Determining distances between points on two surfaces
Question
Several times I have had the need to measure a distance, say from the front surface of a lens to the aperture stop, or the length of a group of lens elements (for example, surface 5 to surface 11). Is there an easier way of doing this than manually adding up all the thicknesses? What happens if I have tilts and decenters on the intervening surfaces?
Synopsis
Determining distances between points on two surfaces
Solution
"OSLO does this calculation when the user implements the Edge Thickness (eth) command from the OSLO menu:Lens>>Show Auxiliary Data>>Edge Thickness
If you want the on-axis distance between two surfaces, just enter zeros for the X and Y heights.
Any tilts and decenters between the surfaces of interest will be taken into account.
In the output:
The X, Y and Z distances will be reported in the coordinate system of the current Global Coordinate Surface (gcs). This can be changed in the General Conditions dialog ("Global ref. surf. for ray data") and the Edge Thickness command can be repeated.
The "Global Distance" is absolute and is independent of the current Global Reference Surface.
