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Newbie question: How to constrain centre of square to origin. (by Gary)
I would like to centre a square around the origin (0,0) mark. It's easy to do this with a circle. It's also really easy in FreeCAD (Constraint Symmetric). I just can't work out how to do this with a square or rectangle.

Any suggestions?
Wed Mar 25 2015, 19:14:31
(no subject) (by yugami)
Put points on the middle of the top and side leg and constrain them to the middle then constrain the points H and V to the origin.

On the other hand why care about the origin?
Wed Mar 25 2015, 20:15:18
(no subject) (by whitequark)
You can do this in SolveSpace with symmetric constraint on the vertexes of the square as well.
Wed Mar 25 2015, 20:50:46
Re: How to constrain centre of square to origin. (by Gary)
@yugami: I tried to do this but couldn't get it to work. Following your comment I can now. thx. "why care about origin?" not sure. I'm used to locating my printed objects around the origin so it just seemed a logical thing to do. But I must admit that it seems a lot of work for dubious benefit.

@whitequark: well that's what I was trying to do. But I'm too much of a beginner to work out how to do it. How do I put a "symmetric constraint on the vertexes of the square"?
Thu Mar 26 2015, 20:13:43
(no subject) (by yugami)
The export will center on the object for prints etc.

The only time I cared about the origin is when I had to directly reference the coordinate grid (in older 2D systems). Since you never do that here I Just start drawing on the screen.
Thu Mar 26 2015, 20:22:57
(no subject) (by Gary)
>The export will center
I didn't know that (I'm a noob :)

Anyway it's turned into a mystery now. I'm trying to find a combination of vertexes(vertices?) of the square which will cause the square to centre around origin. I can add only constrain two vertexes around a single axis. If I try to add a second pair I get an "overconstrained" error but can't see what the problem is.

Any clues?
Thu Mar 26 2015, 20:37:56
(no subject) (by Jonathan Westhues)
Select one of the lines, and then choose Constrain -> Symmetric. The line's endpoints will be constrained to lie symmetric about the horizontal or vertical coordinate axis, whichever was closer to how the line was initially drawn.
Thu Mar 26 2015, 20:38:22
(no subject) (by Gary)
Wow! It works!

Thank you. I'll get back to my regular programming now :)
Thu Mar 26 2015, 20:40:53
(no subject) (by Jonathan Westhues)
If you place symmetric-horizontal constraints on both horizontal edges of the square, then one of the vertical constraints (that was inserted automatically when you drew a rectangle) is redundant. That's reported in the list in the browser window.

One symmetric-vertical and one symmetric-horizontal constraint will center a rectangle at the origin.
Thu Mar 26 2015, 20:44:35
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