Your cg problems solved
Sophie Simmonds, Ipswich
Pro artists solve your queries
In real-world photography, rays of light are at their most visible when they have a surface to bounce off, such as dust, pollen or a mist. When these ‘sources’ are unavailable, isolating the light against a dark surface generally works well.
In the virtual computer environment these same beams or shafts of light can be simulated with an effect known as volumetric lighting, or ‘god rays’. God rays might appear when shining through clouds, trees or small cracks in an otherwise dark room.
This effect can be achieved by using a ‘Volume Light’ effect, which is available in the Environment dialog of 3ds Max. Here you can pick a light source for the effect and apply a Density value as well as a Noise and even a Wind Strength value.
However, this Volume Light effect does not work well when using V-ray and it only produces results when linked to a ‘standard’ direct light source.
If, like me, V-ray is your render engine of choice, then the best way to produce these god rays is to use the environmental effect Vrayenvironmentfog. This is able to very quickly and easily produce the desired effects.
After attaching a light source from your scene to this effect, the density of your rays will be affected by the light intensity values, and the controls in the Effects dialog box can determine the length,
colour and density of the beams and their overall ambient affectation.
As an additional finish to the atmospheric drama you could also add dust particles to your scene using a particle cloud from the Particle Systems dropdown. Alternatively, there is a handy script named ‘Goldendust’ (vint26. wordpress.com/scripts/goldendust) available online, which similarly is able to quickly create a particle cloud formed from your own bespoke geometry-based particles, for realistic-looking dust. Or, if you prefer and it is appropriate to your scene, the script also has a nice readymade dandelion fluff that comes as part of the plugin.