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Root » Solaris and Karma » Layer attributes from VEX

jparker

Nov. 21, 2020 22:30:36

How do I get layer info with VEX?

I want the layer's scale info, so I tried this:

float unitscale = usd_metadata(0, '/', 'metersPerUnit');

But I get a zero instead of the right unit. Is this wrong? Sorry if I'm spamming the forum with obvious questions…

agelosc

Nov. 23, 2020 12:59:27

I'm not sure about vex but you can easily get anything with a python node and the pxr USD API. For example

from pxr import Usd

stage = Usd.Stage.Open(<usd file path>)
unitscale = stage.GetMetadata("metersPerUnit")

There is already a stage variable when you create a python lop which is the conne ted stage so you can possibly skip the whole Usd.Open() line.

I might have syntax errors but hope it paints a picture. Documentation for the USD python API is a bit tricky but it's worth looking into it.

rafal

Nov. 23, 2020 13:49:37

It should work. Looks like a bug. Quick check shows that USD API method `UsdStage::GetObjectAtPath(“/”)` does not return the pseudo-root object for some reason.

jparker

Nov. 23, 2020 14:20:11

I see, I also just tried to get the information with Python and got this error:

>>> stage.GetObjectAtPath('/').GetAllMetadata()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
RuntimeError: Accessed <pxr.Usd.Object object at 0x7f234d02b2f8>

while something like this works in a parameter expression:

pwd().inputs()[0].stage().GetMetadata('metersPerUnit')

jparker

Nov. 23, 2020 14:26:40

I'll file a bug and send an example scene (and reference this thread).

jparker

Nov. 23, 2020 14:49:24

Bug #109661