STEP 10: ANALYZING A SNOWFLAKE
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If you do want to try and copy a snowflake that you see, or at least get an idea of how to make one similar, try to visualize the slice of the snowflake that represents the completely folded paper. This is one slice out of twelve symmetrical slices. It will be a line that cuts through the middle of one point, and intersects with a line cut though the middle of the "valley" between it and the adjacent point. If it makes it easier, pretend that the snowflake is a clock and the lines you're imagining are the hands when it's one o'clock. See picture.
This slice of the snowflake shows what your cuts should look like if you want a snowflake that looks like this. It may be easier to visualize if you look at the black (cut out) spaces and think about those shapes being cut away. This is how you can make a "template", in a way, based on snowflakes that you see.
STEP 11: REPLICATING A REAL SNOWFLAKE
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From time to time I try and copy a real snowflake that I see in a book or online. It's impossible to copy an actual snow crystal exactly because they're simply too intricate, they're 3-D, and some parts of the snowflake are attached with a layer of ice so thin that it looks invisible.....if you tried to copy one exactly, it would fall apart. However, you can still try to mimic the form of a real snowflake.
Real snowflakes often have large areas of "blank space" that don't look very good when rendered in paper. A flip through a snowflake photography book shows that quite a few snowflakes form as just a simple hexagon with few details. If the snowflake you're copying has a lot of blank space, embellish it anyway. Since it can't be an exact replica, it might as well be pretty!
Basically, just use the technique from step 10. Imagine the how a real snowflake would look if it were a slice of a pie. Think of the clock hands at 1 o'clock.
Above are two examples of snowflakes that I've tried to replicate. I've added a second view of each with the "slice" highlighted.