Can I use my existing SolidWorks license instead of the one integrated in APEX?
No, APEX is a standalone product. It is not an add-on to SolidWorks, but rather a seamlessly integrated optics- and CAD-software platform. APEX files are SolidWorks files so they can be read by your existing SolidWorks software (and vice-versa), allowing you to make maximum use of your existing software infrastructure.