Ahhh interesting. You must plan extremely carefully. Do you build the form around the rough idea or is the form just the same boxes that you can use each time? Do you import special sand or just excavate whatever sand is on the beach you're working on?
It's so amazing! And I love your style especially. At first I didn't believe it and thought it was 3D renders. hahaha. But I found videos and stuff. So cool!!
For this one particular case, the forms were pre-compacted. Every contestant had the same forms. Usually, we design form plans according to the sculptures. Plans are rough at best, we just want to make sure we have enough material to carves, but not to much so we don't shovel to much of it for no reason. We use whatever sand the event is whiling to get. Beach sand usually isn't very good, but some places has decent beach sand. River sand and sand digged from quarry are much better for their fine and sharp grains and the natural silt they contain.
Ah ha, yes this makes sense. I was thinking about typical california beach sand and thinking it would be hard to get it to stay. And also that this sand doesn't look that way. Looks very fine and more stable. Very interesting.