This site is amazing with its info and help. I'll get that rotary sucker
running yet.


--
Karibian

Paul, on the subject of HELP !!!! I could really use some. I am trying to
redraw my rotaty engine parts using Rhino. I have read the book but still
can't generate a tapered solid. I am using a closed (joined) line made of
arcs and straight lines. All the direction vectors point the same direction.
Extruding the "curve" with a 3 degree taper usually results in only part of
the line being extruded. In a few cases the whole line did extrude but it
was segmented not continuous. Joining the extruded polysurfaces made the
polysurface continuous, however, they would not cap into solids. The message
is "unable to cap that object" I have  tried a thin straight extrusion to
make a surface and doing a solid extrusion of that.Still a partial extrusion
or an uncapable surface. I have converted the curve to line segments, this
extrudes with a huge file size but still doesn't cap into a solid. I have
devided up the curves into smaller parts and tried that, still no joy. I
have redrawn the parts with a simplified shape (larger radius arcs) and
fewer lines and arcs with no improvement.  My only success was the
bellhousing which works if taper is in and direction is negative. This curve
fails to extrude if taper is out. All the "curves" were drawn in Rhino which
is a fully functional (for 1 year) student version. If I do straight sided
extrusions everything extrudes and caps into a solids, however that does no
good for foundary patterns which need to have draft. I keep thinking I have
to do something to the lines to prepare them for the extrusion since there
are no options on the extrusion command that help the situation.Any help
anyone an give me would really be appreciated.

george grimes

Hint. Use loft instead of extrude.
Draw 2 circles of different diameters in the front view. Drag one
away from  the other in the right view. Go into the perspective view
and choose loft. Select the first circle and then the second and press loft.
The best results happen when you get the little arrows lined up
in the front view. If you have 3 circles of different diameters
you can get a bell housing shape.

Paul Lamar