I assume you are wondering why he is multiplying by 1,1,0 vector.
vector1 * vector2 works like this: x1x2, y1y2, z1*z2
so when he multiplies any vector by 1,1,0
it will nullify Z value (ie snap to ground plane)
This trick is also great for making square grid of meshes:
get integers out of forloop indexes: “nth loop on X” and “nth loop on Y”. Make those 2 into vector, lets call it “index_Vector”
Make vector with sizes on x, y, y for mesh (or spaces in square grid you are making) call it “spacing_Vector”
“index_vector” * “spacing vector” will give you nice grid locations.
much less connections than calculating all values separately.