[kjfi]

I could not find 2ft x 2ft plastic lens es for my lights so I bought 4ft x 2ft and will cut them in half except they started cracking.

[ma0641]

You need an acrylic cutting knife. It is a knife with a very small hook end that grooves the sheet so it can be snapped. Definite PIA to cut sheet, particularly cheaper styrene.

[smearcase]

Possibly with the material clamped between two pieces of plywood or other wood, then using a paneling (fine) blade placed backwards (front of blade becomes the back side) in a circular saw..
That is how I would try to cut it, like the way I have cut some types of plexiglass but I have never tried it with the lenses you have described. Wear safety glasses in all cases and good luck.

[drtom4444]

I have cut that cheap material and you need to clamp it and use a plexiglass knife to cut it. Make sure and score the material almost all the way through before trying to snap it in two. Any error and it will break wrong.