Here’s an example:

Surface 2 is wedged with respect to surface 3 by line 10 in the tolerance editor. Line 9 TETZ rolls the component formed by 2 and 3 to be anywhere between 0 and 360 degrees.

• Mark

That’s a good point Jeff, thanks.

Another thing just occurs to me. When we design a doublet, we can use a short cut that sequential ray tracing provides and model the doublet using only three surfaces. But when tolerancing, in other to get the kind of offset Jeff shows in his reply, it’s essential that you model the doublet as two separate singlets: in other words you need to use four surfaces to define the doublet, not three. Each singlet uses two independent surfaces.

Now during optimization, we can use only three surfaces because the rear of element 1 must have the same radius of curvature (etc) as the front surface of the second element. But for tolerancing the doublet, you must allow them to be different, so they can have slightly different curvatures as well as positions.

OpticStudio does this automatically for you when you export to CAD or convert to NSC, as these are true 3D solid models. But you have to do it yourself for tolerancing. There’s a long-standing feature request to add this capability to the Design Lockdown tool, but for now you have to do it yourself.