What is A Class Surfacing

A-Class surfacing is defined as these two major points
1 lightly created geometry and that the geometry is built correctly.
2 light reflections are reflecting in a desirable way. i.e. if g2 is required then the light reflects in a g2 way.

A Class surfaceses are those aesthetic free form surfaces, which are visible to us (interior/exterior), having an optimal aesthetic shape and high surface quality.

Mathematically class A surface are those surfaces which are curvature continuous while providing the simplest mathematical representation needed for the desired shape/form and does not have any undesirable waviness. < this waviness is found with a goussian anaylisys.

Curvature continuity: It is the continuity between the surfaces sharing the same boundary. Curvature continuity means that at each point of each surface along the common boundary has the same radius of curvature.

+Compare G0
positional conections. Not tangen but touching.

+Compare G1
simply tangent. The surfaces in this example are tangent, the curve plot is not tangent. This line can not be broken down to a more simple curve therefore it is not curvature continuous or G2. You can not take an integral at the intersection of the curve as it crosses to the other surface.

+G2
curvature continuous. When a curve plot is tangent. The equation of the curve plot can be broken down into a more simple curve by taking an integral. ie. calculus

five ways to determine g2 continuity.
1. Evaluate with your eyes the light reflections
2. Evaluate the math using Calculus (if you can take an inergral at a curve that crosses a surface intersection then there might be g2 continuity)
3. Look at the curve plot in either Pro/E or Alias
4. Spans or CV's line up in Alias
5. zebra stripes

Some people will use a Gaussian analysis incorrectly. In this tool G does refer to that specific mathematician however the standard Gaussian analysis refers to concave vs convex. ie. when light reflects back to they eye.




A class surfacing workshop by Design engine education in Chicago http://www.proetools.com/courses/isdx/level7.htm