The backbone of the volumetric galaxies made available in this package is a single shader implementation of a specialized ray marching algorithm. The raymarcher shader has a number of parameters that will help you tweak the look and feel of your new galaxy. Below is a listing of the available ones and what impact they have on the algorithm.
This parameter is fairly generic as it affects multiple other internal parameters in the shader. In essence, it will affect the number of final step iterations along with different uses of noise to reduce dithering effects. Please not that a high value will severely affect performance.
Default value: 1
As a virtual ray is shot through the volume, it will accumulate light along the way. This value controls how many steps each ray will take through the volume, starting at the camera position. The number of steps will be divided across the depth of the volume, weighted with an emphasis towards the camera (more samples are taken closer to the camera than far from it). Please note that this value has a large impact on both performance and visual quality. Lower is better in terms of performance. Higher is better in terms of visual quality, to a certain degree. Pushing it too high may result in a form of "shell" effect where the volume begins, as normally very low values of emission may start to become exaggerated due to the number of samples.
Default value: 40
This is a simple multiplier that is applied uniformly to any given sample point in the cloud. Higher is brighter, lower is dimmer.
Default value: 0.20
This parameter will affect how thick the “haze” is within the galaxy volume. It defines the contribution of ambient dust as well as (although indirectly) the thickness of the galactic plane. A side effect of using a high value is that the features of the galaxy will become less defined, whereas a low value will make them become clearer.
Default value: 1
The inner color is used for the core of the galaxy, where you'd normally see a much higher concentration of stars and hence brightness.
Default value: 255, 255, 115, 255
The outer color is the underlying color of the entire galactic plane. It is more prominent outside the galactic bulge where the inner color tapers off, but affects the whole plane.
Default value: 175, 200, 210, 255
Emission and absorption is mainly based on the emission and absorption rates given by the backing texture, but in order to generate cloud like patches and more realistic non-uniformity throughout the volume, a noise function is used to vary emission and absorption. This is the at which the noise function varies.
Default value: 6.0
This is a multiplier that linearly affects absorption across the volume. Depending on your needs, you can let absorption be high or low. Higher values cause regions with high absorption rates to absorb more light. Lower causes them to absorb less.
Default value: 1.5
Think of this as a sort of contrast between areas of high and low absorption rates. It causes highly absorbent regions of the volume to stand out against regions with lower absorption. Higher values yield higher contrast, lower values lower contrast. Please note that this value interacts tightly with exposure, so adjusting this value will likely require adjustment in exposure as well.
Default value: 1.5
This is the base texture which defines the overall structure of the galaxy volume. For more information on how this texture is constructed, please see our FAQ article How do I make my own galaxy?