Hi there,
The snow device exists to model the accumulation of snow on the terrain; depending on the settings you can accomplish everything from light dustings of snow to glacial models…
Here’s a good howto:
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Start with a basic default world consisting of an advanced perlin noise device. Add a snow device and hook it up to the perlin.
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Next we want to make sure sure you can clearly see what effect the snow device is having on the terrain.
[ul][li]Create an overlay output device and hook it up to the snow device. Then hook the depthmask from the snow device to the second input of the overlay, and turn up the “mask ambient” in the overlay device. [/li][/ul]
What you’ve just done is made it so that snowy areas will be indicated in white on the terrain; this makes it very easy to see what exactly all the settings of the snow device are doing!
[ul][li]Now freeze the view on the overlay output (select it, hit ‘f’) and open up the device window for the snow device. [/li]
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The important controls are as follows:
Intensity: How much snow is deposited each cycle
Evaporation balance: How much snow evaporates/sublimates each cycle. This is a ratio, where 1.0 (the default value) means that on average as much snow is lost as is gained each year. Thus only deep accumulations will survive. If you want to accumulate snow, slide this to the left.
Snow Amount: How long to run the simulation for. Together with Intensity determines how much snow is put onto the terrain. Why raise this instead of intensity? Snow will slowly soften and compress over time, so a high snow amount but low intensity will snuggle snow down into cracks and smooth out more than a high intensity but low amount. A high value in both will really dump the snow on your terrain.
Snow Line: This is what you want for snowy peaks! In general, evaporation of the snow increase as the elevation goes lower; this value sets the cross-over elevation whereby snow will or will not survive. Increasing this value clears the lowlands of snow, retaining it just up high in the mountains.
Finally,
Depthmask cutoff: This scales how deep the snow is considered to be. Think of it as a scale saying “how many inches of snow do I need before I consider the terrain to be snowy?”
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Hope this helps! I actually have a fantastic example world for using the snow device for a snowy peak; it uses a currently unreleased device but I will see if I can modify it and post it to this thread soon.