motion blur exploding problem

[jstrob]

Hi,


I am trying to render a PhoenixFD liquid and I am getting very long motion blur spiky artefacts. you can see how it looks on these pics:

rendered with vray_adv_31501_max2015_x64 and phoenixFD_adv_22000_max2015_vray_30_x64 (it was originally simulated with phoenix rev 24967).

[jstrob]

well it seems those are caused by small drops going very fast toward the camera... I will have to erase them with a vol. select.

[Ivaylo Katev]

yes, sometimes there are parts that have very big velocity. they actually do not follow it because the internal collisions are stopping them, but in the rendering they cause such spiky artifacts. two weeks ago we added an option to suppress such artifacts, it's a checkbox in the rendering panel called "MB self intersection"
this option activates self intersection test, that clamps the movement up to the contact points and resolves the problem in the most cases.

[jstrob]

ok good to know.

but I tried resimulating that scene with latest nithly (without knowing about this new feature) and the result was too different. there were no drops at the front edge, it seems almost like the front edge was getting compressed.

[Ivaylo Katev]

you mean resimulating with the resimulation feature or just simulate again?

[jstrob]

just simulating it again.

[Ivaylo Katev]

very strange, can you post an image?

[jstrob]

I didn't saved an image and I would have to reainstall the latest nightly to show you. Ii will try to find time maybe this weekend. Now I'm in a complete rush.