Class A Part 2/2 - what is needed, and how to get there 

The blend surface created with the VSR tools is Class A, while the one being created by Rhino is not. Class A = G2 (when wanted), only the really needed amount of control points, smooth running light lines.

VirtualShapeResearch Whatever Tool you use what I can see in your video that is not a Class-A surface. Thank you for the Class-A explanation. But A really Class-A is MUSH more than that ;)

+Combo Jerman then why don't you explain it, at least in a nutshell?

Class-A surface usually means a blend, or patch or multiple blends and patches which consist of Single Span surfaces (no knots are allowed). Thus and usually most of the blend surfaces are of a degree 5 in both directions (U and V) but sometimes degree 6 and 7 are required for more detail and seamless flow between the patches. In all cases they have to be single spans = minimum CV (control vertices, control points). Signle spans usually translate and export later to mesh or other 3D formats without problems. Nowadays computers are very fast and powerful and single spans do not have such an impact but lead to more work and patching and CV tweaking to match perfectly. On the other hand surfaces and curves with more knots mean more CVs and more hard work tweaking them (if necessary for the perfect blend). All depends on the degree of the curves that will form the surface blend or patch. Sometimes to describe a specific curve the designer might need degree 7+ curve (8 CVs in a single span). Usually degree 4 is perfectly enough (for self smooth G2 continuity on the knots) with the cost of having 2 knots. Degree 3 is also fine but the blends might result in G1 continuity only (depends on the specific case). T-splines usually have degree 3 but their knots in a T-conection or Y-conection or Star-conection will have only G1 (just in the knot connection). Outside they will have G2 by default. Single span surfaces are easy to match but they have to be chosen cleverly otherwise could lead into dealing with patches into patches into patches. Usually when converting T-splines to NURBS you can see the multitude of patches needed. Thus without T-splines cleverly positioned single spans are preferred. None will make fun of you if you use 2 or 3 knot blend surface if you'd like to save time, as long as G2 is achieved at the edges and no undesired deformations have occurred in other areas of the aforementioned multi-span surface. Sometimes multi-spine surfaces may get converted into denser meshes because of the denser CVs. Just choose a degree 3 or at the very extreme degree 4 curves (to create blends) when multi-spans are unavoidable.