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Allow line end to slide along another line (by Ron Aronica)
I am new to SolveSpace and am trying to design a linkage with a sliding component. The end of one rod slides (with a coupling) along the length of another rod. One end of the rod on which the other slides pivots at a fixed point. Can I model this in SolveSpace, and if so, how? If not, what other application might allow me to do this? Thanks in advance for any help.
Sat Jan 17 2015, 16:09:48
(no subject) (by Rune)
Hi Ron, I have done something similar with success. I had to make an arrangement of arcs to simulate an interval constraint which gives you some points of no solution that you must fix manually.
Sun Jan 18 2015, 04:39:51
(no subject) (by Jonathan Westhues)
Can you post a sketch of the linkage? And have you completed the linkage tutorial,

In general, it's pretty straightforward--a line constrained to a specified length is a link, a point-coincident constraint is a pin joint, and a point-on-line constraint is a slide.

SolveSpace isn't designed for interval constraints, and attempts to fudge that are unlikely to be very satisfying. That's not generally necessary to simulate a linkage, though.
Sun Jan 18 2015, 19:04:00
(no subject) (by Ron Aronica)
Ah ha! I didn't realize that a point-on-a-line constraint is a slide. I thought that it fixed the point to the line. I will study it tomorrow, but it appears that it should do what I need. Thanks for the help Rune and Jonathan.
Tue Jan 20 2015, 03:57:32
Practical example (by Rune)
For a linkage it might be relevant to constrain it to an interval, say to model something sliding in a groove.

I have realized this by constraining to a circle as in the attached example.

Two levers (red) can act on a linkage fixed in a grove (white)
Each one is attached to the groove by a point-on-line constraint.
They can be moved by sliding the blue handle horizontally.

The upper linkage can slide off the endpoints of the grove since since the point-on-line constraints does not take the endpoints of the line into account.

The lower linkage is furthermore constraint to be horizontal with a point constraint to lie on the circle, which models the physical reality.