Wednesday, November 21, 2012

Curve Handles

This entry covers the details of the types of Curve Handles.  The type of curve handle affects how the curve will be shaped with respect to the other handles.  There are four types, and we'll cover each of them and how they behave.

Before we begin, note that a single curve can have multiple curve points (hence multiple handles) and each curve point can have a different handle type.

The first handle we'll describe is the Free handle.  All curve points have three selectable points on them.  The center of the curve point, and the ends of the curve handles.  In the Free mode, the ends of the curve handles can be manipulated independent of each other.  This can product a sharp point at the curve point.




With the Align handle type (default), the two handle ends are not indenpdent, but in moving one the other will be moved so that they always stay aligned.  This ensures no sharp corners at that curve point.

The Vector handle type is a semi-auto type in that the handle points will always point at adjacent curve points.  In the image below, note how the handles of the center point are pointing directly at the curve points at the end of the curve.  Should those end curve points move, the handles of the center point will automatically follow.

The Auto handle type is a fully automated handle.  You can manipulate it's orientation, you can't manipulate the handle direction.  Essentially, the handles are governed completely by the adjacent curve points.  In this example, i moved the right curve point to the left, and the Auto curve point in the middle, automatically rotated to maintain as smooth a curve as can be achieved.

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