4 Replies Latest reply on Sep 20, 2012 12:01 PM by M. O

    How to set a spline handle perpendicular to a plane

    M. O

      Hi there.  I'm trying to draw a 3D spline between 2 bodies.  I start the spline on a face on body#1, and end the spline on a face on body#2.  The only constraints that I want to define are that the spline ends start perpendicular to the faces, but I can't figure out how to do that.  I tried dragging the handles, but that isn't very exact.  I'm sure I'm missing something simple.  If someone could steer me in the right direction, I'd appreciate it.  Thanks.

       

      Michael

        • Re: How to set a spline handle perpendicular to a plane
          Steve Ostrovsky

          You could always draw in centerlines at the spline ends and then make your handles collinear. I'm going off memory here so it might be another relation, I've used centerlines to help control spline handles before.

          • Re: How to set a spline handle perpendicular to a plane
            Harold Lakoduk

            Michael,

             

            Steve's on the right track with the centerlines or construction lines.

             

            I would place an On Plane constraint between the end points of the spline and the face of the body. Sketch construction lines from the end points of the spline and apply a perpendicular constraint between the construction line and the face. Finally apply a Tangent constraint between the spline and the construction line.

            You may have to use the spline handle to drag the spline to approximate the tangent condition before applying the constraint.

             

            I'm assuming that you are setting up some guide curves for a loft so you may need to make the spline coincedent to an edge on the body face; I get an errror message if the guide curve doesn't start and stop on an edge.

              • Re: How to set a spline handle perpendicular to a plane
                Steve Ostrovsky

                There you go - nice detailed answer. First time answering through my Dolphin Broswer on my Droid RAZR...

                 

                Here's a picture (If I can the darn thing to load) - Centerline is Perendicular to the highlighted face and then Collinear to the spline handle - this is just to show an example of a way to use a centerline to help guide the spline handle or spline itself.

                 

                Spline Control.JPG

                • Re: How to set a spline handle perpendicular to a plane
                  M. O

                  Thanks so much to both you and Steve for the quick, detailed answers.  It turned out even easier, because the bodies were both cylinders so there were already temporary axes in the correct orientation.  I just had to constrain the spline tangent to the axes.  I was never given a colinear option, which is what I had been looking for and why I was stuck.  Not sure why I didn't think of tangent - seems obvious now.

                   

                  Thanks again!

                   

                  Michael