How do you cut a sun strip as straight as possible without a plotter?

Answer 1: Place a 12-inch piece of film on the roof and use the top of the windshield as a guide to create a curved edge.    Answer 2: For most sedans and coupes, you can actually use the back glass as your guide.    Answer 3: If the edge of the glass isn’t exposed, you can use a sharpie to mark the top of the windshield and use a peel board to cut it freehand after folding the film in half.    Answer 4: Use the bottom edge of the windshield/gasket as a guide.