Re: How to go from 2.5 D to real 3 D ??

> Now, here's the reason that I opine that 3D is 3D. The cutting of

a 3D arc at the lowest level is simply the issuance of a series of X-
Y-Z movement commands. That is the basis of stepping or servo
control. An arc is always cut as some minimal resolution, but still
a digital representation. If you take any 3D arc and replace it with
a series of short linear moves, at some point the actual cutting that
takes place is identical between the two methods. That is why I
contend that 3D is 3D. If a machine can cut simultaneous 3 axis
linear moves, the addition of 3D arcs does not any further enhance
the controller's capabilities.

>
> Best Regards, Fred Smith- IMService

I quite agree Fred, the end result is what counts, I've used a Roland
engraver for complex 3D modelling tasks, although it was advertised
as being only 2.5D.

Given that arcs are ultimately broken down into small linear
movements and given the increasing power and capacity of todays
computers and controllers, does anyone see the day that arcs offer
little or no real benefit ? Or do they offer another benefit that I
don't understand ?

I've been working on an Active-X module that interpolates a curved
toolpath into very small linear movements and sends these directly to
the Master5 pulse engine via Art's OCX, bypassing the need for a
large G-Code file all together, basically controling the machine
directly from the CAD program. This is a non-commercial scripted
module for 3DS MAX ver 4 so probably isn't much use to anyone here,
however, the same idea could I'm sure be used with the many free and
low cost programs that support scripting / extensions / VBA. Has
anyone taken a good look at Blender or Truespace which support Python
and why not even Corel Draw which could maybe be used as a basic
engraving program as I think it supports VBA ?

Regards,
Rab

more at http://www.rainnea.com/cnc_software.htm