SOLVESPACE -- parametric 2d/3d CAD

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error bad constrain (by normandajc)

I don't understand my error
I want both bars rotate with the same angle.
I get an error
Mon Dec 7 2015, 13:26:45, download attachment test.slvs
(no subject) (by yugami)
You stated the diameter for both then made them equal, this is too many constraints that can contratdict each other.

Delete one of the diameters
Mon Dec 7 2015, 14:20:08
(no subject) (by normandajc)
I delete one of the diameters

but I don't obtain the same angle --> test2

I resolve by this solution but I don't understand why the first solution is not good
Mon Dec 7 2015, 15:41:39, download attachment test2.slvs
(no subject) (by Jonathan Westhues)
The first solution fails because you overconstrain the diameter of the arcs, like yugami says.

I'm guessing you intended to constrain "arc length equals arc length", not "arc diameter equals arc diameter". There's no such constraint, but "arc length equals line length" with a construction line works, as attached.
Mon Dec 7 2015, 17:11:42, download attachment test-eq.slvs
(no subject) (by normandajc)
I address the test3 file
On the left, I can not get the same angle
On the right, I can get the same angle
Why figures on the left, it is impossible to obtain the same angle
Tue Dec 8 2015, 01:55:09, download attachment test3.slvs
(no subject) (by Jonathan Westhues)
What constraint are you expecting will enforce the equal angle on the left? I see only an "equal radius" constraint. Two arcs can obviously have the same radius and make different angles.

And it's sometimes helpful to do things by construction, but note that SolveSpace already has a native "equal angle" constraint; just select the four lines and choose Constrain -> Equal.
Tue Dec 8 2015, 04:49:11
test4 (by normandajc)
here's the project I did. test4
the angle A is identical to the angle B.
I do not understand why he is not to impose two arcs same radius, even arc length
Tue Dec 8 2015, 06:51:00, download attachment test4.slvs
(no subject) (by Jonathan Westhues)
I don't understand the question. It's certainly possible to constrain two arcs to have the same radius and arc length; you just need to use one additional construction line for the "arc length" part.

In my example, the quantity constrained really is the arc length, unlike your examples where you constrain a chord length. Did you look at the attachment to my first response in this thread?
Tue Dec 8 2015, 14:22:11
(no subject) (by normandajc)
I had not seen that you have sent a file test-eq.slvs .
I understand now
Thank you
Tue Dec 8 2015, 15:10:48
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