You can't. ArchiCAD doesn't support NURBS, which basically interpolates surfaces from limited points. So, to look close to the original NURBS object, you'll have to have lots of polygons. Converting to a Morph and smothing can help permit fewer polygons though.
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB
