Is there a limit to the number of instances on layers that the Generate Stroke effect can be used? I currently am experiencing major rendering/preview issues when having more than 20-25 layers running simultaneously. I have a six-core system with 24GB of ram and a video with 2gb dedicated DDR5 ram, that usually runs flawlessly. I'm currently working on a project with about 500 layers, of which 200 are generated strokes using paths copy and pasted from Illustrator.
There's no finite limit I'm aware of, but 500 layers is an awful lot of calculation, and there's always going to be a real world limit based on the capabilities of your hardware.
Try to work smarter. If possible, pre-render elements. Use proxy renders where possible. Hide layers when not required. Turn off OpenGL. Reduce preview resolution and turn off motion blur while working. If any strokes are not being animated, pre-produce them in Illustrator or Photoshop so that AE doesn't have to do the work. Consider using Shape layers with repeaters if they will do the job of multiple layers.
As the others said, it's a simple math problem depending on teh compelxity of the shapes and specific settings used. You could perhaps get more and better performance by doing them as shape layers since those routines are much more optimized, but even then there will be a wall somewhere along the way...
Thank you for the insights and ideas, they are very much appreciated. While I am working with many layers, I should point out that they are not all on at the same time throughout the timeline. Each animated stroke is completely unique. I definitely have OpenGL off and my preview resolution is often at a custom level below quarter. Here are more details if you're interested, but again, I really appreciate the input.
I am working on animating a illustrated map that is an 8000x8000 png. I have probably 250-300 layers of the map with various animated masks, moving camera, feathering, modes, roughen edges and opacity to simulate ink bleeds. While this sounds heavy, the 2 minute clip usually took about 4 hours to render at 960x540. The previewing at either half or quarter resolution was maybe a second or two to load. As soon as I added the animated lines using the paths from illustrator, render time shot up to 25-30 hours estimated and climbing. These lines are not incredibly complicated, using 15-30 points at the most. I found that 15-20 simultaneous instances of layers with the Stroke Effect on didn't change preview or render time at all, but as soon as the number inched above 20, everything took a nose dive. 10 minutes just to preview a single frame at half resolution, retiling of my open windows and palettes, white screen flashes. If I dialed it back to 20 or less, back to normal! So, I decided I would precomp just the lines, same story. Ended up doing two passes with every other layer turned off each time, and the render time was about 6 minutes for the two minute clip at 1920x1080. If I tried to render just the Stroke Effect layers allowing up to 30-32 simultaneously, the same problems would return, even without the additional ink bleed layers. For some reason, this just felt like a really hard and unexpected wall to come up against, especially given the relatively minor additions of the lines compared to the overall complexity of the project, as well as the continued problems even when isolated.
Thanks for taking the time!
Mmh, sounds frustrating indeed. Though I never have observed this behavior myself, this could be soem sort of odd bug in the effect itself. Perhaps you should report it with as many details as possible and include a pointer to this forum thread...