Which vertex type is not constrained to lie on the surface and has a rational weight that affects its influence on the area, abbreviated as CV?

Which vertex type is not constrained to lie on the surface and has a rational weight that affects its influence on the area, abbreviated as CV?

• A. Surface point
• B. Control Vertex
• C. Normal
• D. EM Face

Answer: (B)

In spline and NURBS modeling, you work with vertices that shape the geometry, and these can behave quite differently. A Control Vertex is the point that defines and influences the curve or surface without having to sit exactly on the surface itself. In rational (weighted) representations, each control vertex has a weight that scales its influence. The surface is formed from these weighted points, so changing the weight changes how strongly that vertex pulls the surface toward it, effectively altering the resulting shape and area influenced by that vertex. This is why the described vertex type fits: it’s not constrained to lie on the surface, and it carries a rational weight that directly affects how much it influences the surface area. A surface point, by contrast, must lie on the surface; a Normal is a direction vector, not a vertex with weight; and EM Face is a face element, not a weighted vertex type. Therefore, the correct concept is the Control Vertex.

In spline and NURBS modeling, you work with vertices that shape the geometry, and these can behave quite differently. A Control Vertex is the point that defines and influences the curve or surface without having to sit exactly on the surface itself. In rational (weighted) representations, each control vertex has a weight that scales its influence. The surface is formed from these weighted points, so changing the weight changes how strongly that vertex pulls the surface toward it, effectively altering the resulting shape and area influenced by that vertex.

This is why the described vertex type fits: it’s not constrained to lie on the surface, and it carries a rational weight that directly affects how much it influences the surface area. A surface point, by contrast, must lie on the surface; a Normal is a direction vector, not a vertex with weight; and EM Face is a face element, not a weighted vertex type. Therefore, the correct concept is the Control Vertex.