(and don't want to sketch another spline and add a tangent or curvature relation)
continue drawing a half finished spline
(and don't want to sketch another spline and add a tangent or curvature relation)
While there is no built-in SolidWorks functionality to do this, mathematically speaking a 2D or 3D bezier spline can be extrapolated/extended past its endpoints. To do this place and fix a number of control points on the body of the original spline (Figure 1), create a new spline with a same number of control points (Figure 2), then make it coincident will all the control points (figure 3).
SolidWorks's equation solver is not 100% correctly implemented with splines, and during this can throw erroneous over-defined errors or other strange behavior, you'll have to get creative to work around this. The exact number of fixed points you need to properly extend the spline increase with the number of control points it has. Attached is a example file.
Figure 1
Figure 2
Figure 3
Start your second spline from the end of the first spline.
Make both splines tangent.
Select the shared end point and delete it.
The splines will be merged into a single spline. The tangent handles will go away.
This works because you 'trick' the system into thinking it was once a single spline that has been split. It will work with other entities too. Split a line, select the split point and then delete it. The lines merge.
The limitation is that the last point of one entity must be the first point of the other entity.
Regards,
Andy.