To LUGNET HomepageTo LUGNET News HomepageTo LUGNET Guide Homepage
 Help on Searching
 
Post new message to lugnet.cadOpen lugnet.cad in your NNTP NewsreaderTo LUGNET News Traffic PageSign In (Members)
 CAD / 4743
4742  |  4744
Subject: 
Re: 1-8sphe.dat tesselations compaire image
Newsgroups: 
lugnet.cad
Date: 
Wed, 4 Oct 2000 03:56:53 GMT
Viewed: 
801 times
  
"Manfred Moolhuysen" <moom@nospamchello.nl> wrote in message
news:G1uxnB.I8H@lugnet.com...
4 days ago I've posted that I've made a compaire image showing the two
possible alternatives for surface tesselations for the 1-8sphe.dat • primitive.
I've waited a while before giving my own opinion, but here it is:

For me, the proposed alternative for the tesselation, using 16 triangles • per
sector, has no substantial benifit over the tesselation as used in the
existing official primitive, using 9 quads and 4 triangles per sector.
My arguments:

The inaccurate coordinate values that the old 1-8sphe.dat primitive still • had,
have been resolved with a fix submitted by Axel Poqué and I in August this
year. (This fix is part of the recent 2000-02 update)

I think that face distribution with 9 quads and 4 triangles isn't a
disadvantage compaired with Travis Cobbs his distribution with 16 • triangles.
In the compaire image http://members.ams.chello.nl/mmoolhuy/compaire.jpg
it seems to me that the existing 9 quads and 4 triangles tesselation is • even
better looking that the proposed 16 triangle alternative. In my opinion, • the
dome on the right looks a little smoother than the dome on the left.

Calculation of intersection points with other faces is easyer for the • existing
primitive than for the proposed alternartive.


However, I appreciate that Travis did made an effort, and hope I haven't
discouraged him to make other contributions in the future. After all, he • was
right in saying that (at least) the accuracy of the old primitive had to • be
improved.

Works for me.  Don't worry about the discouragement part.  In all fairness,
I hadn't yet spent much time on generating the file I produced, due to the
fact that I had already gone to the large amount of effort to get the
algorithm working for my LDView program.  That meant that all I had to do
was get the triangles written to a file, which was pretty straightforward.

Also, the lack of response seems indicative of either complete lack of
preference by the community, or an unwillingness to take sides.  Either way,
you're right about your new sphere primitive being fine, and it does have
the advantage of precedence (both by being generated first, and closely
resembling the original primitive).

--Travis Cobbs (tcobbs@san.REMOVE.rr.com)



Message is in Reply To:
  Re: 1-8sphe.dat tesselations compaire image
 
4 days ago I've posted that I've made a compaire image showing the two possible alternatives for surface tesselations for the 1-8sphe.dat primitive. I've waited a while before giving my own opinion, but here it is: For me, the proposed alternative (...) (24 years ago, 3-Oct-00, to lugnet.cad)

19 Messages in This Thread:









Entire Thread on One Page:
Nested:  All | Brief | Compact | Dots
Linear:  All | Brief | Compact
    

Custom Search

©2005 LUGNET. All rights reserved. - hosted by steinbruch.info GbR