Describes: spherical volumetric lights, projector lights, animating textures, distance attenuation.
Brushmaps and procedural textures can be applied to Volumetric Lights to produce so called HyperTextures, solid volumes viewable from any angle, like gas or solid fog. Even on the still image, the 3D nature of the volumet ric effect can be appreciated, but it shines in animation. There are no transparency layers, no 2D coloring, hypertexturing is true volume integration.
Add a Pointlight and select it. Open Lights Panel with F7, the Pointlight will be selected here as well since it was selected in the editor. Turn on Volumetric property for it, change attenuation form Off to Linear and close the panel. Test render in mode 8. The result is far from being exciting: a white disk that fades to gray. Reopen Lights Panel, set light Intensity to 100%, Far Distance to 100.0 and activate Distance Dim as Linear Range, entering 75.0 as near dis tance.
Linear and Linear Range attenuations
In real world light's intensity decreases with distance but this property is seldom used in computer graphics because it's very difficult to balance light levels. Linear Range is an invaluable light property that has no real world counterpart and allows for precise illumination control. A Linear Range light is at full intensity in the range from its center up to its Near Distance, then decreases to zero when it reaches the Far Distance.
Preview again the image, now the white disk looks like a soft, fading halo, with a bright inner core. Much better, and already suitable for a planet's atmosphere.
Enter Materials Panel and apply Clouds.ptx texture to the light lowering the number of Octaves to 5 to speed up rendering. Accept, go in Light Panel and turn on Projector Light property. Preview again, this time it will be much slower but a nice cloud colored soft sphere will be visible.
Change Projection method in light panel setting it to Intensity, this way the clouds texture will not color the sphere, controlling its intensity instead. Save the project, then enter Animation mode with Tab.
The volumetric sphere hypertextured with clouds
In Frame 1 open Materials Panel and change U,V,W Tile to 2.0, 2.0, 2.0. Accept, and this will create a Props Morph pose for the light. Delete timecode gadget contents and enter 25, this absolute frame number will turn into a timecode and the editor will be updated.
Open Materials Panel again, change U,V,W Tile to 5.0,5.0,5.0 and V % to -5.0. Accept, save the project and do a test rendering of the resulting animation. It will show the gas ball as if it was made of smoke that moved towards its center and upwards as well.
As a final test, try changing both the light's color and to increase number of volumetric samples (remembering that gas is an additive effect that can even change the tint of the colors).