Make curves dynamic

You can make any curve a dynamic (hair) curve. When making curves dynamic keep in mind that hair stiffness is defined per CV and is dependant on the number of CVs in the simulating hair. By default this matches the number of CVs in the start curve. The Sample Density on the follicle can be used to scale this number. If the Sample Density is 2.0 then the simulating (and output curve) will have twice as many CVs and be half as stiff.

Stretch Resistance and Bend Resistance are proportional to the density of CVs on the curve. So it can be more efficient to use as few CVs as possible on the dynamic curves and then smooth the output ( subsegments on the hair system ).

In some cases, you might want to create a floppy rope with many CVs that is not too stretchy. You can do this is by increasing Substeps and Stretch Resistance, while decreasing Bend Resistance.

For sample scenarios using dynamic curves, including images and workflows, see Dynamic spline IK chain illustrated using a butterfly tail.

To set the Make Curves Dynamic options

1. Select nHair > Make Selected Curves Dynamic> .

   The Make Curves Dynamic Options window appears. For descriptions of the options, see nHair > Make Selected Curves Dynamic.

2. Set the Make Curves Dynamic Options as desired.
3. Do one of the following:
   • Click Make Curves Dynamic to turn the selected curves into dynamic hair curves. The Make Curves Dynamic Options window closes.
   • Click Apply to turn the selected curves into dynamic hair curves. The Make Curves Dynamic Options window remains open.
   • Click Close to cancel the Make Selected Curves Dynamic operation and close the Make Curves Dynamic Options window.

To make a curve dynamic

1. Select the NURBS curves you want to make dynamic.
2. (Optional) Shift-select the surface or hair system to which you want to attach or assign the curve when it is made dynamic.
3. Select nHair > Make Selected Curves Dynamic.

   The selected curves are made dynamic hair curves.

   If you selected a hair system in addition to the curves, then the dynamic curves are assigned to that hair system.

   If you selected a surface in addition to the curves and the Attach Curves to Selected Surface option was on, then the dynamic curves attach to the selected surface.

4. (Optional) Customize your dynamic curves by modifying the attributes in their follicleShape nodes. For descriptions of these attributes, see follicleShape.
   Tip

   The Damp value can be used to relax oscillating curves on non-straight hair.