How this family works?

[smm.144]

I could not figure it out why by moving vertical reference plane the whole model stretches?
I renamed the reference plane to magic!

[smm.144]

Any ideas?!
I tried removing all constrains but can't figure it out what makes the model stretch.
Even model lines move with the reference plane..
It would be very handy if I learn how to do this..

[patricks]

There is a short model line at the upper right and lower left with the Web Offset parameter defining their length. Then there's a diagonal model line spanning between those two short lines. The actual 3D geometry uses sweeps with paths defined by picking the model lines. That's how the 3D geometry stretches when the "magic" ref plane moves. The diagonal model line stays attached to the two short lines, and the 3D geometry follows the model lines.

[smm.144]

Thanks Patricks for the answer.
But I have one more question, there is another sweep connected to the member you mentioned; And it's path is not even connected to the magic. How does it move with reference plane?(How it is constrained to the plane?)
Thank you very much.

[patricks]

That other piece is a sweep with a path using 3D pick path from the other member's edge. So in 3D if you edit that sweep, and then edit path, you'll see the path is attached to the edge of the first diagonal member.

As for the length of the path, I guess the Automatic Sketch Dimensions (normally hidden) keeps the end points of the path a constant distance from the ends of the diagonal member. I probably would have put actual locked dimensions to each end point of the sweep path, but that's just me.

[smm.144]

That other piece is a sweep with a path using 3D pick path from the other member's edge..

Thanks Patricks,
I did not notice that before you mention it.
About the length of the path, I think it is just constant and there is no dimension.
Thanks again.

[patricks]

It's not constant. If you drag the vertical ref plane left or right, you'll see that the endpoints of that sweep stay in the same place relative to the ends of the diagonal member. The sweep length adjusts so that the ends stay in the same place.

And actually I just noticed that if you use Pick Edges to define a sweep path, you cannot place any dimensions in sketch mode. So I do not know what's keeping the ends of that sweep constrained to a fixed distance from the diagonal member end points.