Hi Ruik,

Sequential mode is inherently setup differently than non-sequential mode in terms of positioning elements.  As the name implies, each surface is sequentially placed with respect to the surface immediately before it.  In order to mimic global positioning in sequential mode, you will need to use Coordinate Breaks with Coordinate Returns.  The concept is as follows:

• Define a global XYZ surface
• Use one Coordinate Break before the surface to position the XYZ vertex
• Use a second Coordinate Break before the surface to tilt the vertex
• Place the surface(s) you want at that given position
• Use a third Coordinate Break/Return to change the coordinate system back to the global XYZ surface

I have a LinkedIn post which describes this and also has a ZPL macro which allows you to position mirrors in global XYZ space.  If you have lens elements, then you can go back into the modified LDE and change the mirrors to lenses.

Post | Feed | LinkedIn

As for converting from Non-Sequential to Sequential, there is no built in tool that does this.  You’ll need to manually convert any file back to sequential mode.

Hi Michael,

Thank you for your detailed explanation, it is very helpful.

in fact, for complex off-axis optical system, the local coordinate often confused me. For example, a coordinate break surface is has 0 distance or some distance to it, the effect to the element following it will be of huge difference.  If the optical elements,  each has 6 different coordinates (x,y,z, theta, phi, zeta ), the complexity is definitely expected.  

On the opposite, if layout can be set in NSC mode, then convert to SC mode, if possible, will be convenient. The fact is it can not. Only convert discussed in zemax is from SC to NSC mode.  Now it seems the development and research is slowed down by the skills of optical software but not knowledge.  

I’ll check your zpl macro. have questions, I will ask you. Best