View Full Version : Static cache glitches?

09-23-2009, 05:07 PM
Hmm, I static GI cache a simple scene (over multiple frames) and do some F9's or a F10 on the scene.

When I look at the result, I get faint but in animation very noticable glitches of small horizontal lines rendering wrong etc.

Are there some known issues even with basic static cache that I missed?

(only camera moving etc ofc)

edit: I see no such glitches in Classic camera, only in persp camera, whatever settings I try in the camera options.

09-23-2009, 06:10 PM
And also for this issue, switching to single threaded rendering fixes it.. wtf?
But since it is so utterly basic, can anyone please confirm for me?

See attached images and compare in quick succession.

This happens:
-When static cached for multiple frames in an animation with just camera moving.
-Always, with more or less amount. Sometimes it looks ok for a few frames, then comes back full force.

It does *not* happen with:
-Classic Camera
-Single threaded rendering.

:| any help greatly appreciated. I tried changing any setting possible. I'd prefer not reverting to classic cam, it renders alot slower for my scene. Single threaded is not an option either..

I can't believe such a basic option is broken though, so would really like some help in finding the issue.

09-24-2009, 07:56 AM
I've rendered number animations with 9.6 (but 32-bit version mostly) and havn't had such issues. Exept ridiculous long render times with "Animation" enabled. And jumping procedural textures (lasts from version 7.x) when rendering on multiple nodes but seems it isn't your case.
Could you post a sample scene, so i could test it out?

09-24-2009, 09:34 AM
Is that procedural texture?

09-24-2009, 01:53 PM
Nope, it is a high res texture.
Will try to reproduce in a nice and simple scene..

09-24-2009, 04:40 PM
Damn this is a tough nut to crack.
I just can't get it to reproduce reliably.

Also, if you just cache frame 1, lock the cache, and then move the camera to another place on frame 2. Then the result looks really bad. Why doesn't it do preprocessing yet not write the result to the cache?

If I make the cache write only (in Explorer) and then set the Preprocess to "always" I get exactly what I want, without it writing to file. This way, any samples it doesn't have during rendering (for whatever reason, less obvious than moving the camera to a new place) it will at least do a reasonable job at spamming new samples.

See image attached for what locked does, when only a limited region was cached (obviously left upper region) and then the entire shot rendered with locked on. Why?

If you put preprocess on always, it still uses the cached samples but generates a nice new set. I want that, but not have it write to cache.. why doesn't lock do just that?

09-24-2009, 05:27 PM
Daang, I finally found it.
It was the Gradient Backdrop.

So if:
-Gradient backdrop like mine
-Static Cached over multiple frames


See attached scene "GiExample" for an example of this. Just open and render F9 a couple of times. (perhaps do a limited region on the big cube on the left side to keep it quick, lim. reg. should be already active in the scene

I also included the scene:

Just open and F9 and you should see the lack of samples outside of the cached limited region. Why? And what is the sampling based on now?

If I rendered all my frames on a single pc, it would be circumventable by putting it on "always" and make the cache file read only. But I use a renderfarm, which will do "locked" always.. (right??) :(
(I need this for a GI trick to work on the farm too and besides it would make more sense)

ps: yes it is almost a blog here :) But any help greatly appreciated..