spline help

[Don9of11]

I am trying to create a spline tangent to two curves and passing through 3 points. Having selected the three spline points I hit enter to select the start tangent, so I bring the spline up along the upper radius until the intelligent thing reads tangent and there I click enter then proceed to the lower radius until the intelligent thing reads tangent again and click enter but the spline never connects to the tangent points.

So my question is this - if DS can detect the tangent point along the sweeps (radius) why doesn't it connect the spline? Now if I knew where the tangent point was on the sweeps ahead of time I would trim them so the spline has an end point to connect to but I don't know where the tangent points are! So what should I do. I hate to give up using DS, it's nice program.

 

[laik]

Hi,
Spline curve is complicated by describing a precise mathematical functions. You can not extend the spline without added another point (s). DraftSight is not designed for handling with spline. Does not contain the appropriate commands. SolidWorks is a suitable for example. It contains in the SKETCH mode series of commands for editing SPLINE curves.
Another programs (Creo, Catia, Inventor) maybe contains commands for editing spline too. For example you can view the webpage about spline

http://www.cs.mtu.edu/~shene/COURSES/cs3621/NOTES/notes.html

or

http://ibiblio.org/e-notes/Splines/Intro.htm.

You can see short example with manipulating with spline in SolidWorks sketch.