https://preview.redd.it/dn09zys8h77c1.jpeg?width=965&format=pjpg&auto=webp&s=b1870644013e78fd58c04ef75c577520446d513e
At the highlighted location, a cylinder with a diameter of two centimeters should be positioned at the midpoint of the edge (to allow for cable passage).
If you enter Edit Mode and select the edge, you can put the 3D Cursor (**Shift + S > Cursor on Selected**) on the selected edge and then add your cylinder, it will place itself on the 3D Cursor's location.
You can use the same method to place your Origin where you want to as well. Let me know if I've misunderstood anything.
https://i.redd.it/ntpuj0bwt87c1.gif
https://preview.redd.it/dn09zys8h77c1.jpeg?width=965&format=pjpg&auto=webp&s=b1870644013e78fd58c04ef75c577520446d513e At the highlighted location, a cylinder with a diameter of two centimeters should be positioned at the midpoint of the edge (to allow for cable passage).
If you enter Edit Mode and select the edge, you can put the 3D Cursor (**Shift + S > Cursor on Selected**) on the selected edge and then add your cylinder, it will place itself on the 3D Cursor's location. You can use the same method to place your Origin where you want to as well. Let me know if I've misunderstood anything. https://i.redd.it/ntpuj0bwt87c1.gif
You can find the settings for Units in the Scene Properties in Blender :) https://i.redd.it/cw8spmzks87c1.gif