6 Replies Latest reply on Jan 16, 2014 2:36 PM by E. P

    3D Sketch dimensions flipping around?

    E. P

      So this happens sometimes when I've got a 3D sketch dimensioned to another part in an assembly. 

       

      I'll dimension a parts 3D sketch to another part in the assembly.  All's well until I change overall assembly dimensions at the top level, and then the dimension flips around.

       

      This turns a .625" clearance into a .625"interference.  Not good...

       

      Ideas?

      dimensionflip2.JPGdimensionflip1.JPG

        • Re: 3D Sketch dimensions flipping around?
          Jeremy Feist

          are you selecting an edge, face, or other of that other part to create the dimension? I would avoid any 2D element (edges, axis, sketched lines), as the direction "from" one of those in a 3D space is ill-defined.

            • Re: 3D Sketch dimensions flipping around?
              E. P

              I'm selecting the greyed, sketched construction line of the other 3D bounding box sketch in the pics and assembly. 

               

              The coincident point of the active sketch (by the .625 dimension above) is "on plane" to a plane defined by the 3D box sketch mentioned above.

               

              I agree that the issue likely has to do with that vagueness of 3D space.

               

              Here's one work around that usually holds up; it's a small line that is coincident to the greyed sketch, and collinear with the active sketch line.  This "locks" the position of the dimension in 3D space.

               

              dimensionflip3.JPG

               

              Any ideas on a quicker/better way to go?  I like to avoid selecting faces of parts, as they often change/get deleted, but the 3D sketch bounding box never goes away.