This A5-sized template helps you to draw perspective lines in an isometric view. Getting the perspective right can make or break a (product) drawing. This template helps you draw help lines every time.
If you want an A4-sized version scale the model 2x in your slicer or print it twice and glue/tape the long sides to each other.

Follow the steps in the pictures to get all the lines drawn. During the tracing process I figured it was faster to use the side of the template for the up/down lines, so I also added a STL of the template without the smaller holes to decrease print time.