Re: More CAF...

Hi Arne,

There are programs about for Windows which behave as you suggest below,
indeed, most CAD programs can be made to act similarly if you predraw
'standard' objects as 'blocks'. The difficulty is that no two jobs ever
seem to require the same size bits. In a decent CAD package like Autocad
or Rhino drawing the various parts, even in 3D is very easy once you get
into the correct thought processes. The majority of people who have
difficulty with CAD do so because they try to think of it as drawing on
paper - a set of lines, whereas you need to think rather in terms of
'made parts' and do a mental analysis of the structure you wish to
portray before committing it to the computer. This may sound complex but
it is really quite easy and simply means that, if you want to draw a
turned shaft you think of it as a number of joined cylinders rather than
as a series of parallel lines. Almost all CAD programs use the same set
of commands and have various options to make life easier, thus, you can
draw a circle by specifying either its centre and radius or diameter,
the two ends of its diameter, or just three points on its circumference
where you want it to touch other parts. This kind of function is useful
in design as you can draw things to fit and then measure them
afterwards. Actually drawing this way is much quicker than importing
'standard' objects and the altering them to suit and fits in easier with
the 'text' method of drawing which is normal - i.e. you specify most
dimensions as 'command line' entries and only use the mouse for
selecting menu items or snap points. These snap points are also a very
useful feature of CAD programs and enable you to join sections of
objects to others exactly or specify the size of objects by exact
reference to others. There is little to choose between Autocad and Rhino
( except in cost!!! ) and both have their good and bad points - Rhino
had better rendering capabilities than Autocad but suffers from the need
to type commands such as 'line' and 'circe' in full where Autocad simply
understands 'l' and 'c' for these. The only CAD program I know which
combines both CAD and CAM and produces a G-code file is BobCAD but the
CAD part of this is a bit limited for anything other than 'routine'
work.

Ian

"Arne Chr. Jorgensen" wrote:

> Imagine you have a desktop like windows, with the icons laying
> around. Ok, I would like to turn an axle, with several different
> diameters. I pick up a cylinder shape from the desk top, - and
> while I do that - I drag it out to the length and diameter where I
> would like a bearing to sit. But the axle, needs more. I pick up
> the cylinder icon again, - repeat what I did, and just attach it.
> Then I need some threads, and .... when I am done, - I pick up a
> raw material icon, shape it as an envelope around the object. I pick
> up a machine center icon, and a drawing icon - click them, - for
> printout and machining. Done. ( maybe it should spit out the invoice
> too, while it's at it ! )
> I don't think that should be a difficult program to make, but then
> what about other shapes ? ( hmm... )

Best wishes

Ian

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Ian W. Wright LBHI
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Bandmaster and Euphonium player of the Hathersage Brass Band. UK.
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