CAD -> STL

From: André Dolenc (Helsinki University of Technology)
To: RP-ML
Date: Thursday, February 2, 1995
Subject: CAD -> STL
Terry Wohlers writes:
 > I don't doubt that you can produce a good STL file with a surface modeler
 > because many have.  But it can be tedius, and you are more likely to
 > accidentally produce a model that does not represent a closed volume.  I would
 > not want any rp-ml subscribers to conclude from your message that surface
 > modelers are as intuitive as solid modelers for prototyping.   Anyone agree or
 > disagree? :)

Difficult? I would say it is different. Many people use a particular
CAD system either due to historic reasons (decisions) or because it suits
better their particular needs or simply because of price.

If you are using a surface modeller that cannot tell you if your model is a
closed volume (give or take a tolerance) *and* you cannot check the resulting
STL file, then, I agree, you may have a problem.

However, technology exists that can verify an arbitrary surface model and tell if
it is or not a closed volume (again, give or take a tolerance) and *where*
the problems are located.

In fact, there are advantages in using a surface modeller because you don't
*need* to create a closed volume before using RP if you have a tool that can
do that for you.

Regards,
Andre'