void draw_2d_fit(RendererViewport r, OpticalSystem system, bool keep_aspect)
{
Vector3Pair b = system.get_bounding_box();
r.set_window(Vector2Pair.from(b, 2, 1), keep_aspect);
r.set_camera_direction(Vector3.vector3_100);
r.set_camera_position(Vector3.vector3_0);
r.set_feature_size(b.v1.y() - b.v0.y() / 20.0);
}
void draw_2d(RendererSvg r, OpticalSystem system)
{
// optical axis
Vector3Pair b = system.get_bounding_box();
r.draw_segment(new Vector2Pair(new Vector2(b.v0.z(), 0.0), new Vector2(b.v1.z(), 0.0)), Rgb.rgb_gray);
foreach (Element e in system.elements())
{
draw_element_2d(r, e, null);
}
}