i know it looks the same, and its not perfect, but this is a basic expanding RT_BEAM equvilant.
spawn effect at cgame.
i can't figure out how q3 did it, but what i'm thinking is that the engine is given the start and end position. why its an engine-only in q3 i have no idea.
engine figures out the origin of the poly, its a 4 faced poly shaped like a star. the engine orients it from start to end point, then scales it from 1/2 of the distance to start to end basically blowing it up from the middle to each point then draws it. least thats how i think it happens after slowing down q3 to frame by frame.
cgame effects are fun to work with.
