Sketch not fully constrained

[christian_harwood]

I have a very simple sketch - a circle vertically centred on existing geometry with a fixed distance from another piece of geometry on the left. The vertical centre is accomplished with two vertically constrained construction lines which have an equal length constraint. From what I can see there should be no way for the circle to move, however the sketch is not fully constrained:

If I replace the two vertical construction lines with a single horizontally constrained construction line with a midpoint constraint the problem goes away:

Can someone help me understand why the first sketch is not fully constrained?

Thanks!

[laughingcreek]

could be a quirk/bug in the sketch solver, could be something else.  hard to say without looking at the model.

[Bunga777]

I think it is as close to a bug as you can get.

I think the reason is that although the position fixation in the Y direction is maintained by Equal of the vertical line, it is not recognized.

As a test, I set Horizontal to the seam (center of the circle) and the origin , and it is completely constrained.

I am also using it in my business and often wonder why it is not fully restrained, so I guess it is coming out in these situations.

[jhackney1972]

You did not say if you could "Drag" the circle in the first sketch?  Please attach the model.  If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it.

[Bunga777]

I tried to recreate the situation.

Even though I am trying, there are cases where I get full restraints and other cases where I don't.

Certainly the circle cannot be dragged, but it is not a black line.

The order in which I write the lines and the order in which I attach each restraint changes the result, and so far I have not found any reproducibility.

I cannot rule out the possibility that I am overlooking something serious, but I have attached a file that reproduces the situation just in case.

[whittakerdw]

I attempted to recreate this as well and what I found was that it could still be drug with all the constraints. I added the midpoint constraint on the circle and that fully constrained it to where it could no longer be drug around and turned it black.