What is Caribu ?¶
Caribu is a modelling suite for lighting 3D virtual scenes, especially designed for the illumination of virtual plant canopies such as virtual crop fields. It uses a special algorithm, the nested radiosity (Chelle et al., 1998), that allows for a precise estimation of light absorption at the level of small canopy elements (typically 1 cm2). It takes into account multiple scattering, allows for infinitisation of the scene (by virtual replication) and performs in a reasonable time (typically a few minutes).
The idea is to mix a projection model that solves the first order illumination, a model that solves the radiosity equations for the ligth exchanges between a canopy element and its close neighbourhood, and a model that solves turbid medium equations for the exchanges between a canopy element and the rest of the canopy.
The suite is composed of two main sub-models : MCSail, that computes turbid medium equations on a layered canopy and Canestra, that computes radiosity and projection. The suite also includes two utililities : periodise, that makes a scene suitable for infinite replication and S2v, that transforms a 3D scene in a 1D multi-layer system.
It operates on a special scene object called Caribuscene, composed of a list of triangles with optical properties representing the plants, a set of direction and intensities (called light sources) representing the sky and a pattern delimiting the scene, used for infinitisation.
This model is completed with a set of utilities for visualisation (using PlantGL), import of caribuscene from files or MTG, and tools for building ligth sources from meteorological data
Caribu is released under a specific INRA License agreement. See LICENSE file.