RE: [rp-ml] The OpenRP Initiative

From: Deelip Menezes <>
Date: Wed Jun 02 2004 - 15:49:25 EEST


When we were drawing up the specifications of the RP file format we did
add "model properties", including unit, color, etc. When converting back
to STL we tried to have a system whereby these properties were written
to the STL header and similar available spaces. As we added more
properties, the whole thing became more and more messy to a point that
we faced the risk of conventional STL translators finding our STL files
illegal. So we scrapped the whole idea and decided that as a first step
we would store only the data that is stored in a STL file.

We know that people would want the RP file format to contain more
information than whats present in the STL file format. Currently the
best solution on the cards is the following:

We create a superset of the RP file format (say, RPX, X stands for
Extended) and let this file contain the RP file data. We could then
store any other information that we need to (unit, color, bounding box,
material, etc.) in the RPX part of the file. Besides standard properties
we could even leave space for custom properties, similar to MS Word
custom properties.

We decided that before jumping into doing this, it would be best to take
suggestions from people in the industry like yourself. We hope to put
together a list of such "properties" and other data that you and other
people would like to see in the file format.


-----Original Message-----
From: Charles Overy []
Sent: Wednesday, June 02, 2004 5:35 PM
To: Deelip Menezes;
Subject: Re: [rp-ml] The OpenRP Initiative


I think this is as good a place as any to start. Thank you for your

I think though, that when you identify two main problems, large file
size and security, you leave a great deal unsaid. If I had a " top 10
problems with stl"" list, security would not make it.

With your robust tool set would it not be possible to introduce a file
header that would include basic file information like..... what unit of
measure the program was drawn in? I have to stand up for my old
engineering professor who used to yell, "the answer is wrong without the
UNITS". If on translation back to stl, the OPEN RP toolset put the
unit of
measure in a comment line, that would be really great.

Here is my list of things that might be included in an OPEN RP header.
Units Part bounding box (so a program can read it before it reads the
entire mesh) Date Program that created the mesh UV coordinates (little
out of my league here , but some method of defining surface color or
texture) User notes pointer to texture or color files Standard format
for nesting of multiple discrete shells or meshes within one file.

Your work is a good start.


----- Original Message -----
From: "Deelip Menezes" <>
To: <>
Sent: Tuesday, June 01, 2004 11:55 PM
Subject: [rp-ml] The OpenRP Initiative

> Dear List,
> There have been many discussions on this list about the STL file
> format. Those who took part in those discussions will find the
> following interesting.
> Today Floating Point Solutions launched OpenRP, a non-profit
> initiative which aims at offering the RP industry an alternative mode
> of data exchange while maintaining perfect compatibility with the
> industry standard STL file format. OpenRP offers the RP industry a new

> RP file format and free software to read and write RP files.
> OpenRP is not another monopolistic attempt to replace the STL file
> format. The industry standard file format is, and for the foreseeable
> future, will be the STL file format. OpenRP simply offers an
> alternative means of efficient and secure data exchange from one party

> to another. All this completely free of cost.
> Please visit to learn more about the initiative
> and download the free software. To get an overview of OpenRP you can
> read our press release at
> Yes, I know it is a sin to blow your trumpet on this list and I wont
> be surprised if I am crucified for that. But I couldn't think of a
> better place to post this information.
> I request you to take time and leave some feedback while you are at
> the OpenRP web site. Your suggestions/criticizm are most welcome and
> will go a long way in making OpenRP useful to the RP industry.
> Regards,
> Deelip Menezes
> Director
> Floating Point Solutions Private Limited
Received on Wed Jun 02 15:14:17 2004

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