Camera scaled post import creates incorrect motionblur

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Hi all,

We are having motion blur issues when importing scenes into solaris. Our scenes are saved out as usd from Maya. When imported it all works well however to maintain correct unit scale we scale the scene down by 0.01. This sometimes generates incorrect and exaggerated motionblur in the camera. I can't see why this would be expected behaviour as the relation to the objects in the scene is identical. Has anyone encountered this? And perhaps have a handy solution or advice ready?

We are currently using Houdini 20.0.653

/Many thanks in advance
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camera scaling causing problems during render used to be a common issue in the past (at least in renderers that use camera space) until Mantra Implemented vm_removecamerascale property

I'm not sure if Karma or renderer you are using supports something similar, but if not and if it's really the camera scale causing the issue (since you said only sometimes) you may need to remove it by compensating for camera's full world scale
Tomas Slancik
FX Supervisor
Method Studios, NY
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Yes, USD has reintroduced this nuisance. One easy way in Solaris to remove the scale is to use a parent constraint with the parent set to “/“ and have only scale checked.
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Yeah its odd. Im expecting it to be the transforms being scaled as that is the node Im using. Nothing else. Either way it seems placing a cache node behind the scaling fixes the problem so all good for now i guess.
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I'm experiencing the same problem now but cache doesn't seem to fix it. As soon as I scale down the camera the motion blur goes nuts. Cache lop seems to make the transformations of the camera completely different so not sure if that will work. Anyone had success any other way?
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I spoke too soon. Cache lop might work if I put it after the transform. I misinterpreted what 'behind' meant. Running out a test now.
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I found that the motionblur lop will also fix the problem for us. So no need for the cache lop.
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