From Eclat-Digital Ocean 2014 Documentation
The null materials is a special material. It is perfectly transparent and invisible, and therefore, does not interact with light.
It has three primary uses:
- For blending with another material using a blend material, resulting in semi-transparency or holes.
- For volumetric effects with no visible surface (such as smoke), as it may be associated with a bulk medium
- For hiding objects without re-exporting the geometry
Ocean XML 2.0 example
<?xml version="1.0" encoding="UTF-8"?> <oceanroot version="2.0"> <material name="nullmat" type="null"/> </oceanroot>