利用者:Sebbas/GSoC 2017/Reports/Week 11

提供: wiki
< 利用者:Sebbas‎ | GSoC 2017‎ | Reports
2018年6月29日 (金) 06:23時点におけるYamyam (トーク | 投稿記録)による版 (1版 をインポートしました)
(差分) ← 古い版 | 最新版 (差分) | 新しい版 → (差分)
移動先: 案内検索

Week 11

This week I worked on some of the bugs and on fluid guiding.

What's been done

  • I looked a bit further into the (still unresolved) velocity bug. As Nils pointed out last week, setting velocities in inflow regions explicitly seems to matter. I found this made sense and so I made a test to prove this point: First I added an inflow velocity setup to the Mantaflow script that reproduces the bug [1]. Then I compared the outcome with the old setup that did not use inflow velocities.
Velocity bug in Mantaflow not visible when inflow velocities set
  • My first impression from the previews is that manually setting inflow velocities definitely improves stability. Setups with open domains now look much alike to setups with closed domains (as it should be). I tested a range of inflow velocities and at no time did I encounter scenes where velocities exploded / "behaved unphysically" (as it happens when there are no inflow velocities set explicitly).
Velocity bug in Mantaflow. Domain borders should not influence the simulation (differences should only be visible at borders).
  • So there is a chance that this resolves the issue. For the final verdict though, I'd like to know why setting velocities matters. Right now, I think velocity extrapolation plays a role here too: If no velocities get set in inflow regions, the extrapolation builds up velocities in that region at every step, up to a point where the simulation becomes unstable.
  • There was a problem with thin obstacles. In the levelset generating function thin obstacle meshes and planes were not considered. You'd always have to make obstacles sufficiently thick with respect to domain size to get an obstacle effect. I created a new setup which fixes this by searching for the nearest points on the mesh surface in addition to finding distances to the mesh surface via raycasts (for more see [2]). (rB39eb8fa1a611)
  • For fluid guiding I have nothing new or tangible to show yet. I think I have landed a good setup though. More on that next week.

Next up

  • Continue with last weeks goals (especially particle refactoring and cleanup).
  • No matter what the cost, fluid guiding needs to be finished by next week. (Not trying to sound overly dramatic here. It's just that the week thereafter it's already time to write the documentation).

Questions

  • No

References

  1. https://github.com/sebbas/MantaflowScripts/blob/master/velocity_bug_issue_7.py
  2. https://github.com/sebbas/BlenderMantaflow/issues/8