Having a basic understanding of how curvature works is important before tackling any surface project. In this section we are going to define a few terms.

G0 Continuity - Curves or Surfaces are connected but have no influence on curvature.

G1 Continuity - Curves or Surfaces are connected and have a tangency direction influence.

G2 Continuity - Curves or Surfaces are connected and have both a tangency direction influence as well as a weight/radius influence. This means the radius of curvature and the direction of curvature match at the intersection.

G3 Continuity - This isn't directly available in Fusion but this includes G2 Continuity and also includes adjusting the change in curvature as it approaches the intersection.

Inflection Point - This is a point on a complex curve where the curvature changes from convex to concave. Limiting curves or surfaces to a single inflection make them easier to define and control without introducing potential surface quality issues.