HDTenEightyP/NetNews huggingface dataset:
From: katkere@krusty.eecs.umich.edu (Arun Katkere)
Subject: Shortest distance between two line _segments_
Followup-To: comp.graphics
Keywords: shortest distance, line segments, swept spheres
Reply-To: katkere@engin.umich.edu
Organization: University of Michigan EECS Dept., Ann Arbor, MI
Date: Sat, 21 Nov 1992 00:05:27 GMT

If I have two line segments ((x11, y11, z11), (x12, y12, z12)) and
((x21, y21, z21), (x22, y22, z22)), how can I find the shortest
distance between them? Finding Shortest line between two lines is
easy, but I couldn't think how I could do the same for segments.

The problem I am trying to solve is whether two swept spheres
intersect. It seems to be that if we find the shortest distance
between the line segments formed by the sweeping of the centers of
the two spheres and if this distance is less than the sum of the
radii of the two spheres, then they intersect, else they don't.
Hence, the query.

I didn't really explain that well, did I?
I'll try to draw that in 2D.
   ________________
  /|               \
 / |r1              \
| x|______________x |     Well, this is how the cross section
|                   |     of one of the swept spheres looks. 
 \                 /      If seg1 is the line segment between the
  \_______________/       two x's, and if radius and seg for
        sphere 2 is r2 and seg2, the two swept spheres intersect
	iff min_dist(seg1, seg2) < (r1+r2). I haven't really allocated
        much brain power to this, but the argument looks fine to me.
The question is how do I compute min_dist()?
Thanks,
-arun
-- 
+-----------------------------------------------------------------------------+
| Arun Katkere                      |   The University of Michigan AI Lab     |
| katkere@engin.umich.edu           |   147 ATL, 1101 Beal Avenue             |
| O:(313)763-1563 | R:(313)761-9462 |   Ann Arbor, MI 48109-2110              |
+-----------------------------------------------------------------------------+
Newsgroups: comp.graphics
From: ae007@yfn.ysu.edu (Daniel Newcombe)
Subject: Hitachi Data Tablet Digitizer ???
Organization: Youngstown State University/Youngstown Free-Net
Date: Fri, 20 Nov 1992 14:59:33 GMT


Hi all...   We have in our possesion one old Hitachi Data Tablet
Digitizer (That's what the label says) that we "inherited" from
RPI.  But as with most freebies, the manuals have gone the way
of the 8080 and are missing.  Does anyone else out there have
one of these, or know who I could contact about hopefully getting
a hold of them?   THANKS!!!
   -Dan
-- 
    -Dan Newcombe
Internet Address:  STDN@VM.MARIST.EDU
Youngstown Freenet: ae007@yfn.ysu.edu
GOAL: To put the world on 3.5" diskettes...  :)
From: ghuo@cs.ubc.ca (Gang Huo)
Newsgroups: comp.graphics
Subject: Reflection Data from Cloth Surface
Date: 22 Nov 1992 18:40:08 -0800
Organization: Computer Science, University of B.C., Vancouver, B.C., Canada
Distribution: na
NNTP-Posting-Host: duvel.cs.ubc.ca
Keywords: BRDF, Local Illumination, Anisotropy.


Is there anybody who has some real data about the reflectance from cloth
surface(s)? Or any source I can get them? Any information is highly 
appreciated. 

------------------------------------------------------------------------
Gang Huo
Dept. of Computer Science
Univ. of British Columbia
Vancouver, BC
Canada  V6T 1Z2
ghuo@cs.ubc.ca
(604)822-6994 (lab)
Newsgroups: comp.graphics
From: uwe@lilly.gris.informatik.uni-tuebingen.de (Uwe Kloos)
Subject: IGES Conversion
Summary: conversion to/from iges
Keywords: conversion to/from iges
Organization: Comp. Center (ZDV) U of Tuebingen, FRG
Date: Fri, 20 Nov 1992 13:15:14 GMT


Hello,
I,m looking for conversion software for IGES-files. Is there any public
domain software, espacially is there any possibility to convert a 
MOVIE.BYU file into an IGES file?
Thank you
Uwe Kloos
--
Uwe Kloos                [Internet] uwe@goya.gris.informatik.uni-tuebingen.de
Universitaet Tuebingen             Wilhelm Schickard Institut fuer Informatik
Auf der Morgenstelle 10, C-9                 7400 Tuebingen 1  -  DEUTSCHLAND
Phone: +49 (0) 7071 / 29-5464                     Fax: +49 (0) 7071 / 29-5466
From: watson@maths.uwa.oz.au (David Watson)
Newsgroups: comp.graphics
Subject: Re: Point inside a triangle
Date: 16 Nov 1992 23:50:04 GMT
Organization: The University of Western Australia
NNTP-Posting-Host: madvax.maths.uwa.oz.au

orourke@sophia.smith.edu (Joseph O'Rourke) writes:

>In article <BxsLL1.5H5@slipknot.rain.com> robert@slipknot.rain.com.UUCP (Robert Reed) writes:
>>The standard edge crossing test, which works for any other polygon, should work
>>fine here.  See page 34, Foley and van Dam Computer Graphics.  In brief you
>>count the number of polygon edges that cross a ray drawn from the point to
>>infinity.  An odd number of crossings means the point is interior.

>	Although this is a matter of taste, I find this inferior to
>the algorithm that I use, which tests if the point is left-of-or-on
>the three directed lines determined by pairs of vertices of the triangle.
>In the edge crossing code, one must deal with the ray crossing a
>vertex, being parallel to an edge, being collinear with an edge:

>			       /\
>			      /  \
>			     /    \
>			*---+------+------>

>oding these special cases requires care.  The other method has no
>no comparable special cases.  ut all methods, as someone else pointed
>out, are subject to tricky precision issues, because coordinates
>are multiplied.

A fail-proof method is to compute the barycentric coordinates.  For a
triangle {(x1,y1), (x2,y2), (x3,y3)} and some point (x0,y0), calculate

b0 = (x2 - x1) * (y3 - y1) - (x3 - x1) * (y2 - y1)
b1 = ((x2 - x0) * (y3 - y0) - (x3 - x0) * (y2 - y0)) / b0 
b2 = ((x3 - x0) * (y1 - y0) - (x1 - x0) * (y3 - y0)) / b0
b3 = ((x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0)) / b0 

Then if b1, b2, and b3 are all > 0, (x0,y0) is strictly inside the
triangle; if bi = 0 and the other two coordinates are positive, (x0,y0)
lies on the edge opposite (xi,yi); if bi and bj = 0, (x0,y0) lies on
(xk,yk); if bi < 0, (x0,y0) lies outside the edge opposite (xi,yi);
if all three coordinates are negative, something else is wrong.  This
method does not depend on the cyclic order of the vertices.

--
Dave Watson                          Internet: watson@maths.uwa.edu.au
Department of Mathematics            
The University of Western Australia               Tel: (61 9) 380 3359
Nedlands, WA 6009  Australia.                     FAX: (61 9) 380 1028
Newsgroups: comp.graphics,comp.sys.sgi,comp.unix.misc,comp.unix.questions
From: dhinds@leland.Stanford.EDU (David Hinds)
Subject: Re: Interactive vs Background users
Organization: DSG, Stanford University, CA 94305, USA
Date: Mon, 16 Nov 92 21:17:11 GMT

In article <1992Nov16.194645.24617@cc.ic.ac.uk> cmaae47@imperial.ac.uk writes:
>
>Unfortunately, this does not work for workstations. If the background 
>application is uses a large virtual memory space and pages regularly, 
>the memory space of "idle" programs gets paged out. Try a matrix inversion
>by Gaussian elimination where the augmented matrix is more than 4 times real
>memory.
>
>Whenever the user at the graphics console is in "think state", the processor
>will run the background job, even if its priority in the back-of-beyond.
>On Irix the kernel is locked into memory, you have a decent SCSI controller,
>(at least with the machines I know of, i.e. PI, 4D/3xx and Indigo) and a bit 
>of real memory is kept free for swapping, and the file system attempts to
>avoid fragmentation.

How's this:

      - Run big background jobs with npri +160 or something, so that they
        will never preempt anything with a better priority.

      - When you log in to the console, start a fast but small job, like
        an empty loop, at npri +128, that will just burn idle time and
        prevent the big job from ever getting paged in.  The big job will
        get zero CPU time while this job runs.

      - On logout, kill the CPU hog.  I don't know a clean way to do this
        automatically.  The big job will then start up again.

One way to enforce the priority scheme would be to set a system-wide CPU
and memory usage limits.  Then have a small program analogous to 'nice',
for starting big background jobs, that would be setuid root, and would
both increase the resource limits and start a job at the low priority.

        - David Hinds
          dhinds@allegro.stanford.edu
Newsgroups: comp.graphics
From: mcglough@rtsg.mot.com (Mark McGloughlin)
Subject: Color enhanced satellite images
Organization: Motorola Inc., Cellular Infrastructure Group
Date: Tue, 17 Nov 1992 13:42:46 GMT

Does anybody know of an ftp site where recent color enhanced satellite images
are stored. I am particularily interested in European images.

Thanks in advance.

PS: If this is a FAQ I am sorry. I do not normally read this group.

Mark McGloughlin...
-- 
---------------------------------------------------------------------
Mark McGloughlin       | UUCP:          ...uunet!motcid!glas!mcglough
Motorola Ireland Ltd.  | Internet:         mcglough@glas.rtsg.mot.com
Blackrock, Cork, Eire. | Ph: +353-21-357101.      Fax: +353-21-357635
From: kpm8447@tesla.njit.edu
Newsgroups: comp.graphics
Subject: Animation/Multimedia internships?
Date: 19 Nov 92 19:22:30 GMT
Organization: New Jersey Institute of Technology

I'm a soon to be graduate (BA in ART, concentration in Graphic Design
and Computer Animation - next May) and was trying to find information about
internships and/or jobs in the field of animation/multimedia design in New York
City or New Jersey.  Any info (or available internships) would be appreciated!
 - thanks

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Kirk Membry                              Marriage is for Life, Death is Forever
kpm8447@tesla.njit.edu                                    kpm8447@teak.njit.edu
kmembry@andromeda.rutgers.edu                            kpm8447@maple.njit.edu
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==
Newsgroups: comp.graphics
From: matrix@well.sf.ca.us (Frank Dunn)
Subject: NEW BOOK ON VIRTUAL REALITY, FOREWORD BY JARON LANIER
Organization: Matrix Information Services
Date: Tue, 24 Nov 1992 01:56:36 GMT



There is a new book available on the topic of VR.



       SILICON MIRAGE: THE ART AND SCIENCE OF VIRTUAL REALITY
            by Steven Aukstakalnis and David Blatner

   FOREWORD BY JARON LANIER, FOUNDER AND CHIEF SCIENTIST, VPL RESEARCH.




The first two paragraphs of the Foreword read as follows:


"Reading this book is a delight for me because it fills a suprisingly
long-standing gap in the literature of virtual reality. For the
enormous amount of interest and activity that virtual reality has 
inspired over the last few years, it is absolutely remarkable that I 
have had no book to recommend to people who come to me with the simple
question, 'What can I read to understand what this is all about?' I
feel that now there is such a book, and you are holding it in your hands.

Silicon Mirage is organized around the human sense organs, and this is
entirely appropriate. Virtual reality is distinct from other 
configurations of computer technology in that it places the human being
in the center. When we work with virtual reality systems, we begin with 
the question, "What, exactly, is a human body and how might we design
a machine that will most comfortably suit the natural modes of 
perception and action of a person?" So I am delighted to see an 
exposition that starts with the human body and nervous system and treats
the virtual reality equipment as transient attempts to mirror that
biological invarient."
----

In a clear, easy to understand style, Silicon Mirage covers everything
from the underlying mechanisms of sight, hearing and the sense of touch,
through the design of head-mounted displays, binaural 3-D sound, and
tactile/force feedback devices. There are also chapters on the human 
factors considerations of immersive VR systems, applications from a 
broad cross-section of industries and more.


SILICON MIRAGE: THE ART AND SCIENCE OF VIRTUAL REALITY
by Aukstakalnis and Blatner

328 pgs, 120+ photos and illus, 4 pgs. color plates, pub Nov. 1992
by Peachpit Press (ISBN 0-938151-82-7).

PRICE: $15.00

Available at bookstores across N. America the day after Thanksgiving
or immed. by sending a check or money order for $15.00 + $5 for 
P/H to:


Matrix Information Services
Book Dept. 
18560 Bungalow Drive
Lathrup Village, MI 48076
(313) 559-1526
(313) 559-1436 (Fax)
matrix@well.sf.ca.us


Newsgroups: comp.graphics
From: orourke@sophia.smith.edu (Joseph O'Rourke)
Subject: Re: Point inside a triangle
Organization: Smith College, Northampton, MA, US
Date: Tue, 17 Nov 1992 11:59:26 GMT

In article <Bxtz3s.6xA@slipknot.rain.com> robert@slipknot.rain.com.UUCP (Robert Reed) writes:
>In article <1992Nov16.115211.23169@sophia.smith.edu> orourke@sophia.smith.edu (Joseph O'Rourke) writes:

>|	Although this is a matter of taste, I find this inferior to
>|the algorithm that I use, which tests if the point is left-of-or-on
>|the three directed lines determined by pairs of vertices of the triangle.
>|In the edge crossing code, one must deal with the ray crossing a
>|vertex, being parallel to an edge, being collinear with an edge:
>
>The special cases are trivial to discard, [...]

Yes, I see it is more straightforward than I thought.  Thanks for the
explanation.

>Now, it's not clear from your description how your left-of-or-on algorithm
>works, [...]

If the triangle is T=(a,b,c) in ccw order, and the test point is p, then
p is in T iff

	LeftorOn(a,b,p) && LeftorOn(b,c,p) && LeftorOn(c,a,p)

LeftorOn(x,y,z) computes the signed area of that triangle, and tests
for >= 0 (the ==0 case is "On").
Newsgroups: comp.graphics
From: ph+@cs.cmu.edu (Paul Heckbert)
Subject: Re: Editing postscript
Organization: School of Computer Science, Carnegie Mellon
Date: Fri, 20 Nov 1992 18:58:29 GMT

In article <BxGLrE.85A@ens-lyon.fr> ameroni@archeboc.ens-lyon.fr (Alberto Meroni) writes:
>What I would really like to do is adding in some way 
>some drawing to an existing postscript file 

A cute trick I learned from Petr van Blokland, a typographer
and mac programmer in the Netherlands:

If you're generating the postscript files yourself, then don't use
standard postscript, use the dialect of postscript used by Adobe Illustrator.
When you Save a file in Illustrator, the file format it uses is valid
postscript with extra information contained in comments, that allows
it to construct structural info, handles, and other interactive tools.
If your programs generate postscript files of this type, then you'll be
able to edit them interactively using Illustrator!

The Illustrator file format is described in some documentation that's
available from Adobe (anyone know how to order it?), or you can just
look at a sample Illustrator file and figure it out, I suppose.

-Paul

Paul Heckbert						    ph@cs.cmu.edu
Computer Science Dept., Carnegie Mellon University
5000 Forbes Ave, Pittsburgh PA 15213-3891, USA
Newsgroups: comp.graphics
From: joanne@probitas.cs.utas. (Joanne Sun)
Subject: Convert X-window screen dump to Mac format
Organization: Dept. of Comp. Sci., Uni of Tas
Date: Tue, 17 Nov 1992 23:36:12 GMT

I am trying to display an X-window screen dump on a color Mac.
I had gone through the following steps:

- xwd								/* grab an X-window image */

- xwdtopnm			/* convert xwd format to ppm format */

- ppmtopict  /* convert ppm format to Mac PICT format */

- mcvert -dDqv filename  /* translate the file to MacBinary format.  
 								                    MAC_DTYPE is set to PICT */

- transfer the file to Mac using ftp command (binary mode)

- using ResEdit change the file format to PICT 

However, the file is opened as a blank picture by MacdrawII or
 Canvas3.04.

Can anyone tell me what I did wrong or How I can display a
X-window screen dump on a color Mac?

Any help will be greatly appreciated.

Joanne Sun  


Newsgroups: comp.graphics
From: dhaliwa@ecf.toronto.edu (DHALIWAL BIKRAM SINGH)
Subject: mouse screwing up screen
Organization: University of Toronto, Engineering Computing Facility
Distribution: na
Date: Mon, 23 Nov 1992 23:23:58 GMT

I use hidemouse() to hide the mouse and then draw my text to 
the screen, and then use showmouse() to bring the mouse cursor
back.  OK, this works O.K., however if I attempt to do it again
after I have actually drawn anything my text looks like crap.  

What am I doing wrong??  I am hiding and showing the mouse
cursor at all instances of writing to the screen.


-- 
 
.............................................
 Bikram Dhaliwal (dhaliwa@civ.toronto.edu) 
 Toronto        (dhaliwa@ecf.toronto.edu)
From: petterr@stud.cs.uit.no (Petter Reinholdtsen)
Newsgroups: comp.graphics
Subject: Finding duplicating pictures.
Keywords: duplicat, pictures.
Date: 22 Nov 92 21:08:25 GMT
Organization: University of Tromsoe, Norway

Are there some program to find duplicating pictures (gif, jpg, etc..), by
looking
at the palette, size of picture, and the CRC? The filename changes, but these
should stay put.

-- 
##>  Petter Reinholdtsen <##	| petterr@stud.cs.uit.no
Tlf: +47 83 80 818		| Petter Reinholdtsen at 2:502/802.153
co/Lockert, Oestavinden 8	| University of Tromsoe
9015 Tromsoe			| Norway
Newsgroups: comp.graphics
From: brownea@cc.uvcc.edu
Subject: GIF, TIFF, and PCX formats requested
Organization: Utah Valley Community College
Date: Tue, 24 Nov 1992 03:25:40 GMT

Hi, I'm looking for information on the different file formats. Specifically
GIF, TIFF, and PCX.  Any help would be great.
Newsgroups: comp.graphics
From: steve@fulcrum.oz.au (Steve Taylor)
Subject: Re: SVGA animation maker?
Keywords: animation FLI animation
Organization: The Fulcrum Consulting Group
Date: Mon, 23 Nov 1992 03:21:15 GMT

jonathan@rahul.net (Jonathan Heiliger) writes:

>In article <banister.721874213@rintintin.Colorado.EDU> 
>banister@rintintin.Colorado.EDU (Trevor Banister) writes:

>>Does anyone know of an SVGA animation maker?
>>Any format is allright. FLI, GL, DL, etc.
>>I'm interested in 640x480x256 or greater.

>   What do you mean by 'SVGA'?  The specs that you list above are not S-VGA.  
As far as I know, VGA = 320*200*256, SVGA = 640*400*256 and better. SVGA is
not a well defined spec in the sense that VGA is, but just a blanket term for
all the higher mode that most card manufacturers support. The specs listed
above are SVGA.

>Just for reference Autodesk Animator/PRO should do what your looking for.
Provided you're looking for a full blown 2d animation program - it's quite
expensive. For just turning a bunch a files into a playable animation, there
are certainly quite a few FLI makers. The only names I can think of at the
moment are DTGA (Daves Targa Animation Program - Targa files -> FLI) and
hcfli05.zip (+ its player, hcplay07.zip) which produce 32000 FLIs, for use
with card fitted with the Sierra Hicolor dac. There are also some FLI makers
which will produce normal 256 colour FLIs, but I'm afraid I can't think of
names right now.


							Steve
From: upbikkas@uncc.edu (Udayabhanu P Bikkasani)
Newsgroups: comp.graphics
Subject: help needed ..compiling sphigs source code
Date: 23 Nov 92 01:36:49 GMT
Reply-To: upbikkas@uncc.edu
Organization: University of NC at Charlotte

can some one tell mehow to make the bin file out of the sphigs source code

i am using sun/sparc
sun os 4.1

Keywords: 


---
       ----------------------------------------------------------------------
            UdayaBhanu Bikkasani               upbikkas@unccsun.uncc.edu
            9520, #f, shannon green            
            charlotte  NC-28213                ck128@freenet.cwru.edu 
                              
                            phone: 704-549-4260
       ----------------------------------------------------------------------
Newsgroups: comp.graphics
From: icarus@malloco.Ing.puc.cl (Eduardo Jimenez)
Subject: MPEGXING QUESTION..HELP!
Organization: Pontificia Universidad Catolica de Chile
X-Newsreader: Tin 1.1 PL5
Date: Wed, 18 Nov 1992 15:58:55 GMT

 Hello, well I just used the mpexing player for windows, the animations are
really cool, but the animation runs on my computer only in grays, (like a VGA MONO).In others computer that I saw the animations runs in color...
 Somebody Knows Why?...


  My graphic Card is a TRIDENT 1024 Bios C3.0,

 BTW, The Mpegxing, modify my pallete to grays too....why!



 If somebody can Help me I'll be gratefull....

ICARUS@MALLOCO.ING.PUC.CL

Newsgroups: comp.graphics
From: stanb@benchsco.sco.COM (Stan Banasky)
Subject: Re: CORAL (Corral?  Chorale?) -- Anyone heard of it?
Organization: The Santa Cruz Operation, Inc.
Date: Wed, 18 Nov 1992 19:01:04 GMT

In article <27626@oasys.dt.navy.mil>, poy@oasys.dt.navy.mil (Stephen Poy) writes:
|> hello,
|> 
|> what i think youre talking about is coreldraw.  it is a design/graphics
|> package that is debatably [sp] the best of its kind on the market.
|> it only (to my knowledge) runs on pc's.  i believe it goes for about
|> $400.00 on the market, however if youre patient you may find a used
|> copy for as low as $200.00 (like me). it is used for all kinds of drawing
|> applications.
|> 
|> -
|> good luck,
|> stephen

Actually, Prior Data Sciences has ported CorelDraw to the following 
platforms:

	SCO ODT
	DECstation 3100 and 5000
	DG AViiON
	HP Apollo Series 400 and 700
	IBM RS/6000
	Intergraph
	Silicon Graphics
	Sun SPARCstation (Motif and Open Look)
	(possibly more)

For the most part it is keystroke compatible with the Windows version. They
are currenlty shipping version 2.01.1 which includes floating license
technology (earlier versions may have as well).

I'm not sure on the pricing.

You can reach them at:

	Prior Data Sciences
	Product Sales Inc.
	240 Michael Cowpland Drive
	Kanata, Ontario, Canada K2M 1P6
	Phone:	(613) 591-7235
	Fax:	(613) 592-1278

NOTE: I have no connection to nor any relationship with Prior or Corel 
other than having looked at their products for evaluation.

--------------------------------------------
Stan Banasky
Information Services
The Santa Cruz Operation
VOICE:	(408) 425-7222
E-MAIL:	stanb@sco.COM   [or]   ...!sco!stanb
Newsgroups: comp.graphics
From: robert@slipknot.rain.com (Robert Reed)
Subject: Re: Point inside a triangle
Reply-To: robert@slipknot.rain.com.UUCP (Robert Reed)
Organization: Home Animation Ltd.
Date: Tue, 17 Nov 1992 20:30:53 GMT

In article <1992Nov17.132302.6345@sophia.smith.edu> orourke@sophia.smith.edu (Joseph O'Rourke) writes:
|
|It seems from your description that points on the boundary of the triangle
|T are not handled consistently by the ray algorithm.  Below, a is not in T
|but b is in T.
|
|			       /\
|			      b  \
|			     /    \
|			    +--a---+       
|
|At least this seems to be what the code that Michael Goza posted does.
|Am I right?

A trivial modification to the algorithm as I suggested it would correct for
this.  If the boundaries of any polygon are to be considered interior, then if
a bounding edge is collinear with the test point, it is sufficient to test
whether the point is within the interval of the edge.  If it is not, the edge
is trivially rejected as before.  If it is, the algorithm can be prematurely
terminated with a TRUE result.
________________________________________________________________________________
Robert Reed			Home Animation Ltd.		503-656-8414
robert@slipknot.rain.com	5686 First Court, West Linn, OR 97068

My friend George is a radio announcer.
When he walks under a bridge, you can't hear him talk.
--Steve Wright
________________________________________________________________________________
Newsgroups: comp.graphics