I have several paraxial lenses, mirrors and a Grid Phase Surface (imported as .DAT, see attached) in the beam path to start with. The issue I am having is that the model gets increasingly slow and unresponsive when I try to import the .DAT for additional Grid Phase Surfaces. For instance, it takes several minutes simply to import the .DAT using Surface>Import>Import Data File>.DAT. Once the .DAT file has been imported, any further adjustment (say, changing the ‘Interpolate’ parameter of the Grid Phase) makes OpticStudio unresponsive and takes several minutes to take effect. For your reference, I am using a Premium license of OpticStudio 23.1.3. Please share any tips to resolve this issue. Thanks!