thanks, i tried a new part and it worked. the problem I seem to have is when designing something using sketches and make changes I run into lots of trouble with sketches, not being able to find the over-constrained part. so in frustration I start over and sometimes it works and sometimes I go a completely different direction
I was having trouble drawing the dark green part. I wanted to make a snap piece to go on 1/2" pvc.
instead of circles i used arcs and offset.
yes, well the 3rd circle should not have been highlighted. in the attached file I was trying to do reversed arcs to make the snap, I thought 2 circles, use the tangent then trim what I didn't want, seemed simple to do until it was over-constrained, then it is like I can't do anything, so i gave up and tried plan B, but I did want to know how to constrain 2 circles, so when i tried the new part, it worked like I thought it should, but I certainly agree with your question "Could that be confusing the constraint system?"Did you sketch the two circles one on top of the other? There may be an inferred constraint involved. Also in the image it looks like three circles are highlighted. Could that be confusing the constraint system?
That sounds like a question for Alibre Support or Development. Unless there is an inferred constraint between the circle and the line.Why does using the lock constraint on an unrelated reference figure kill my ability to constrain the circles concentric to each other? Is that normal?
David, have you though of using the Thin Extrude? You won't have such a complex sketch if you do, I've worked one out with three tangent arcs.I was trying to do reversed arcs to make the snap,
thanks, i tried a new part and it worked. the problem I seem to have is when designing something using sketches and make changes I run into lots of trouble with sketches, not being able to find the over-constrained part. so in frustration I start over and sometimes it works and sometimes I go a completely different direction
I was having trouble drawing the dark green part. I wanted to make a snap piece to go on 1/2" pvc.
instead of circles i used arcs and offset.
ok, thanks. I opened a new part sketched a circle at .85 and created another circle, selected the centerpoint to create a circle at 1.05. select the center and drag both wherever I want. I opened the file I was having trouble with and did the exact same thing on an existing sketch (the pkg file is uploaded to the thread) and the attached pic shows the result of trying to drag. I just couldn't figure out what I was doing wrong. also I have the inferred constraints all un-checked and always have, not sure if that makes a difference. I am just trying to learn here.If you begin the node of a circle (or any sketch figure) on the node of another sketch figure, the nodes are locked together (through an inferred Coincident constraint). Since we don't want dozens of coincident constraints to litter the canvas for every node pair, we don't show those. However, if you construct the circle like this, the centerpoints are already coincident. I think in the circle node case, the Concentric constraint is what actually gets made first, instead of the coincident constraint.
What you may have also done is drag and drop the circle's centerpoint node (or any node of any figure) on top of another node (in this case the 2nd circle's centerpoint) and it will make a hidden coincident constraint.
Since this hidden coincident constraint already exists, making the circles concentric will overdefine them since they are already concentric. Since you have dimensions, especially different dimensions, on the circles, a co-radial constraint does not make sense. CoRadial is typically mode useful for ar