by **origami_8** » July 23rd, 2019, 6:12 pm

So, second try. In the morning I wrote a lengthy reply and when I hit the submit button it told me to log in and all the text was gone (yes, it even sometimes happens to moderators). Unfortunately I then had to leave, but now I'm back home.

First of it depends on the program you are using and other ways may lead to the same result.

My approach to diagramming situations like in the first and last step would be to measure it on a paper sample and then transfer the measurements onto the drawing. Like lets say if I have a 9cm square and the line I want to draw starts 7cm from the left upper corner along the top edge, I'd take this measurement and calculate the percentage like (7/9)*100, what gives me around 77.78%

Then I'd draw a reference line as long as the upper edge of the square and resize it to the calculated value. The reference line should be placed along the upper edge so that one end touches the left corner.

Next on I'd repeat the same procedure on the lower edge, with measuring, calculating, drawing,...

Last step is to connect the ends of the two reference lines with the new fold line and delete the now unnecessary reference lines.

For steps two and three, if the program you use has no way to divide an angle by a set value, it can be done with a reference circle. The circle should be placed with the middle point touching the point where the two lines that you already have meet. Now draw a line that goes from where the edge of the circle meets the one line, to the point where it touches the other line. With most programs I know you can now just add a mid point to that line. (If that doesn't work, resize the line to 50%.) A line that goes through the mid point of the circle and this new point divides the angle. Afterwards the reference circle and line can be removed.