Some Details

The final implementation includes now

attenuating density fields
emitting density fields
glowing density fields and the scattering effects of lit
haze and
dust.

The paricles of the density field have all a special transparency, which can be traced in a wide variety of density distributions. The whole transparency of the cloud is then mapped on a color table giving different colors for different opacities. Results are here.

In this case every particle emitts light of a certain colour, depending of the differential density there. The accumulated color gives the color of the glow or halo. Results are here.

This more physically based modell assumes the same light emission of every particle as an emitting object, but the light of each particle is attenuated by the particles lieing in front of it towards the eye. This gives nice color X-Ray effects. Results are here.

To modell the effect of a lit hazy atmosphere, one has to consider a lot of things, like different types of phase functions for the scattering of light. Then You've to decide to modell multiple scattering effects or not, what happens with colored lights, and so on. The dust modell implements a Mie-haze phase function, giving much light scattered in the forward lobe. Results are here.

To give more freedom on creating fog effects, I implemented the Henyey-Greenstein phase function approximation with a controllable parameter, to select different intensity distributions around the particles. Results are here.

Last update May 2th, 1996
Created by Zsolt Szalavári