I have as long as I can remember been a very big fan of snow. Therefore I decided to produce a snow material in UDK. My ambition was to make it as realistic as possible. I also wanted to get that “sparkle” effect that you get when you look at snow from different angles and the sunlight hit different small surfaces, just right.
The next thing that I needed to do was how the snow was going to hit objects. My initial idea was that I would try to utilise a so called modulus math solution. By doing this I would just have to create a big sprite sheet in which I can draw exactly how I want each snowflake to fall. This did unfortunately not look as good as I thought it would.
I quickly moved on after that. What I finally decided to use was an other type of texture where I painted in small dots (my snowflakes) in grayscale, black to white. I then used a LinearInterpolate node to use my painted texture as an Alpha and then black and white as A and B values. I could then use an If node to go through the texture, from black to white letting the snow cover more and more ground over time.
Here is a close-up on the small sparkle effects in the
snow material. These little sparkles are based upon a
camera vector which gives them this cool effect.