Hi,

I am trying to import all type of supported sufaces using OpenNURBS. While working on surfaces of Revolution I found that paramterization along the angular parameter (U in most cases) is not expressed in a standar way. For example, I have created two brep object that each one represents a torus. The first one was generated via the “Torus” command and the second one by revolving a circle along the z axis. The U paramterization is expressed in radians for the first object and in length for the second one as follows:

**Torus via “Torus” command**

Surface of Revolution

U = angular parameter, V = curve parameter

"U": Periodic (0 <= U <= 6.28319)

“V”: Periodic (0 <= V <= 29.2412)

**Manually created torus**

Surface of Revolution

U = angular parameter, V = curve parameter

"U": Periodic (0 <= U <= 55.9316)

“V”: Periodic (0 <= V <= 18.4956)

Since for a surface of Revolution parameterization along U can be expressed in different ways (not only for torus), is there an explanation on this? Also, is there any function of ON_RevSurface class that returns if it is expressed in radians or lenth?