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Smoke bake: A/V sync breaks simulation baking
Open, Confirmed, MediumPublic


Operating system: Win7 x64

Second bake-cache stucks, plays random pieces of baked animation, even if file is saved.
Free scrolling through second bake also working only after reloading file.

Minor Bake-UI flaw: new cache should prompt to bake current quantity of frames: 1—80 in the video, not 1-250 every time, ignoring setted length.

Blender Version

2.8 15/02/2019

In 2.79b rarely stuck if file saved and random frame picked. Instantly switches between bakes on the flow (2nd video).



Event Timeline

Sebastian Parborg (zeddb) triaged this task as Needs Information from User priority.

I can't reproduce this on my end. Does this still happen for you with the latest blender beta?

It is strange. Sometimes it work pretty stable and nice without reload.
Sometimes glitchy.
Once 3rd bake killed 2nd bake despite I saved file after each one. Here I catched 1rst frame killed. Sometimes 1-3 frames of previous bake are missed.
Anyway now Blender reacts for switching between bakes.

May it depend on HDD speed? Or bake goes into RAM at first?

Which beta build are you currently on?

Usually I use fresh one. ATM 2.80 (sub 45), 893fa598319e, 2019-02-24 22:02
Bug still here. After reloading file I have normal 1st bake and broken 2 and 3.

I found that problem is only for big domain and large cache. So try to upscale domain with slowest hdd you have.
It feels like smoke baking system just run faster than HDD-recording and skips frames in baking and loading.

Just tested fresh 2.79b with similar domain size, fast smoke. Works fine even with high compressed cache and slow hdd.

Had similar weird behavior with regular animation when AV sync is enabled. Try disabling it and see if that affects on anything.

Yup, it works good, if baked without AV-sync.
But AV-sync playback works good with this proper bake.

So, my guess is that AV-sync has some effect on the backing, even though it shouldn't. At least, i don't see a reason why it is affected by sync option.

May be something indirect: AV-sync affects to playing frames, frames switching during baking, so pace of frame switching affects baking somehow…
As I said, sometimes it looks like skipped frames and interrupted simulation.

@Sergey Sharybin (sergey) unless something changed since I last tried, this is also a problem with the cloth sim. If you have AV-sync on, it will skip frames and the simulation will not run correctly.

Can i help anything else?
I see status, that info required. What kind of info do you need?

Sebastian Parborg (zeddb) renamed this task from Smoke bake: second cache not showing properly until reloading file. to Smoke bake: A/V sync breaks simulation baking.Mar 1 2019, 11:19 AM
Sebastian Parborg (zeddb) raised the priority of this task from Needs Information from User to Confirmed, Medium.