Re: Attn. Pro/Engineer users!! Attn. Pro/Engineer users!!

From: Peter H. Gien (
Date: Fri Dec 01 1995 - 18:20:02 EET

Tony wrote:

>>The only disadvantage of the STL file that I see is the inability to
exactly represent curved surfaces. However, well-written software can
easily process files with >200,000 facets in a reasonable amount of time,

While I agree in general that the simplicity of STL files is what makes them
popular, I would like to add that modifying the files has proven to be a
stumbling block. For example, reading 200,000 triangles into Pro/E will bring it
to it's knees. Same is true with most other CAD systems. I have found, however,
that there are several CAD systems that support Polyhedral models, since that is
what an STL file is.

For example, 3D/EYE can read a large STL file without any problem. It also
repairs normals correctly. Having read the file into 3D/EYE, one can convert it
to say an OBJ or DXF file. Both of these formats will produce an exact one to
one match of the triangles. Then read the file into Caligari TrueSpace2 and you
will be able to refine the mesh, push and pull surfaces and perform many other
manipulations. Another wonderful program for manipulating mesh files is 3DStudio
from AutoDesk although it is a little pricey.

If you confine your CAD outlook to traditional mechanical design software, then
you will find a dearth of tools for manipulating meshes. But if you look beyond
CAD, and start digging into the rendering and animation tools you will be
pleasantly surprised. A good source for this 3DDesign magazine, published by

Peter Gien
POGO International, Inc.

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