Motion Blur of particles w/ instancer wrong

[im.thatoneguy]

If I create a VRay Instancer and point it at a fire sim with particles I get insane motion blur.
If I export a fire sim to PRT and render that, it renders correctly.
I have ID and Velocity channels enabled for the fire sim.

What's the correct workflow to render instanced geo particles from a fire sim?

[im.thatoneguy]

Also as a side note when I export out a PRT sequence I get the same number of particles it seems regardless of the particle rate in the fire source. In viewport I see different particle numbers depending on the sim but in the PRT I always get a very large number of particles.

[slavina.nikolova]

Hey,

Seems to be working here.

Could you tell us which are your exact Phoenix and V-Ray versions? Would it be possible to attach the scene you are working with, so we could check it out?

In order to find out the exact Phoenix version you can check the About info window. 3ds Max/Maya → Top 3ds Max/Maya Phoenix FD Menu → About Phoenix.

You can find the V-Ray version in the Render settings window → Settings tab → About V-Ray rollout.


Thanks!

[im.thatoneguy]

Just as an aside...

[im.thatoneguy]

Oops looks like I'm on a nightly.

4.30.01 Nightly, Build ID: 2021030330635
V-Ray 5.10.02 for x64 from Apr 19 2021

https://sfstudios-my.sharepoint.com/...trAvA?e=H7h5oR

Fortunately/Unfortunately the reduced scene just hard crashes.

EDIT: Just confirmed on latest stable build of Phoenix also crashes.

[im.thatoneguy]

Production scene works in the newest Phoenix! Sorry about the old build bug.

But you're welcome for managing to create a new crashing scene on accident? haha

[Svetlin.Nikolov]

Just as an aside...

Oh yes, this happens if you've had a bad luck to install a certain range of nightly builds. Now a new menu item will be added every time you start 3ds Max, unless you go to 3ds Max -> Customize -> User Interface -> Menus and delete the Phoenix FD menu altogether.

[im.thatoneguy]

The crash is now affecting my production scene too...

[im.thatoneguy]

Also I guess the motion blur problem is still there in the latest build after all.

[slavina.nikolova]

Hey,

Thanks for the scenes! We will check them out and let you know when we have something.

Cheers!

[Svetlin.Nikolov]

Meanwhile, we really DID find something extra:
- If you plug a Simulator in a V-Ray instancer's Particle list and then make sure that all the Simulators and Particle Shaders in the scene are hidden or not-renderable, no matter if they have anything to do with the instancer particles at all, then the instanced geometries are rendered in the wrong position. This will be fixed in tomorrow's Phoenix nightlies.

Will ping you when we know more about your original issues too....

[slavina.nikolova]

Hey,


As for the Motion Blur differences between the Simulator and the PRT Reader.
We couldn't reproduce the problem on our side. I will attach screenshots showing how the results are looking with default MB and with decreased MB.
Could you send us a .prt file, that renders differently?


As for the particles' count in the viewport.
Could you check the Simulator -> Preview rollout and see if the particles' count will equalize, if you decrease the Detail Reduction to 0? More information about the Auto Reduction could be found here - https://docs.chaosgroup.com/display/...Liquid+Preview

Another option that could help you equalizing the particles' count is the Preview limit (K) located in PRT Reader menu. More information about the PRT Reader options could be found here - https://docs.chaosgroup.com/pages/vi...ageId=47534484


Thanks!

[Svetlin.Nikolov]

Hey, got the crash, it's because of this option:



Please don't forget to return it to "Disable" and everything will be okay

[Joelaff]

To control motion blur of particles we export to PRT, user a Krakatoa Loader and then user a magma modifier in krak to control the motion blur length.

Magma Modifier is worth the price of Krakatoa, but Thinkbox has been ignoring all the software except Deadline since being acquired by AWS. Hopefully that will change. I just called them out over it big time.