
	Points and Curves: Curves

Curves are created by connecting shape points; this is analogous to a spline curve begin defined by control points. If you move a shape point, all connected curves change shape. And to get more control over the shape of a curve, you insert more points.

Figure 53. Curve Segments

Curves flow over the surface of the polymesh, tracing out the shortest distance between the shape points. If you zoom in on a curve you'll see that its made up of a number of smaller line segments, the end points of which lie on the polymesh surface (see Figure 53).

Figure 54. Curve Resolution

By default, curves are created at Mid resolution (see Figure 54). At this level you a making a trade-off between accurate curve fit and interactivity.

If you're finding that the curve drawing is slow, click on Low and the curve fitting will be about twice as fast, but half as accurate.

Figure 55. With More Segments, Closer Fit

Then once you've drawn your curves, and before you start creating patches, its probably a good idea to click on Mid or High and & (see below) to rebuild all visible curves with a more accurate fit (see Figure 55).

Figure 56. Resolution Modify Mask

In previous versions of CySlice, the accuracy of all existing visible curves was adjusted up or down whenever the resolution setting was changed. The new default behavior, enabled when the X button is on (see Figure 56), is to preserve the resolution of existing curves.
To switch back to the old behavior, enable the & button. If you enable the > button, the resolution of existing curves will only ever be increased, and with < enabled, the resolution will only ever be reduced.

Drawing Curves

To draw a curve, hold down the <Ctrl> key, then click with the left mouse button to place shape points on the polymesh; the new points and curve are drawn in red. When you've finished adding points, hit <Space>.

If you want to use an already existing point, click on it when you are drawing the new curve.

You can change the shape of a curve at any time by moving its shape points (i.e. hold down <Ctrl>, then click and drag the middle mouse button).

To insert a point into an existing curve, position the mouse pointer where you want to insert, hold down the <Ctrl> key, and click and drag the left mouse button to place and move the new point. Hit the <Space> bar unless you want to continue drawing a new curve from the inserted point.

Figure 57. Connecting Curves

To connect two curves, move one curve's end point near to one of the other curve's end points. The two points snap together and become one, and any move of that new single point will change the shape of both curves (see Figure 57).

To disable this magnetic point behavior, turn Mag off (see right side of Figure 56).
To separate two curves that you might accidentally connect together, use the Back button (see following chapter).

To delete a curve, move the mouse pointer over some part of the curve that's not near a shape point, hold down the <Shift> key, then click the right mouse button.