I have been using Rhino since 2000. I'm on my third version of the
software
-  4.0. I've trained on solid model software's such as solid works,
solid
edge, variations in the AutoCAD family as well as others.

IMHO it is the finest piece of software for developing designs and
taking
them through to the heavy engineering phase (not all products need
that). It
does lack material specifications so you can weight and balance
according to
multiple materials in your design (unless this feature is in the latest
version  or beta?).

There is an FEA trial version out now. I haven't looked at it but I
assume
you must be able to specify the material(s), mass etc otherwise the
loads,
bending moments etc won't mean anything.

In sum there is nothing currently on the market at any price that
approaches
the fast learning curve and development productivity of Rhino,
especially as
it relates to compound curved surfaces (a NURBS based software's
strength),
an area where solid modelers just don't cut it. You can create
solids from
all of your surfaces in Rhino with modest effort though re-blending
of the
adjoining surfaces is not one of its strengths.

Cheers,

Brian Feeney
DreamSpace Group



Brian,  Regarding combining solids in Rhino. A couple things make it
easier. First I  edit/rebuild  the curves from the default 10 points to
360 on all curves.


If a curve is particularly long I may use more
points.  You may in building curves from arcs and lines a situation
where something is slightly overlapped. If this is suspected look at it
from the side and see if there are any spikes deviating away from the
expected curve. Delete the spikes and redraw those segments.

If the
curves are on a plane I do a transform/project to C plane and delete the
originals. Then if still concerned leave one curved segment with an
adjoining straight line in place and move all the rest of the curve
away. Then useing ONLY end point snaps bring the segments back one at a
time and make a new line for the last straight segment. Use join to make
a closed curve. After the last segment joins the selection set will go
to the layer color of the first segment selected and read closed curve.
If it stays yellow you  have a lapped over or open point. This is the
clue to move the segments and bring them back.


If during the join you
get a message that there is some small difference in the end points do
you want to join them suspect a lapped line and fix that first. It will
be at the joint you are makeing. If it stays selected I push enter then
trim a .003 segment out of the curve anywhere. Select the line and where
it doesn't continue to be selected you will find the open point.Then
rebuild the curves prior to extruding or lofting them.  If you loft
curves and cap them into solids go to analyze/direction  to verify all
the direction arrows point outward.

If not flip any inward surfaces. At
this point solids should union or bullian but occasionally you get a
manifold edges failure or just solids union failed. If the two surfaces
are sort of hit and miss on contact there will be points not
intersecting but within your drawing tolerence. At this point I extrude
one of the surfaces .005 into the other one so there is complete
interference.

Some days The offending solid is made up of 60 pieces and
took two days to create. Going back to the curves seems really
distressing so I just use the group command. If you are exporting in
.stl for CNC work or just want a render of the part this works fine. If
you are doing finite element analysis you  have to actually fix your
work. If you are doing tapered extrusions watch for fillet radius-es
getting too small and becoming loops. To check for this offset your
curve  in 1/16" increments and see if any fillets converge before the
size of your intended surface.

These things seem to be unnecessary complications, however
Rhino builds complex compound surfaces and edits the crap out of them.
Other CAd programs which do not use nurbs curves simply can not do these
things. They rely more on assembling blocks into a part.  I used autocad
for a while but now Rhino is my go to program.  It will also do
mechanical design with one exception. If you have to have parametric
modeling and put elements in motion then the Catia based programs such
as solid works are prefferred.

There is an anual maintenance fee for
solid works which is higher than the retail price of Rhino4 which is
yours when you buy it for life.


Add on programs for finite element
analysis and dynamic flow are in addition to the base programs
particularly with solid works and a comprehensive set of these programs
brought the price to $14,000 when I was shopping for software.

I test
drove all of them and selected Rhino4 for $785  from "novedge.com
<http://novedge.com>"  a california based bookstore.  They were verified
by McNeel to be an authorized distributor.

george grimes

I think most of this stuff is beyond the scope of this newsletter
George and a forum should be started just for Rhino.

In other words I don't want us getting bogged down in all this.

It works use it. It will save you lots of time installing rotary
engines in oddball airplanes :)

Paul Lamar