Artifact Lines in AFX 6.5 3D Renders

[Kenneth Lustig]

Chris,
I took a look at your theater animation on createdigitalmotion – what workarounds did you use to get that many 3D layers to render properly? In addition to the artifacts (which have gone away for me in 7.0), I’m now experiencing a series of memory errors such as “unable to create shadow map vertices” and frame buffer issues. I’ve tried the secret menu purge trick, reducing the shadow maps to minimum, rendering with a number of codecs and options, exporting, adjusting cache percentages, turning on and off disk cache, and switching renderers. What’s really bugging me is that my render que never shows more than 15% memory use.

[Chris Zwar]

Hi,
As long as you have parallel layers with different Z positions you won’t have any problems. The project you’re referring to – Centrica – was fairly simple, and the layers were always well spaced out and not intersecting. Even when I did have lots of layers (for example the yellow rings were made up of hundreds of 5×5 solids, nothing you can’t do with Digital Anarchy’s 3D assistants) they weren’t overlapping in Z space and so I had no render problems.
The issues (ie. bugs) seem to arise when planes are very close together or overlapping, or intersecting. For example, if you construct a cube out of 6 solids you should have no trouble. But if you then duplicate one of those solids and replace it with a logo so it looks like the logo is on the cube, you’ll start seeing glitches.

I don’t have any suggestions or solutions, just wait for Adobe to improve the renderer…

-Chris

[Kenneth Lustig]

To recap: I built a 3D timeline with approx 7 lights, a couple hundred 3D layers based on Illustrator files, using a camera with depth of field enabled. Basically, I just about maxxed out the limits of the AFX engine. Not having access to the Digital Anarchy plugins, I used just After Effects and Illustrator to create my comp.

I was having huge problems with all kinds of memory issues (not enough memory to create ### X ### frame buffer, not enough memory to create shadow map, not enough memory for blurring, unknown errors, etc). This is on a Windows XP SP2 system with 2GB of RAM, a terrabyte of hard drive space, and dual 512MB video cards which should have had plenty of capability. In fact, the render queue never showed more than 15% memory use prior to a crash.

The problem seems to be related to a memory leak and other assorted bugs in the After Effects rendering engine. In AFX 6.5 the rendering engine produced linear artifacts on my 3D layers once a certain number of layers got added. This was related to the proximity of layers which were close to each other or overlapping. In AFX 7.0 the artifacts went away, but the memory errors were still rampant. In fact, I could get the entire timeline to RAM preview in AFX 6.5 while in 7.0 I could not. The rendering process would not start at all with the 7.0.1 patch applied.

To successfully get the final 3D render, I used a clean 7.0 install. I turned on layer caching in the secret menu accessible by hitting shift before pulling up preferences (note this is contrary to the optimization recommendations in Adobe’s tech sheets). I also set RAM use to 120%/60%, which was also not the recommended setting, but I found that the length of the bit I could render was directly affected by how much RAM or VRAM was available. I turned the disk cache on at 60 GB, which was the largest sized disk cache that seemed to increase the number of frames. I set the RAM preview options to maximum quality – basically, setting them to the same quality as my final render – and turned off OpenGL. Even when I wasn’t using OpenGL I found that the incidence of the frame buffer error was much higher when it was enabled; looking at some related problems in the Adobe tech notes I think there is a video card buffering problem in the code someplace also which might be related to this setting.

To render I moved the mark in and mark out sliders at the top of the composition timeline to shorter and shorter frame lengths. I finally got the RAM preview to successfully complete with the mark in and mark out set to about 120 frames, but the amount is strongly related to the complexity of the scene in the camera’s field of view. Occasionally, I had to shorten the mark in-mark out to as few as 40 frames. Once the RAM preview worked, I saved the RAM preview for my composition. After each RAM preview saved, I quit the program, or else the ratio of frames rendered to crashes accumulated as if I had rendered them all at once. Using the Purging commands between passes and using the purge options in the secret menu did not help – only quiting.

No matter how many frames I had in cache, saving the RAM preview caused AFX to sometimes re-preview cached frames, and it will always inexplicably dump the cache and do a redundant render pass even if layer caching is enabled. However using the export, render queue, and make movie options crashed my renders no matter how short the sequence I tried; only save RAM preview successfully output a file. So, this method is better than having no solution at all. The good news is that such short renders took less than 30 minutes apiece, so if I got a crash it wasn’t a heartbreaking stop after 5 hours of rendering. The down side is that because they’re short renders, I can’t leave the computer rendering overnight so it ties up a workstation during production time.

By holding down the shift key to move the mark in next to the mark out after each save, my clips are rendered out back to back and can easily be recombined in an NLE. I did not do a lot of experimenting with codecs in the RAM preview options, either, finding it alot easier (and probably faster) to squeeze or export the output once reassembled than to wait for a rendering pass to complete.

[Kenneth Lustig]

I neglected to mention – after saving a RAM preview, you need to delete it from your assets list or you’ll run out of memory quite quickly.