Helical Solid

[jakewells]

I'm looking to model a spring in PowerNURBS where the coil spacing tightens at the ends of the spring.

Using max splines, I would accomplish this using the 'bias' option (see below). Is there any workaround for doing this in PowerNurbs?

Also, is there a way to taper the radius of a helix along its axis?

[PiXeL_MoNKeY]

You can use the Helix to do what you want.
1) Create a Helix Shape.
2) Add Edit Spline.
3) Select the Curve in Spline, Right-Click > Tools 1 > Curve.
4) Create a Pwr_Tube.
5) Select the Helix.
6) Optional: Go to the Pwr_CmpSkt SubOperand > Curve Reconstruction > Re-Interpolate > Num Samples: 20
7) Enable Radius from Deriv. Surface. You can now use the tangency on the Pwr_CmpSkt to define the radius of the tube.

Hope that helps,
-Eric

[jakewells]

That's fantastic ... thank you!