DefinitionA <CANONICALLY PARAMETERISED SURFACE OF LINEAR EXTRUSION> is a <PARAMETERISED OBJECT WITH UNIT LENGTH> and a <PARAMETERISED SURFACE> and a <SURFACE OF LINEAR EXTRUSION>; it has the canonical parameterisation for a surface of linear extrusion as follows: σ(u,v) = λ(u) + v.l.V As defined in ISO 15926 Part 3 Section 4.6.3.15