Re: Bobcad Rhino, etc. from Digest Number 416
Posted by
Fred Smith
on 2000-03-22 07:25:30 UTC
First off I apologize for my inconsistent sigs & e-mail, we have been on the
road & our ISP has messed up many months of carefully crafted web work.
( Also for poor topic control to digest responses. Hopefully this one will
be a little better.
generated by the Picza, 3D scanner. I worked with a jewelry company about a
year & 1/2 ago to develop an interface between the Picza and either Bobcad
or Vector. This consisted of simplifying and rationalizing the scanned
output DXF file (3D faces) to contain ONLY the X-Z plane cross-sections.
Bobcad could then use these for Skin surfaces (at that time V17 was not
available so the problem was beyond Bobcad, as it requires equal numbers of
entities in V16.1). The additional problem with these kinds of files in
Bobcad, is that the skin function will not check for gouging, between the
cutter and the adjacent cross sections, or between the cutter and
concavities. ( not to be passing out rumors, but I heard that that might be
improved in an upcoming version :-). Since the passes were planar, an
offset surve was generated in the plus Z direction, and a passable surface
could then be machined. The process was not really cost effective & took
anywhere from 1-5 hours of careful, pains-taking, clicking and selecting.
As far as I know there is no other program (especially in the same price
range) that will make the cross-sectional slices that IGES2DXF makes. This
program was custom written to our specs to fullfill the geometry
requirements for the skin function in both Bobcad and Vector. It works best
with wavy surfaces, and may not properly create cross-sections across
multiple adjacent surfaces which have not been blended into a single entity.
I am not a rabid Rhino fan, but then I dislike the Autocad interface too.
In my opinion both are far too complex for use in most industrial machining
applications, and especially for Home/Hobby use. (Who has 3-6 months to
spend on learning curve & what kind of personal rewards can I get for a home
use CAD system?) That being said, I could not resist the early development
process, and was a very active beta tester. I found that the most
productive method for me was to produce 2D or 3D, wireframe drawings (and in
some cases 3D cross sections) in Bobcad or Vector, import these as the basis
of a model in Rhino, then either extrude, rotate, or otherwise modify the
original to produce the needed solid or surface. I was very disappointed
that they did not support a better 3D DXF wire frame file capability.
At the present time I have to agree with Andrew that DeskProto and Visual
Mill appear to be the best bet for interfacing with Rhino. At $1500 USD and
$3500 USD plus $800 USD price of Rhino (all list), they are a bit pricey for
the average HSM, especially when you add in the long learning curve of Rhino
and very limited 2 axis capabilities . There are a few new products coming
out within the next 2-3 months however that may change these economics.
using either the spiral out from the center or zigzag methods in Bobcad.
You could even leave large voids as islands inside the part to reduce
machining, er ... uh..., creation time, and to use less raw material for a
finished part (like honeycomb).
Because Rhino is programmable, it should be possible to generate horizontal
3D cross sections as splines. I have not attempted to do this, but with all
the users out there, someone probably has a routine to generate these, and
then save them to an IGES file.
Best Regards,
Fred Smith
IMService
imserv@...
Phone: 248-486-3600 or 800-386-1670
Fax:248-486-3698
road & our ISP has messed up many months of carefully crafted web work.
( Also for poor topic control to digest responses. Hopefully this one will
be a little better.
> Message: 19that
> Date: Wed, 22 Mar 2000 05:00:46 EST
> From: ptengin@...
> Subject: Re: Bobcad And RHino?
> Can I throw one at you since you mentioned Rhino? I'd like to know if
> there is a way to save a Rhino drawing to a DXF file that Bobcad will
> understand. I tried various ways but always get the triangular facets
> make cutting the resulting file very tough. Is there a program similar to3D faces are a problem for Bobcad. These are very similar to the files
> IGES2DXF for the .3DM files? Though I have done little with Rhino, it is
> very easy to use. Now if only I could cut from it.
generated by the Picza, 3D scanner. I worked with a jewelry company about a
year & 1/2 ago to develop an interface between the Picza and either Bobcad
or Vector. This consisted of simplifying and rationalizing the scanned
output DXF file (3D faces) to contain ONLY the X-Z plane cross-sections.
Bobcad could then use these for Skin surfaces (at that time V17 was not
available so the problem was beyond Bobcad, as it requires equal numbers of
entities in V16.1). The additional problem with these kinds of files in
Bobcad, is that the skin function will not check for gouging, between the
cutter and the adjacent cross sections, or between the cutter and
concavities. ( not to be passing out rumors, but I heard that that might be
improved in an upcoming version :-). Since the passes were planar, an
offset surve was generated in the plus Z direction, and a passable surface
could then be machined. The process was not really cost effective & took
anywhere from 1-5 hours of careful, pains-taking, clicking and selecting.
As far as I know there is no other program (especially in the same price
range) that will make the cross-sectional slices that IGES2DXF makes. This
program was custom written to our specs to fullfill the geometry
requirements for the skin function in both Bobcad and Vector. It works best
with wavy surfaces, and may not properly create cross-sections across
multiple adjacent surfaces which have not been blended into a single entity.
I am not a rabid Rhino fan, but then I dislike the Autocad interface too.
In my opinion both are far too complex for use in most industrial machining
applications, and especially for Home/Hobby use. (Who has 3-6 months to
spend on learning curve & what kind of personal rewards can I get for a home
use CAD system?) That being said, I could not resist the early development
process, and was a very active beta tester. I found that the most
productive method for me was to produce 2D or 3D, wireframe drawings (and in
some cases 3D cross sections) in Bobcad or Vector, import these as the basis
of a model in Rhino, then either extrude, rotate, or otherwise modify the
original to produce the needed solid or surface. I was very disappointed
that they did not support a better 3D DXF wire frame file capability.
At the present time I have to agree with Andrew that DeskProto and Visual
Mill appear to be the best bet for interfacing with Rhino. At $1500 USD and
$3500 USD plus $800 USD price of Rhino (all list), they are a bit pricey for
the average HSM, especially when you add in the long learning curve of Rhino
and very limited 2 axis capabilities . There are a few new products coming
out within the next 2-3 months however that may change these economics.
> Message: 20in
> Date: Tue, 21 Mar 2000 19:01:13 -0000
> From: "Ian Wright" <Ian@...>
> Subject: Re: home brew rapid prototype machines
>
> Hi Andrew,
>
> You've touched on something here which has been puzzling me for a while.
> Just how would you go about deriving the g-code for a slice of a 3D model
> Rhino. I can see how you could fairly easily get a perimeter cut but howdo
> you do the fill-in?Make your slices horizontal in the X-Y planes, and then process as a pocket,
using either the spiral out from the center or zigzag methods in Bobcad.
You could even leave large voids as islands inside the part to reduce
machining, er ... uh..., creation time, and to use less raw material for a
finished part (like honeycomb).
Because Rhino is programmable, it should be possible to generate horizontal
3D cross sections as splines. I have not attempted to do this, but with all
the users out there, someone probably has a routine to generate these, and
then save them to an IGES file.
Best Regards,
Fred Smith
IMService
imserv@...
Phone: 248-486-3600 or 800-386-1670
Fax:248-486-3698