Hi all,
The 21.3.1 releases of OpticStudio and OpticsViewer include product Help documentation that is missing equations. We are sorry for this inconvenience to our customers, and we are correcting this error for the next software release. If you are working with 21.3.1 and would like a copy of the Help with the equations included, please login to your Zemax.com account and open a support ticket. Our staff will provide you with a fixed document.