I am rendering an old project which used to use redshift with Karma.

I have a simple rbd sim and then transform hires onto the proxies including velocity from the sim.

Karma just messes up the motion blur. Is this a (current) limitation or a bug?

The 4 images are:
no motion blur CPU
no motion blur XPU
with motion blur CPU
with motion blur XPU

lighting looks different, but thats something I can work
the big problem in both is the weird looking motion blur

You can always control the strength of motion blur by adding one line of code to the end of your network. Multiply your velocity down.

it seems to be related to them being packed primitives and also the fact that I am randomly deleting those packed points through the sequence, which leads to point numbers flipping around and karma seems to be confused by that

after i used an unpack node it it worked fine, but way slower of course

also for some reason motion blur on packed just completely fails to render, just wont any more
I guess this may be some bug / graphics driver issue because optix also failed and then crashed


KarmaXPU: device Type:Optix ID:0 has registered a critical error , so will now stop functioning. Future error messages will be suppressed

will test further

It almost looks like the topology might be changing frame to frame. Are you using velocity blur?

mark
It almost looks like the topology might be changing frame to frame. Are you using velocity blur?

I am using velocity blur. But it doesn't work on packed primitives.
Made a quick setup to sandbox the issue.
No matter what I do, Motion blur only works if I unpack the transformed geometry before importing it into solaris/karma world.

chf
I am using velocity blur. But it doesn't work on packed primitives.
Made a quick setup to sandbox the issue.
No matter what I do, Motion blur only works if I unpack the transformed geometry before importing it into solaris/karma world.

Usd expects the velocity primvar to be named velocities. If you stick an Attribute Rename SOP before /obj/karma_test/output0, the instance will pick up velocity properly and you should see motion blur. This is not obvious at all. It took a bit of debugging on my end to actually track this down.

The other thing which I see you attempted was to use "Unpack" in /stage/sopimport1. This uncovered a bug in Karma. This should be fixed in tomorrow's daily build. So leaving the vattribute alone, but choosing Unpack in the SOP import should work in tomorrow's build.

mark
Usd expects the velocity primvar to be named velocities. If you stick an Attribute Rename SOP before /obj/karma_test/output0, the instance will pick up velocity properly and you should see motion blur. This is not obvious at all. It took a bit of debugging on my end to actually track this down.

does it support angular velocities?
since those are important on packed primitives
I tried renaming w to angularVelocities, not sure if that's correct property on regular prims, but also didn't seem to do anything

mark

chf
I am using velocity blur. But it doesn't work on packed primitives.
Made a quick setup to sandbox the issue.
No matter what I do, Motion blur only works if I unpack the transformed geometry before importing it into solaris/karma world.

Usd expects the velocity primvar to be named velocities. If you stick an Attribute Rename SOP before /obj/karma_test/output0, the instance will pick up velocity properly and you should see motion blur. This is not obvious at all. It took a bit of debugging on my end to actually track this down.

The other thing which I see you attempted was to use "Unpack" in /stage/sopimport1. This uncovered a bug in Karma. This should be fixed in tomorrow's daily build. So leaving the vattribute alone, but choosing Unpack in the SOP import should work in tomorrow's build.

that's fantastic thank you so much!