  This article presents new numerical simulation tools, respectively developed
in Matlab and Blender softwares. Available in open-source under the GPL 3.0
license, it uses a ray-tracing/image-sources hybrid method to calculate the
room acoustics for large meshes. Performances are optimized to solve problems
of significant size (typically more than 100,000 surface elements and about a
million of rays). For this purpose, a Divide and Conquer approach with a
recursive binary tree structure has been implemented to reduce the quadratic
complexity of the ray/element interactions to near-linear. Thus, execution
times are less sensitive to the mesh density, which allows simulations of
complex geometry. After ray propagation, a hybrid method leads to
image-sources, which can be visually analyzed to localize sound map. Finally,
impulse responses are constructed from the image-sources and FIR filters are
proposed natively over 8 octave bands, taking into account material absorption
properties and propagation medium. This algorithm is validated by comparisons
with theoretical test cases. Furthermore, an example on a quite complex case,
namely the ancient theater of Orange is presented.
