A curve is any path drawn through two or more defining points. A set of internal points and tangency at the endpoints define the curve.

In Style, creating good curves is the key to creating a feature with high-quality surfaces, because all surfaces are defined directly from curves.

Every point on a curve has a position, a tangent, and a curvature. The tangent determines the direction that the curve flows through the point. The tangents of internal defining points are created and maintained by Style, and you cannot change them. However, you can change the direction and length of a tangent to an endpoint.

The curvature at each point is a measure of how rapidly the curve is changing direction. A straight line has zero curvature at each point, and a circle has a constant curvature at each point that is equal to the reciprocal of the radius. Curves typically have a different curvature value at every point.