IES utilities

Utilities for reading and using .ies files (IESNA LM-63 Format), which are used to describe lights.

The files ies.h and ies.cpp are originally from Cycles, a path-traced renderer that is a spinoff of the larger Blender project, though available with in own repository, and via the Apache 2.0 license:

• https://projects.blender.org/blender/cycles
• https://projects.blender.org/blender/cycles/src/branch/main/LICENSE

Version

v4.1.1 ( 234fa733d30a0e49cd10b2c92091500103a1150a )

Setup

When updating IES, the following steps should be followed:

1. Copy src/util/ies.h and src/util/ies.cpp over the copies in pxr/imaging/plugin/hdEmbree/pxrIES.

2. Apply pxr-IES.patch to update the source files with modifications for USD, ie, from the USD repo root folder:

   shCopy

   patch -p1 -i pxr/imaging/plugin/hdEmbree/pxrIES/pxr-IES.patch
   

3. Commit your changes, noting the exact version of blender that the new ies files were copied from.

If the update requires manual merging, the patch file can be regenerated with

diff -ruN <path to original ies.h> <path to new ies.h> > pxr-IES.patch.
diff -ruN <path to original ies.cpp> <path to new ies.cpp> >> pxr-IES.patch.