Is it possible to create an Alembic Layer export using Python?

[paul hormis]

I have an issue where I am given a large VrayProxies that  is loading an Alembic.

I created a tool that checks which objects are within the camera frustum of the shot and I want to animate the visibility of them using an Alembic Layer in the VrayProxy.

This is in 3ds Max.  I am using Python and not C++ for this work.

Is it possible?

[Lucas Miller]

Yes, I think all you need to do is sparsely create the hierarchy as OObjects, and then use alembic.AbcGeom.CreateVisibilityProperty  on the OObject where you want to create the property that will be animated.

Lucas

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[paul hormis]

Could you possibly point me into the direction of documentation or examples of this?  I am new to the Alembic API.

[paul hormis]

Thank you for the very quick reply.

[Lucas Miller]

I couldnt find a relevant test in the python binding, so instead I whipped up this example:

import alembic arch = alembic.Abc.OArchive('/tmp/vislayer.abc')

# lets sparsely set visibility on /foo/bar/baz 

fooObj = alembic.Abc.OObject(arch.getTop(), 'foo')

barObj = alembic.Abc.OObject(fooObj, 'bar')

bazObj = alembic.Abc.OObject(barObj, 'baz')

# assuming 24 fps, have a sample for every frame that starts at frame 101 

ts = alembic.AbcCoreAbstract.TimeSampling(1.0/24.0, 101.0/24.0) 

visProp = alembic.AbcGeom.CreateVisibilityProperty(bazObj, ts) 

 # -1 means deferred visibility, which is implicitly visible unless an ancestor marks it as invisible.

 # 0 means invisible 

visProp.setValue(-1) # frame 101 

visProp.setValue(0)  # frame 102 

visProp.setValue(0)  # frame 103 

visProp.setValue(-1) # frame 104 

visProp.setValue(0)  # frame 105

Lucas

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