【转帖】how to extrude an opened loops of curve segments
 

how to extrude an opened loops of curve segments?
how to extrude an opened loops of curve segments?
for closed loops of curve segments, we can create a region from odrxobjectptrarray of curves, create an oddb3dsolid entity to extrude the region. we cannot create a region from an opened loops of curve segments. how can we extrude an opened loops of curve segments? please give me some hints or sample codes. i just wonder if we can use oddbextrudedsurface, but i do not know how to use it.
thanks.
oddb3dsolid can't be created by extruding non-closed set of curves.
oddbextruded surface method for creating it from an oddbentity is not implemented yet.
but you can create a 2d entity like polyline or arc and set non-zero thickness to it (extrude along normal vector).
sergey slezkin
thanks for the reply.
extrusion works with polyline and arc, but it does not work with an ellipse. why does an ellipse not have a thickness? line, polyline, arc, and cirlce all have a thickness.
ellipse and spline do not have thickness because these entities were desined so by autodesk. i only can suppose why:
thickness was introduced long ago when autocad was not using acis modeler.
entities introduced later do not have thickness because acis can be used to represent 3d objects.
sergey slezkin