Re: Direction follower ?

Hi Bruno,

you are right on the money here.

now if there was a program that incorporated this into the basics I'd
be testing it in short order.

Dave

--- In CAD_CAM_EDM_DRO@y..., "bschwand" <bschwand@y...> wrote:
> This is basically a geometry problem; what you need to do, is keep
the
> cutter tangent to the curve defined by the cutting path.
>
> If the pivot of the cutter is exactly above the cutter i.e. the
cutter
> is not offset (unlike a ball caster), you can approximate the
tangent
> of the curve as the line between two points of the curve, infinitely
> close together, on each side of the cutting point. That tangent is
the
> direction the cutter should take, for each point along the curve.
>
> If the pivot point is offset from the actual cutting point, you
follow
> the same process described above, and in addition simply move the
> cutter position along the tangent found, by the appropriate offset
> amount.
>
> Having an offset cutter would allow you to not need an additonal
axis
> (the cutter angle) to control, as the movement of the cutter would
> define the angle needed.
>
> Is this of any help ? Let me know if this is not clear. I am bad at
> explaining things...
>
> You will have to write extra code, but depending on the
representation
> of your initial toolpath, it could be done in a simple perl script
> that takes your toolpath as input and massages it in the correct
> toolpath.
>
> For any geometric problem of this type, I highly recomment to use
and
> experiment with IRIT ( http://www.cs.technion.ac.il/~irit/
> (Open-source, all platforms)) a 3D modeller mainly oriented toward
> geometric operations. It can help you visualize the problem, and
> compute the solution. IRIT may be overkill since it is research/math
> oriented, and the learning curve is steep, but you can do amazing
> things with it.
>
> I am currently working on methods to automate toolpath creation
from a
> given volume with IRIT. Yes, I know software exists to do that, but
it
> is not open-source, and I like to do it since I can :-)
>
> bruno
>