Re: Slice Formats....

From: Anthony Martin (
Date: Sun Mar 03 1996 - 10:10:53 EET

On 3 Mar 1996, Peter H. Gien wrote:
> Computational burden of computing normal vectors from the right hand rule is
> minimal.
> 50,000 facets would involve 50,000 * 6 multiplies and 50,000 * 3 additions.
> Doing this on a 60MHz Pentium would take around 1/2 of a second. On my old
> intel 80286/287 it would have taken around 2 seconds.

And how long would it take these machines to read the normal data from a
file? I suspect quite a bit longer. Especially if it is an ASCII file.
I agree that it is foolish to include normal data in a mesh file. (The
above estimate seems a bit too fast, especially if you consider
normalizing the vector which includes a square root operation, but still,
the time required on a modern computer is insignificant.)

> OK, would the original perpertrator of the STL format please identify
> yourself!

I doubt anyone would admit to doing it.


This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:37:14 EEST