I got all my autocad drawings redrawen pretty much from scratch
 into Rhino over the last three weeks. Basically the parts are a flat plate
 with an external shape for the part, from which small solids are subtracted
 for water manifolds, lightening, porting of intake and exhaust,stationary
 gear mounting, "O" ring lands and bolt holes.

     I have the pieces located within the plate part but am having trouble
 subtracting them from the main plate using the "solids difference" command.
 Some subtract as expected, however about half of them return an error
 message "boolian difference failed"

        I did a test run with the pieces as polysurfaces and had similar
 problems. I have since converted them to solids with the  "create solid"
 command which  appeared to work 100% of the time. I have eleven various
 parts for  foundary patterns and another eleven pieces for finished parts.
 The engine requires six components, the rest are for differing motor
 mounts,
 water pumps, and a connector bellhousing to connect two engines end to end.

        I also have difficulty with the "solids union" command which
 returns  "solids union failed"with the larger parts such as the sidewall of
 the bellhousing and the flange. Since some sections will subtract from
 these
 larger pieces and some similarly shaped sections will not, it appears that
 the larger parts may not be the problem. All the parts have a 3 degree
 taper
 on the edges for use as foundary patterns.

       The various pieces were constructed with a bottom surface a side
 wall and a top surface connected with the join command. The "cap planer
 holes" command doesn't seem to work on complex shapes, just circles and
 rectangles. The "surface from planer curves" command does work indicating
 the curves (outlines) are indeed in the same plane.

    Any help anyone can offer would be greatly appreciated particularly with
 the boolian commands. Also something which would indicate what error caused
 the error messages would be helpful.  The manual shows how to apply the
 commands but lists very little help on what to do when they fail to work.
 Virtually  the same documentation problems as Autocad.

 george grimes

 I want to see some renderings George :)

 Paul Lamar

Paul, I would sure like to get your input on this engine and will send the
JPG output just as soon as I can figure out why the difference command isn't
working. I did a JPG of another part and know how to save a render to that
format. Without the  parts subtracted out all that would render is the
external shape sort of like something with a Christmas cookie cutter shaped
like a side housing.
       Yesterday my new desktop quit, something to do with windows system
check deciding to shut everything down. I did the clean all the cable
connections and t ran another few minutes. Now all I have is the BIOS
screen. I don't have a lot of spares for this newer stuff so I will send it
off -again-for the third time.
     If it stops raining I can get the electric service connected to the
hanger which is pretty much wired up except for the larger machine tools.I
should be getting the large format printer operating, but I am just about
tired of computer problems and have no reason to expect that plugging it
into the wall will get me airframe drawings in full scale.

george grimes

The difference command is very picky. You want to make sure both
objects are truly solid. Choose "solid" and scroll down to "cap planer
holes". That usually does the trick. Practice with simple shapes
such as two blocks of different size. For complex shapes
choose: analyzemass propertiesvolume and it will tell you where
you are going wrong.


Go to: http://www.frys.com/
choose: electronic components>computer components>mother boards>intel
>view all Intel boards. Scroll down to Item # 6033738

This is a brand new ITX mother board that will fit in any old case.
That INCLUDES the Atom processor for $80. << Some of the memory you now
have may fit. If you buy a mother board, Fry's will sell you
MS Xp for about half off. Around $100. You may need a SATA drive
for about 500 gig for about another $100. Most old keyboards will work
as well as VGA monitors you now have.

They also have a complete Acer system using the Atom, a 160 G drive
screen, 1 Gb memory,  XP and keyboard for $200.

This is a lot of bang for the buck in computers.

Paul Lamar