perceptive height and width of object from distance assume we have a box that measures length of it is about one meter. what is percepted size of it for someone looking to it at 100 meter distance? I'm working on a shooting project that I need to scale 2d hunting goal sprites to make them look from distance.

The perceived size, as the visual angle, can be computed as the angle of a right triangle, with adjacent cathetus of 100m and opposite of 1m. So you can obtain the angle by arctan( 1/100 ) = 0.5729°. If you want to find the size on a projected surface, such as a screen 'd' meters away from the subject, you can use another right triangle with that same angle, with adjacent cathetus = 'd' and opposite cathetus is 's', what you are looking for. Than you have s = tan( 0.5729° )*d = 0.01*d. That can also be thought using similar triangles. Being 'D' the real distance (100m), 'd' the distance of the projected surface, 'S' the real size (1m) and 's' the size on the surface, you also get that s = d*S/D.