This is such a great question! Thanks for asking it, @henryquach.
Getting multiple simulation tools on your resume is a great asset! Not having enough definitely hampered my job search progress during my sub 5 years industry experience mark. I was specifically told this by hiring managers.
I’ve had to speed-learn LightTools, TracePro and Photopia (at the same time!) when I needed to 1. produce a working design when I immediately started working at a company and 2.) make a recommendation to upper management on which sw they should purchase.
From that experience especially, I would have to agree with @lrgraves and disagree with @hkang on the ease of learning a new program! It’s not easy, and even after you have a hang of the new sw, you’ll often get into situations where you have to dig into the specfics on how each sw calculates each part of the ray path. What look like minor, inconsequential differences here can make the difference between a design that passes a regulation and one that does not.
Out of the programs you mentioned, Henry, I’d say ASAP is the one I ran into most in industry. TracePro would be second.
FRED I saw at only one company and it was just this one dude who refused to use ASAP cuz he thought FRED was the bom. I thought it was not, in fact, the bom. I think @lrgraves has fonder feelings for FRED but I wasn’t really impressed when I tried to learn on a trial version about 8 years ago. But, of course, that was a while ago, so maybe it’s fancier now.
If you need to create geometry, as you often do in illumination design, LightTools is great - for the most part I can get by today with just LT and no separate CAD package, so long as I’m working with an ace ME who can turn my mess of geometry into something beautiful – outside of the functional surfaces.
If you have, say, SolidWorks already and are comfortable with it, I’d say ASAP would be a good one to move to next. I see ASAP used often in industry not just for design, but for separate job functions that just exist for things like stray light analysis.
However, if you need to create geometry and don’t have access to a CAD program for you next project, TracePro might be better. It’s definitely not as easy to create structures in TracePro as with LightTools, but it’s a lot better than what you have (last I played with it many years ago) in ASAP.
Otherwise, if you can get your hands on one of the SolidWorks plug-in type programs, that might be nice to check out. Breault’s (ASAP maker) plug-in-aka-“add-in” version is called APEX http://www.breault.com/software/about-apex
Again, though, you’d also need a SolidWorks license for this. There are a lot of other plugins for SolidWorks with other optics sw, by the way! There is one for Zemax, LightTools, LucidShape… etc.
In any case, yeah, get as many sw programs as you can on your resume! Best of luck to you.