Posted by georgesbasement on Aug 09, 2017; 4:20pm
URL: https://forum.librecad.org/Rotating-tabs-inconsistencies-tp5715190.html

Here I am, faced with a bunch of entities to cut out of a metal plate by either of two techniques: water jet cutting or laser cutting. In either situation the plate is held by the edges. If the process cuts all the way around any one object, it will fall out of the hole and down into what amounts to oblivion, that is, it will likely get lost.

Therefore, I have to leave an uncut tab on the periphery of every object so that it will remain attached to the plate.

So far, I have managed to create a series of blocks, each one depicting a tab pointing in a useful direction. This effort is not without its problems. The main one is that when I attempt to open and modify a tab and then create another named tab from it, thereby being given the opportunity to name the new tab, I find that after I have closed what I think is the new tab, I find that I have modified both tabs and now have two identical tabs with different names.

How to I turn the original tab back the way it was originally pointing ? I find that both "Move and Rotate" and "Mirror" produce unpredictable outcomes. Sometimes "Mirror" rotates my tab by an uneven multiple of ninety degrees. I don't know what is the meaning of "angle" in this context - on an absolute polar-coordinate system or just relative, applied to the object's desired motion.

What's worse, now I've discovered that four out of six versions of this tab have gone blank. They will have to be re-created ... but I have lost all confidence in how to accomplish that. I need six more positions on my compass, 45 degrees apart.

On top of that, I find that editing a tab (from the list of tabs) changes all instances of that tab that have been put in my drawing, so I have to create and finalize all the desired tabs before ever starting to use them in my drawing.

Best regards,
georgesbasement