Resolvers

Asset resolvers that can be compiled via this repository:

  • Production Resolvers
    • File Resolver - A file system based resolver similar to the default resolver with support for custom mapping pairs as well as at runtime modification and refreshing.
    • Cached Resolver - A resolver that first consults an internal resolver context dependent cache to resolve asset paths. If the asset path is not found in the cache, it will redirect the request to Python and cache the result. This is ideal for smaller studios, as this preserves the speed of C++ with the flexibility of Python.
  • RnD Resolvers
    • Python Resolver - Python based implementation of the file resolver. The goal of this resolver is to enable easier RnD by running all resolver and resolver context related methods in Python. It can be used to quickly inspect resolve calls and to setup prototypes of resolvers that can then later be re-written in C++ as it is easier to code database interactions in Python for initial research.
  • Proof Of Concept Resolvers
    • Http Resolver - A proof of concept http resolver. This is kindly provided and maintained by @charlesfleche in the arHttp: Offloads USD asset resolution to an HTTP server repository. For documentation, feature suggestions and bug reports, please file a ticket there. This repo handles the auto-compilation against DCCs and exposing to the automatic installation update manager UI.

USD Plugin Configuration

In order for our plugin to be found by USD, we have to specify a few environment variables. Run this in your terminal before running your USD capable app. If your are using a pre-compiled release build, redirect the paths accordingly.

Tip

If you are using our quick install method, this will already have been done for you via the "launch.sh/.bat" file in the directory where you downloaded the compiled release to. See our Automatic Installation section for more information.

# Linux
export PYTHONPATH=${REPO_ROOT}/dist/${RESOLVER_NAME}/lib/python:${PYTHONPATH}
export PXR_PLUGINPATH_NAME=${REPO_ROOT}/dist/${RESOLVER_NAME}/resources:${PXR_PLUGINPATH_NAME}
export LD_LIBRARY_PATH=${REPO_ROOT}/dist/${RESOLVER_NAME}/lib
export TF_DEBUG=AR_RESOLVER_INIT # Debug Logs
# Windows
set PYTHONPATH=%REPO_ROOT%\dist\%RESOLVER_NAME%\lib\python;%PYTHONPATH%
set PXR_PLUGINPATH_NAME=%REPO_ROOT%\dist\%RESOLVER_NAME%\resources;%PXR_PLUGINPATH_NAME%
set PATH=%REPO_ROOT%\dist\%RESOLVER_NAME%\lib;%PATH%
set TF_DEBUG=AR_RESOLVER_INIT # Debug Logs

If it loads correctly, you'll see something like this in the terminal output:

ArGetResolver(): Found primary asset resolver types: [FileResolver, ArDefaultResolver]

Debugging

By using the TF_DEBUG environment variable

To check what resolver has been loaded, you can set the TF_DEBUG env variable to AR_RESOLVER_INIT:

export TF_DEBUG=AR_RESOLVER_INIT
For example this will yield the following when run with the Python Resolver: 
ArGetResolver(): Found primary asset resolver types: [PythonResolver, ArDefaultResolver]
ArGetResolver(): Using asset resolver PythonResolver from plugin ${REPO_ROOT}/dist/pythonResolver/lib/pythonResolver.so for primary resolver
ArGetResolver(): Found URI resolver ArDefaultResolver
ArGetResolver(): Found URI resolver FS_ArResolver
ArGetResolver(): Using FS_ArResolver for URI scheme(s) ["op", "opdef", "oplib", "opdatablock"]
ArGetResolver(): Found URI resolver PythonResolver
ArGetResolver(): Found package resolver USD_NcPackageResolver
ArGetResolver(): Using package resolver USD_NcPackageResolver for usdlc from plugin usdNc
ArGetResolver(): Using package resolver USD_NcPackageResolver for usdnc from plugin usdNc
ArGetResolver(): Found package resolver Usd_UsdzResolver
ArGetResolver(): Using package resolver Usd_UsdzResolver for usdz from plugin usd

By loading the Python Module

When importing the Python module, be sure to first import the Ar module, otherwise you might run into errors, as the resolver is not properly initialized:

# Start python via the aliased `usdpython`
# Our sourced setup.sh aliases Houdini's standalone python to usdpython
# as well as sources extra libs like Usd
usdpython

# First import Ar, so that the resolver is initialized
from pxr import Ar
from usdAssetResolver import FileResolver