Serializing large Usd files into maya ASCII crashes maya about al_usdmaya

[alekamca]

Python script to reproduce at least in our environment (Maya 2018 Update3):

# from within maya batch mode
from maya import cmds as mc
from pxr import Usd, Vt, Sdf

print 'creating usd stage'
# create usd stage with a large ascii representation
stage = Usd.Stage.CreateNew('tmpStage.usda')
prim = stage.DefinePrim('/prim')
attr = prim.CreateAttribute('doubleArray', Sdf.ValueTypeNames.DoubleArray)
arrayValues = Vt.DoubleArray(1000000, 1.0/3.0)
attr.Set(arrayValues)

# import stage
print 'importing stage'
mc.AL_usdmaya_ProxyShapeImport(f='tmpStage.usda')

# save file
print 'saving'
mc.file(rename='test.ma')
mc.file(save=True,force=True,type="mayaAscii") #crash occurs here
print 'done'

[dbaz]

Havn't thought about it too deeply, but you could update the LayerManagerNode to have the option of saving out a sidecar usda file that contains the contents instead of having it inline. The contents could change to being the filepath to this sidecar file and the identifier kept the same.

At this stage I don't think we would use it, we have already had problems with sidecar files where artists would move around their Maya file, or just delete the sidecar files, and essentially breaking their Maya file or losing data.

[murphyeoin]

We're going to look at this one soon - it's important to get this working

[robthebloke]

I'm taking a look at using a custom MPxData attribute type to work around the hard limit. Ideally when in the land of *.mb files, I'd prefer to serialise out as a usdc binary blob, however there doesn't seem to be a way to do this in USD currently. Question asked here....

https://groups.google.com/forum/#!topic/usd-interest/_WVE4tHojdc

I'll give it a go with strings, and put a PR up for you to test....