Debugging

The Usd API ships with a debug class, which allows you to log different messages by setting the TF_DEBUG environment variable to one of the symbols. This is useful to see if plugins are loaded or to see if the asset resolver is correctly hooked in.

TL;DR - Debug In-A-Nutshell

• You can set the TF_DEBUG environment variable to one the the values listed below or symbol name from a plugin.
• You can also activate a symbol in the active session via Python: pxr.Tf.Debug.SetDebugSymbolsByName("AR_RESOLVER_INIT", True)

What should I use it for?

Resources

• Debug API Docs

Overview

Environment Variables:

export TF_DEBUG=AR_RESOLVER_INIT

activated_symbols = pxr.Tf.Debug.SetDebugSymbolsByName("AR_RESOLVER_INIT", True) # Returns: ["AR_RESOLVER_INIT"]
activated_symbols = pxr.Tf.Debug.SetDebugSymbolsByName("AR_*", True)

External plugins (like asset resolvers) often register own debug symbols which you can then use to see exactly what is going on.

To get a list of value TF_DEBUGvalues you can run:

from pxr import Tf
# To check if a symbol is active:
Tf.Debug.IsDebugSymbolNameEnabled("MY_SYMBOL_NAME")
# To print all symbols
docs = Tf.Debug.GetDebugSymbolDescriptions()
for name in Tf.Debug.GetDebugSymbolNames():
    desc = Tf.Debug.GetDebugSymbolDescription(name)
    print("{:<50} | {}".format(name, desc))

Full list of debug codes:

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