Re: RP definition

From: Delft Spline Systems (
Date: Tue Feb 06 2001 - 10:53:30 EET

At 06/02/2001, Ian Gibson wrote:
>So in summary, you can use RP machinery, CNC machines, or even a hammer and
>chisel to achieve rapid prototyping, so long as you are using the quickest
>method available to achieve your objective. With Autofab, you must be using
>an automated method. If you are using RP machinery, you are using a
>layer-based technology.

Dear Ian,

You surely do propose a smart solution, a sort of workaround double definition
to satisfy all parties involved. Still in my feeling these two solutions
involve a
serious twist that makes them in fact invalid. For me it is obvious that RP
RP machines do have a 1 to 1 relationship. So an RP machine is a machine to
do RP, and to do RP you need an RP machine. Just as it is for any other
technology like drilling, grinding, etc etc.

In your definition of Rapid Prototyping you ask
>Why should we start with a computer-generated model?
This is a valid question, as the limitation to automatic processes and
3D CAD data is indeed arbitrary. For instance a skilled crafsman (or in your
words sculptor) who carves a foam model from manual sketch within
10 minutes: why should not this be called Rapid Prototyping ? It is both
Rapid and it is Prototyping isn't it ?

Still in my opinion it does make sense to limit the definition to
Automatic and 3D CAD data, as limitation does make it a useable
definition of a certain type of activity, of a certain designer's need.

Then of course the next question is: if limitation is so useful,
why not limit the definition of RP to LMT (Layered Manufacturing Technology)
only ? This does surely result in a useable definition of a certain type of
activity as well. It does, however as said before in my view it is not good
to base this definition on a certain type of technology, as for the user the
technology actually used does not matter, and as it excludes other (not yet)
existing technologies to fulfill the same purpose.
The terms Automatic and 3D CAD data (or rather numerical data) are
process related, not technology related.

The abvove is of course an arguable position, the one limitation is OK
while the other is not. Still it is my position, and the result in my opinion
is a very useful definition.

Best Regards,

Lex Lennings.

Delft Spline Systems, The Netherlands.
We offer DeskProto: affordable Rapid Prototyping using CNC milling. --- website:

For more information about the rp-ml, see

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