a lot, Ken :-)

[pixelplucker]

Ahh good, glad to help, sometimes it takes an extra set of eyes to see something.

[robcat2075]

Yay! Problem solved. That was a strange one.

[Tore]

Playing a bit around with the scene file, I was surprised to find that the jittering consisted even when removing the decals all together.

 

Apparently this has nothing at all to do with texturing, but is some problem with the splines in combination with certain camera angles/movements.

 

Anybody experienced similar problems? Propably should report this as a bug?

 

 

[NancyGormezano]

I suspect this is a matter of computational resolution error.

 

Perhaps it's the combination of klieg light computation, in combination with peculiar/odd angles for both camera & klieg, as well as having a particularly long box with long faces.

 

I shortened the box length/height and the jitter goes away, on my computer. (17g-32PC).

 

Or perhaps you can add faces to the box along the length, so that the computation might work better? I did not try this.

 

Perhaps you can work around this?

ShorterHoejhusspline_jitter_report.prj

[robcat2075]

I propose another cause. There seem to be two splines occupying the same space.

 

Go around that block and click on a long spline (which will select a CP) the hit comma to select the whole spline loop. Do that on several long splines and you will find that two spline loops seem to either share the same spline segment on a long corner.

 

That's not normal.

 

Actually it's not normal for a 4-CP loop to close with a patch at all.

 

Some odd modeling work-flow is possibly in play here.

[Tore]

Surely there is something odd going on with the splines in the old model. So i made a new one from scratch, checked all splines and individually decaled each face. The result was the same: Jumps and jitters!!

I then subdivided the old model as per Nancys advice, and this seems to solve the issue, and works just as good as using the bitmap plus solution.

So now I have two workarounds, but still: is this a bug that should be reported, or just "one of those things"...?

[pixelplucker]

If you look at the stamp of the original model there was a spline that connected from top right of one seem down to the bottom left of the other side of the seem rather than just a clean seem with no connecting spline. I suppose it would be easy to just split that cp out but you might lose part of the uv causing a blank spot.

 

Not sure if that model was originally built in another program and imported.

If I do a cylindrical map on a model built in AM even just a cube the seem is fine.