Most of the constraints in Alibre constrain in a manner limited to the specific constraint dimension. If the end of a rod is constraint to align with the X-Y plane, or a planar surface of a part, it can move any where within that plane. Or if a rod is aligned with an axis, it can freely move anywhere on that axis. The "Tangent" constraint is unique in that it seems to constrain in multiple dimensions. This is a problem. For instance, I have some client work, and I needed to constrain a piece of structural pipe to lay against a piece of 5 x 5 x 3/8" angle. So of course I used tangent (I suppose I could have used align, with an offset). When I completed the tangent command, the piece of pipe was aligned tangent, bit was ALSO constrained, somehow, so that it could only move axially. It was not possible to move it closer to the final location. I expect that it would still respond to actual further constraints, but it could not be dragged. (In this case, I only needed it to look OK for an illustration, so I did not want to go through the hassle of establishing more planes to locate the thing.) I find this behavior of the tangent constraint to be anomalous, as well as extremely annoying. It create problems in workflow, since tangent must not be applied until last. The most irritating thing is that not every part behaves like that. Some are fine. But, cylindrical parts are particularly subject to it. I wonder if it is possible to fix it so that it behaves the same as the bulk of (if not all) other constraints, in limiting ONLY to its actual constraining action. The goal is to allow a tangent constrained part to be moved around "manually" in any way possible without violating the tangent constraint itself (or that combined with any other concurrent constraint). Is that possible? If so, can this be put on the list for an upcoming service pack or release? If not, why not?