Running Houdini20.5 I have a usd wheel and tire spinning around 120 deg per frame. The reflection in the chrome material in Karma is smeared. I have tried various mblur settings and nothing seems to help. It is like it calculates the image then blurs it all together. I get the same results in CPU and XPU. It is a simple material with metalness at 1.0 (same as the chrome ball) and reflecting the HDRI
As you can see in the renders the karma render of the USD wheel is smeared, but not in Arnold. However the geo animated in LOPs is reflecting okay rotationally but generating weird inward blurring. If you step through at subsample you can see the alembic goes in and out (usds don't do this) but why does the geo in Houdini get blurry edges
jamesdelf why does the geo in Houdini get blurry edges
I'll cherry-pick this part of the thread to reply to - aware we still need to address the smeared blurring part separately.
The inward blurring here is due to there not being enough subframes to capture the rapid point-based motion. On the Motion Blur LOP you can increase the Subframe Samples to 4 (or even 6) and you'll see a huge improvement in this.
Hi. The smeared reflection issue (not relating to the blurry edges due to lack of motion samples that robp already responded to) has been addressed in 20.5.305.
Yes a motionblur node with 4 does help the middle ring being animated in SOPs. I had one in there but set to 2. The alembic on the right however is not improved and may have to recook that out on substeps 0.1, or stick to USD like the wheel on the left. And now on to IT dept to get the latest houdini down and get some nice unsmeared reflections. Thanks dlee and robp
