Hi guys

I just found this bug in Luke's sketcher branch while testing his new work. I just checked and the bug is also in SF git/Master.

Have a look at this file, it is two lines on a circle. The way it is constrained, you can drag the "triangle" in circles around the circle, which partly works.

1) if you drag the "triangle" around the circle it goes most of the way around and then suddenly flips to the other side.... then if you keep the mouse pointer going around the circle, the triangle suddenly flips back again.

2) If you select the apex of the "triangle" and then set either one horizontal distance or one vertical distance constraint it says the sketch is fully constrained, which it is not. If you look at the screen shots attached you will see the two valid possible out comes for a vertical distance constraint. The error is the same type of thing if you set horizontal distance constraint

3) if you set lock constraint on the apex it complains of being over constrained ....which might or might not be the case.

4) this point happened the first two times I tried to set vertical distance constraint but after closing and reopening the file, I have not yet managed to get it to repeat. I will test further on this point. When the apex was one the right hand position of the two possible outcomes for vertical constraint on the apex, it inserted the correct vertical value but flipped the triangle over to the lower left hand side (the second possible outcome for that vertical constraint value)

I am wondering if this is a problem with how "length along line constraint" works? I might well be talking complete crap, but I was wondering if the horizontal and vertical distant constraint is working of the x and y value of the length along the line constraint rather than truly working on its length. If so that could explain what is going on.

Manits link

https://sourceforge.net/apps/mantisbt/f ... php?id=754