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