Here's an overview of how the code is arranged:

Library (LGPLv3):
=================

API:                   libdimension/dimension.h, libdimension/dimension/**/*.h
Ray tracing algorithm: libdimension/render/render.c
Bounding hierarchy:    libdimension/bvh/prtree.{c,h}
Library internals:     libdimension/internal.h, libdimension/internal/*.h
Tests:                 libdimension/tests/*.{c,cpp}
Benchmarks:            libdimension/bench/*.c

Implementations for libdimension/dimension/<module>/<file>.h are generally at
libdimension/<module>/<file>.c

Python Module (LGPLv3):
=======================

Implementation:               libdimension-python/dimension.{pyx,pxd}
Platform-specific components: libdimension-python/platform.{c.h}
Tests:                        libdimension-python/tests/*.py

Client (GPLv3):
===============

Implementation: dimension/dimension.in
Tests:          dimension/tests/*.dmnsn