RE: Revit

From: Charles Overy (cwho@lgmmodel.com)
Date: Tue Apr 22 2003 - 04:11:49 EEST


Bob,

In a word NO.

More Detail:
Revit, only has three "built in" export formats
DWG - AutoCad
DXF - generic CAD export
DGN - Bently Systems

As of last fall it was not exporting ACIS or other solids data to Autocad,
only a tessellated mesh.
Great you might say, a tessellated mesh, I can go to STL from a tessellated
mesh via 3ds or the like.

However, meshes that I exported from Revit were HIGHLY degenerate. They
had holes, flipped faces, etc.
I would be happy to send you some if you want to have a look. I have not
worked with the DGN as I do not have Bentley. The DXF closely mirrors the
DWG. They could be used as a snap grid to redraw the geometry but were not
useful in anything more that very basic cases as a starting point for mesh
repair.

In addition, if you are considering building Architectural models from Revit
files you will face the problem that I call radical scale down. Basically,
even if you own a 810, Titan or the like you are going to be running an arch
model at say 1" = 8' or smaller. 1/96th the original size to maybe 1/400
the real world size. Now Revit is great program because it is truly
parametric. You can call up a window and place it into a wall. Revit also
knows the thickness of the glass in the window. Even expensive .25" glass at
1/96 then is .0026" thick when you make the prototype. Now imagine a small
office building with a "curtain wall" of glass representing 60 percent of
the model and the model at 1" = 20' . You just built a Vat O' Dust.
Because it is a parametric modeler, you could create window substitutions,
but depending on the window library you cannot always just say you want 1'
thick glass. Sometimes you have to modify each window.... Now what about a
steel I beam with a .25" section... or a cable holding up a fabric canopy...

Have I been there... yes.
I have had meetings with Revit's old director of sales and their current
CEO. At one point they were going to write STL export into the code for us
(we were going to guarantee sales or pay) but that was before they got
purchased by Autodesk. We ran several sample models for them which they
liked. As of last fall there was no movement that I could ascertain to
embrace RP.

In the end we resorted to development of a more general solution to at
least some of the problems that I describe above. The software solution
solves some of the radical scale down issues and can work with existing RP
mesh preprocessing software like Magics, Marcam, Stl Editor, to create a
buildable mesh. The plan is to have operational stl file resurfacing
available late next week.

Please let me know if you would like further information on Revit, RP in
architecture, or our solutions.

Best wishes

Charles Overy
Director of Engineering, LGM

-----Original Message-----
From: owner-rp-ml@rapid.lpt.fi [mailto:owner-rp-ml@rapid.lpt.fi]On Behalf Of
Bob Olsen
Sent: Monday, April 21, 2003 4:32 PM
To: 'rp-ml@rapid.lpt.fi'
Subject: Revit

Anyone know if AutoDesk's Revit software (an architectural package) can
create an STL file, or how that is done? Thanks in advance!
Regards, Bob http://www.protogenic.com
Protogenic - Always on time,
                          Always great Customer service,
                              Always top quality.

=======================================
Bob Olsen sales manager
1490 West 121st Avenue, Suite 101
Westminster, CO 80234-3497

* Direct: 303-453-3990
* Main: 303-252-0212
* Fax: 303-252-0223
* bob@protogenic.com
* web: http://www.protogenic.com
=======================================



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