Fracture - refraction artifacts

[rende]

Hey, hope someone can help on this one. Been searching around and couldn't find a solution.

What im doing: Bring in a closed OBJ bottle, fracture it with time scale set low to get slow motion.

Write out a obj sequence that I read into Modo to render. I know.. pretty weird pipeline, but its for fun

Now... im pretty happy with how it looks still, but as soon as you check the animation you see alot of flickering artifacts.

I believe its intersection issues? This is a pretty common thing to try and do, so someone must have ran into this. Otherwise I'll just continue testing different things to fix it.

Animation (short, but shows the problem): glasstestNuke.mp4 1.5MB

[johner]

Have you tried doing a test render in Mantra? Just wondering if it's Modo related or actually something about the geometry.

The fracture transition looks pretty smooth, so you're probably already doing this, but for slow motion fractures I would set the Substeps parameter on the Dopnet pretty high, like at least 3 or 4. That might help with any interpenetration as well.

Here's some old glass fracture renders I did as a test. They're really testing the dynamic fracturing more than the rendering (as you can tell from quality of the renders , but they show very little flickering, so what you're trying certainly should be possible, at least if staying within Mantra. These are PBR renders:

https://s3.amazonaws.com/vfx/bottle_break_env.mp4

https://s3.amazonaws.com/vfx/bottle_break_multi_env.mp4

[rende]

Hi, thanks for the reply! I don't know mantra well enough to get decent results with reasonable render times, well not something where I could see if the problem is the simulation or not.

I pushed up the substeps to 8, triangulated and made sure the normals are correct. So will report back if that solved it.

Your glass fractures are way too fast to judge if you had the same issue or not unfortunately. Cool though