search

PixarAnimationStudios / OpenUSD

Universal Scene Description
http://www.openusd.org
Other
6.06k stars 1.2k forks source link

bug in the Alembic file format plugin for USD, offsetting translate on import #1244

Closed WallmanMark closed 4 years ago

WallmanMark commented 4 years ago

Hi. I logged this as a bug with sideFX but they have just told me this is a Pixar issue.

When exporting a poly car out of Maya and Blender to Houdini Solaris USD (I have just tested both) the car shifts to the center of the car bounding box when using both reference and stage to bring in the object. Using a sop create with an alembic node inside, works as the car was modelled with its wheels sitting on the ground.

(the car wheels should be on the floor). My Houdini Hip file is an education version, in case you cannot load it I have included a screengrab. carSimpleMerge.zip

Best Mark

Windows 10 Houdini 10.0.460

marktucker commented 4 years ago

To clarify the SideFX position on this, when loading the attached .abc file directly into usdview, the car does not appear in the correct position because the /CAR_GRP primitive is untyped, and therefore has no transform on it. It is the transform on this root /CAR_GRP prim that brings the whole car up to rest on the ground plane.

spiffmon commented 4 years ago

Thanks for clarifying, @marktucker . From our perspective, that's a poorly formed Alembic file - if a node/prim is untyped, we have no idea what schema to apply to it, so we apply none, and therefor xform attributes won't even be converted, I'd imagine.

Before trying to hack the usdAbc reader to accommodate this, it would be nice to get the Maya and Blender perspectives on this. Also, @WallmanMark - if you export the same asset using usdExport, I'm assuming everything works?

WallmanMark commented 4 years ago

Hi I will get the person who made the car to try usd versions as well and get back to you. Best

mark

WallmanMark commented 4 years ago

Hi. I have received the car from the modeller. By making sure the car is in the correct location below the root CAR_GRP everything works. Thanks for your help on this. Best Mark

spiffmon commented 4 years ago

Thanks, Mark - glad it worked out!

On Tue, Jun 16, 2020 at 1:23 AM WallmanMark notifications@github.com wrote:

Closed #1244 https://github.com/PixarAnimationStudios/USD/issues/1244.

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/PixarAnimationStudios/USD/issues/1244#event-3447816937, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABPOU2HZKNAYH3U47F7NCHDRW4TXDANCNFSM4N6IMKCA .

-- --spiffiPhone