Loading Alembic in StageView widget in custom Qt interface fails to display Alembic geometry

[BigRoy]

Description of Issue

I'm trying to embed USD view widgets into a custom Qt interface, for which a code example can be found here.

This works fine when displaying the example Kitchen_set.usd scene however when loading an Alembic file this solely displays the bounding box. Nevertheless when using usdview the exact same Alembic file works fine.

Example sphere.abc (zipped): sphere.zip

What am I missing to correctly load the Alembic file? Or am I misinterpreting how to reuse these widgets in a custom interface? What I'm trying to do is have a very simple Hydra viewer to display USD/Alembic assets in our pipeline asset manager. As such a simple Viewport with a timeline (with optionally allowing to enable a hierarchy editor) would be perfect.

Steps to Reproduce

1. Use UI code from my example
2. Set path to the attached sphere.abc
3. Run.

Note how just the bounding box is displayed but no geometry is visible. The following warning can be observed in the Python log:

Warning: in GetPoints at line 552 of D:\dev\usd\USD\pxr\usdImaging\lib\usdImaging\gprimAdapter.cpp -- Points could not be read from prim: </pSphere1>

However, the same file works fine with usdview.

Package Versions

USD tag v19.11

2019-10-30 15:29
curl -s -L -o v1.2.11.zip.tmp https://github.com/madler/zlib/archive/v1.2.11.zip
2019-10-30 15:29
curl -s -L -o boost_1_65_1.tar.gz.tmp https://downloads.sourceforge.net/project/boost/boost/1.65.1/boost_1_65_1.tar.gz
2019-10-30 15:35
curl -s -L -o tbb2017_20170226oss_win.zip.tmp https://github.com/01org/tbb/releases/download/2017_U5/tbb2017_20170226oss_win.zip
2019-10-30 15:35
curl -s -L -o v2.2.0.zip.tmp https://github.com/openexr/openexr/archive/v2.2.0.zip
2019-10-30 15:38
curl -s -L -o glew-2.0.0-win32.zip.tmp https://downloads.sourceforge.net/project/glew/glew/2.0.0/glew-2.0.0-win32.zip
2019-10-30 15:38
curl -s -L -o v3_1_1.zip.tmp https://github.com/PixarAnimationStudios/OpenSubdiv/archive/v3_1_1.zip
2019-11-04 13:07
curl -s -L -o hdf5-1.10.0-patch1.zip.tmp https://support.hdfgroup.org/ftp/HDF5/releases/hdf5-1.10/hdf5-1.10.0-patch1/src/hdf5-1.10.0-patch1.zip
2019-11-04 13:11
curl -s -L -o 1.7.1.zip.tmp https://github.com/alembic/alembic/archive/1.7.1.zip

Build Flags

%PYTHON% build_scripts/build_usd.py --build-args boost,"--with-date_time --with-thread --with-system --with-filesystem" --alembic --hdf5 --no-maya %USD_BUILD_DIR%

[BigRoy]

Note that upon loading the stage from the Alembic file and doing stage.ExportToString I'm getting this output which seems like it does actually load the mesh correctly. Nevertheless, saving that as sphere.usd and then loading results in the same behavior of only showing a bounding box and not showing any geometry whatsoever.

As such, it is reproducable with solely that output saved as .usd too.

[spiffmon]

Hi Roy, I haven’t examined your files, but a have a hunch as to what the issue may be. Alembic files only contain timeSamples (ie no default values), whereas our kitchen set comes from our pipeline where static models only contain default values. I think that the imager, if not configured, reads from the default time. Try configuring the StageView’s current frame with UsdTimeCode.EarliestTime() or zero (or the stage’s startTimeCode, if authored (though it may not be).

On Mon, Nov 4, 2019 at 7:18 AM Roy Nieterau ***@***.***> wrote: Note that upon loading the stage from the Alembic file the and doing stage.ExportToString I'm getting this output <https://pastebin.com/mEaZcQ81> which seems like it does actually load the mesh correctly. Nevertheless, saving that as sphere.usd and then loading results in the same behavior of only showing a bounding box and not showing any geometry whatsoever. As such, it is reproducable with solely that output saved as .usd too. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1022>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABPOU2EQ7EKF2TSLO4BHOZ3QSA4MNANCNFSM4JIUWYZQ> .

-- --spiffiPhone

[BigRoy]

@spiffmon I just figured that out, ha! Since I got the exported Sphere working when I refactored the .usda file manually to not set the points based on time samples but as a single value. But thanks a lot, that was definitely the pointer I needed if I hadn't gone this deep investigating it.

As soon as I added this:

earliest = Usd.TimeCode.EarliestTime()
window.model.currentFrame = Usd.TimeCode(earliest)

The model displayed fine.
As such this issue is resolved.