This is a parametric pipe cutting jig. You can customize the pipe diameter, the blade thickness, the tolerances, the total lenght and more in Fusion360 by changing user parameters.

It can be used as is or mounted on a board using double-sided tape, glue or screws. If mounted, it will retain its function even if you cut through it.

It provides support for longer lenghts of pipe to make holding the pipe in place easier and uses a narrow slit to guide the blade more reliably (the width of the slate can be customized).

The STL model is for a 50mm pipe and a thin hacksaw blade (about 0.6mm with a tolerance of 0.1mm) with a total lenght of 200mm.

Since this is a functional part and doesn't have to be pretty, I recommend 0.6 line width, 0.28 layer height, about 20% cubic/gyroid infill and PETG.