Mathematically precise bisect cuts? https://youtu.be/raWx4MYjq-4
^^^^^^ Example ^^^^^^^
Hi. Is it possible to make precise bisect cuts in Blender? I can only make them manually, by hand, and imprecisely.
For example, like in the video, say I wanted to bisect the object exactly on one of the 3 lines that you see there. I did it by hand in the example.
I know there are numbers in the Bisect window, but I'm not sure how to operate them. There's no &quot;angle&quot; or anything (which would be helpful, because in this case I could set the bisect to 72 degrees for example (but unfortunately it's not angle based)).
Is this possible?
Well, that's not an easy interface to interpret, is it? First, in the top part of the window is &quot;Plane Point&quot; this is a point on the cutting plane. In your case, I think you should set it to the origin (0,0,0). This is also the pivot point for angle adjustments.
The second part of the window is &quot;Plane Normal.&quot; For the Y-Z plane, set it to (1,0,0).   For the X-Z plane, set it to (0, 1, 0) and for the X-Y plane, set it to (0,0,1). In the attached screenshot, it is set to (cos(72°), sin(72°), 0) and the poorly drawn white arcs show 72° for the normal referenced from the x-axis and 72° for the cutter plane referenced from the y-axis.
To further expand, lets cut out Suzanne's face at +/1 36°. I put sin(36°) and cos(36°) into a calculator and got 0.588 and 0.809 so lets see how to put those in: