RE: rp definition

From: Jeff Katz (
Date: Sat Feb 03 2001 - 20:02:02 EET

I'd like to point out that the definition that Elaine posted at the top of
the thread was taken from the 1992 Rapid Prototyping Report, which if I'm
not mistaken, was published by non other than Terry Wohlers. Terry, I have
to agree with Lex, the original definition is much appropriate. What was
the process of its evolution into the more recent, more convoluted one?

Jeff Katz
773.477.7374 x203
Fast, Free, Secure

-----Original Message-----
From: []On Behalf
Of Delft Spline Systems
Sent: Saturday, February 03, 2001 3:43 AM
To: Terry T. Wohlers
Subject: Re: rp definition

At Friday 02/02/2001 , Terry Wohlers wrote:
>I've been using the following to briefly define/describe RP:
>Rapid prototyping (RP) is a relatively new class of technology used for
>building physical models and prototype parts from 3D computer-aided design
>(CAD) data. Unlike CNC machines tools, which are subtractive in nature, RP
>systems join together liquid, powder and sheet materials to form complex
>parts. Layer by layer, RP machines fabricate plastic, wood, ceramic, and
>metal objects based on thin horizontal cross sections taken from a computer

Hi Terry,

When posting this message you must have realized that your statement
is in fact screaming for comments. A few comments on your exclusion
of CNC have already been sent, and I do want to add mine.

In my opinion the definition of RP should be based on the users point of
view, on the applications served, on the end-result. It should not be based
on the technology used, as from a user point of view is it absolutely
uninteresting which technology is applied inside the black box called RP
Your definition is RP is even more restricted as it also excludes full 3D
additive technologies like the one BPM has been working on in the past.
It is (do forgive my example) like defining a locomotive (train) as a
that pulls a train by boiling water with coal and using the steam for

For a definition I do fully agree with the one that was posted by Elaine
at the start of this thread.

Of course I do understand the resulting problem that in that case RP is
no longer a small and clear research area, with only a limited number
of players in the field. (in contrast to the thousands of CNC-related
suppliers worldwide. Limitation might indeed be needed here, however
then a definition including the word 'additive' is more appropriate.

Sorry for the strong wording, however as our prime activity is
"RP using CNC" I just had to respond.

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

For more information about the rp-ml, see

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