Blender is open source 3D graphics software, primarily for ray tracing, but whose capabilities also include animating, rendering, video editing and compositing. Ray tracing is a computer graphics technique used to model surfaces, which creates realistic shadow and lighting effects. The technique models the path of light rays backwards from an imaginary eye, through each pixel in a virtual screen. Each ray is tested for intersection with the objects in a rendered scene, and once the nearest object is identified, the incoming light at this point is combined with the material's texture and properties to calculate the correct colour for a given pixel. If the object is reflective or refractive, further rays are cast into the scene, until a maximum number of reflections or maximum distance without intersection is reached, and the pixel colour can be updated. This allows highly customised lighting, textures, and appearance when rendering 3D models created by X-ray microtomography.


The software is freely available at