Re: librecad

[John Hasler <jhasler@newsguy.com>]

Gene writes:
> Thats a huge part of the problem, but theres another fence to
> jump. most of these so-called cad programs cannot generate even the
> most basic gcode.

I can see not wanting to learn even a small part of a CAD program if all
you want to do is draw a simple floor plan and then never use it again,
but doing CNC without CAD is baffling.

Freecad can produce gcode which you can inspect and modify.  The
post-processor can be customized for your particular machine.
Solvespace can also output gcode.  I have no idea how good the gcode
produced by either of these programs is because I have no way to use it.

The major feature of these CAD programs is the constraint solver, which
understands geometry and does a huge amount of work for you.  You can
draw a part with dozens of equally spaced holes, change the length of
the part, and the holes will move appropriately.  Draw an angle bracket
with a brace, change the angle, and either the bracket length or
position will adjust appropriately depending on how you constrained it.
Draw a gear specifying pitch and tooth count and the diameter will be
computed. Change the pitch or tooth count and the diameter will
change. The diameter will only change by a commensurate amount: no need
for you to calculate allowable dimensions (unless you want
fractional-tooth gears).

You can also do assemblies and specify constraints between assemblies so
that a change in one part will cause appropriate changes to others.
Interferences that would result in two objects occupying the same space
won't happen.  You can animate assemblies and watch the machine run.  No
more making cardboard models of linkages and then having to stick to the
tested ratios.

There are also lots of contributed macros and add-on toolbenches for
Freecad.

-- 
John Hasler 
jhasler@newsguy.com
Elmwood, WI USA