I don't know how egui or the OP's app works, but we aren't talking about costly intersections of arbitrary surfaces but the sending of vertex data (for the vert

I don't know how egui or the OP's app works, but we aren't talking about costly intersections of arbitrary surfaces but the sending of vertex data (for the vertex shader) in an integer interval (of nodes). This isn't about half or 1/10, but about 1/1000th of the data.