 SURFACE DISTANCE blends between two parameters based on the surfaces distance from the
camera. The primary purpose of this component is to let you add more detail at close camera distances and reduce detail at larger distances to prevent aliasing artifacts.
How Does It Work?
SURFACE DISTANCE calculates a blend between two colors, two percent values, or two distinct bump
patterns. It does this by determining the distance of each surface point from the camera and comparing that to a Near a Far value.
The actual values for Near and Far are defined in the Simbiont plugin you are using to render the DarkTree.
For example, you might have a Near value of 3 meters and a Far value of 100 meters set in your Simbiont plugin. The Near Distance and Far Distance in the SURFACE DISTANCE component are then mapped to
this range so that a Near Distance of 0% means 3 meters and a Far Distance of 100% means 100 meters. The SURFACE DISTANCE value gradient will smoothly blend between 3 meters and 100 meters distance from the camera.
Note: SURFACE DISTANCE only works when the DarkTree shader using it is rendered through a Simbiont plugin. Bitmap output cannot take advantage of camera location and so cannot utilize SURFACE
DISTANCE.
Hints!
SURFACE DISTANCE can dramatically improve the rendering quality of large scale 3D scenes. A common
example is terrain fading off in the horizon. Usually, you have to compromise between the quality of close
up terrain and distant terrain. If you have too much detail in the close up terrain, you will run into aliasing
artifacts at a distance. The other alternative is to have low detail terrain which doesn't look as good close up but renders well at a distance. Using SURFACE DISTANCE, you can have the best of both worlds.
Figure F1below shows a simple example of decreasing detail with distance. The "far" Rough component has reduced Roughness and Contrast.
With distance, you will usually want to reduce the amount of detail in your shader. You can do this by
reducing the roughness and contrast of the far texture. For highly detailed surfaces, you can blend the detail out all together. Bump textures are highly sensitive to aliasing and so you will often want to reduce
bump scale to zero at large distance. Bump can be replaced by a darkening the color of your surface based on the Bump pattern. For optimum results, you can use the Near Distance and Far Distance parameters to
blend different details in your darktree at different distances.
You can also think in terms of adding detail to your texture as you get closer. For example, you could make
a texture that lets you zoom into skin until you see individual cells. Just keep adding details as the camera gets closer.
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