i store my surface control points internally in microns. Is there a way to scale/convert it to millimeters? I knot i just can scale all the control points with 0.001, but is there a nicer way?
When i export the surface i use an ONX_Model
model.m_settings.m_ModelUnitsAndTolerances.m_unit_system = ON::millimeters;
There i can set the unit system, but it actually has no effect on the surface!
(Menno Deij - van Rijswijk)
No, the unit system is meta information, and has nothing to do with the numerical representation of geometry.
If you change the unit system of the model and you want you geometry to scale with the change, then this is something you will need to do on your own - the openNURBS toolkit will not do this for you.
const double scale = ON::UnitScale(ON::microns, ON::millimeters);
// TODO: transform objects...