apr comp graphics frequently asked questions faq archive name graphics faq this message is automatically posted once a week or so in an effort to cut down on the repetitive junk in comp graphics it was last changed on apr if you have answers to other frequently asked questions that you would like included in this posting please send me mail if you don t want to see this posting every week please add the subject line to your kill file thank you if your copy of the faq is more than a couple of weeks old you may want to seek out the most recent version the latest version of this faq is always available on the archive site pit manager mit edu alias rtfm mit edu as pub usenet news answers graphics faq john john grieggs grieggs jpl devvax jpl nasa gov johng portal com last update apr sorry i haven t posted this for a couple of weeks but i was called out of town due to a death in the family this is reality folks what s new siggraph online bibliography project spencer cgrg ohio state edu grieggs jpl devvax jpl nasa gov contents general references for graphics questions drawing three dimensional objects on a two dimensional screen quantizing bit images down to bits converting color into grayscale quantizing grayscale to black white rotating a raster image by an arbitrary angle free image manipulation software format documents for tiff iff biff nff off fits etc converting between vector formats how to get pixar films how do i draw a circle as a bezier or b spline curve how to order standards documents how to ftp by email how to tell whether a point is within a planar polygon how to tessellate a sphere specific references on ray tracing and global illumination siggraph information online siggraph panels proceedings available graphics mailing lists specific references on file formats what about gif what is morphing how to ray trace height fields how to find the area of a d polygon how to join acm siggraph where can i find mri and ct scan volume data specific references on spatial data structures including quadtrees and octrees where can i get a program to plot xy z data or f x data specific references on pex and phigs siggraph online bibliography project general references for graphics questions computer graphics principles and practice nd ed j d foley a van dam s k feiner j f hughes addison wesley isbn procedural elements for computer graphics david f rogers mcgraw hill isbn mathematical elements for computer graphics nd ed david f rogers and j alan adams mcgraw hill isbn three dimensional computer graphics alan watt addison wesley isbn an introduction to ray tracing andrew glassner ed academic press isbn graphics gems andrew glassner ed academic press isbn graphics gems ii james arvo ed academic press isbn graphics gems iii david kirk ed academic press isbn with ibm disk or with mac disk digital image warping george wolberg ieee computer society press monograph isbn digital image processing nd ed rafael c gonzalez paul wintz addison wesley isbn a programmer s geometry adrian bowyer john woodwark butterworths isbn pbk an automatic mail handler at brown university allows users of computer graphics principles and practice by foley van dam feiner and hughes to obtain text errata and information on distribution of the software packages described in the book also users can send the authors feedback to report text errors and software bugs make suggestions and submit exercises to receive information describing how you can use the mail handler simply mail graphtext cs brown edu and put the word help in the subject line use the subject line software distribution to receive information specifically concerning the software packages srgp and sphigs errata for an introduction to ray tracing is available on wuarchive wustl edu in graphics graphics books introtort errata errata for digital image warping is in the same directory as digital image warping errata all c code from the graphics gems series is available via anonymous ftp from princeton edu look in the directory pub graphics graphicsgems for the various volumes gems gemsii gemsiii and get the readme file first errata to graphics gems and graphics gems ii is available on wuarchive wustl edu in graphics graphics books a list of computer graphics computational geometry and image processing journals is available from juhana kouhia jk cs tut fi drawing three dimensional objects on a two dimensional screen the simple answer is you divide by the depth for a more verbose explanation see any of the above references starting with the foley van dam feiner hughes computer graphics book is certainly a good start chapter is viewing in d then read chapter visible surface determination for more information go to chapter for shading chapter for clipping and branch out from there quantizing bit images down to bits find a copy of color image quantization for frame buffer display by paul heckbert siggraph proceedings page there are other algorithms but this one works well and is fairly simple implementations are included in most raster toolkits see item below a variant method is described in graphics gems p note that the code from the graphics gems series is all available from an ftp site as described above check out john bradley s diversity algorithm which is incorporated into the xv package and described in the back of the manual the imagemagick package see section for where it is contains another quantizing algorithm which is presented as doing a better job than the other algorithms but slower there s also an implementation of wan wong and prusinkiewicz an algorithm for multidimensional data clustering transactions on mathematical software vol june pp avialable as princeton edu pub graphics colorquant shar this code in modified form appears in the utah raster toolkit as well converting color into grayscale the ntsc formula is luminosity red green blue quantizing grayscale to black white the only reference you need for this stuff is digital halftoning robert ulichney mit press isbn but before you go off and start coding check out the image manipulation software mentioned in item below all of the packages mentioned can do some form of gray to b w conversion rotating a raster image by an arbitrary angle the obvious but wrong method is to loop over the pixels in the source image transform each coordinate and copy the pixel to the destination this is wrong because it leaves holes in the destination instead loop over the pixels in the destination image apply the reverse transformation to the coordinates and copy that pixel from the source this method is quite general and can be used for any one to one d mapping not just rotation you can add anti aliasing by doing sub pixel sampling however there is a much faster method with antialising included which involves doing three shear operations the method was originally created for the im raster toolkit see below an implementation is also present in pbmplus reference a fast algorithm for raster rotation by alan paeth awpaeth watcgl waterloo edu graphics interface vancouver an article on the im toolkit appears in the same journal an updated version of the rotation paper appears in graphics gems see section under the original title free image manipulation software there are a number of toolkits for converting from one image format to another doing simple image manipulations such as size scaling plus the above mentioned color gray gray b w conversions here are pointers to some of them xv by john bradley x based image display manipulation and format conversion package xv displays many image formats and permits editing of gif files among others the program was updated see the file contrib xv tar z on export lcs mit edu pbmplus by jef poskanzer comprehensive format conversion and image manipulation package the latest version is always available via anonymous ftp as ftp ee lbl gov pbmplus tar z wuarchive wustl edu graphics graphics packages pbmplus pbmplus tar z and export lcs mit edu contrib pbmplus tar z im raster toolkit by alan paeth awpaeth watcgl uwaterloo ca provides a portable and efficient format and related toolkit the format is versatile in supporting pixels of arbitrary channels components and bit precisions while allowing compression and machine byte order independence the kit contains more than tools with extensive support of image manipulation digital halftoning and format conversion previously distributed on tape c o the university of waterloo an ftp version will appear someday utah rle toolkit conversion and manipulation package similar to pbmplus available via ftp as cs utah edu pub urt princeton edu pub graphics urt and freebie engin umich edu pub urt fuzzy pixmap manipulation by michael mauldin mlm nl cs cmu edu conversion and manipulation package similar to pbmplus version available via ftp as nl cs cmu edu usr mlm ftp fbm tar z ftp uu net pub fbm tar z and ucsd edu graphics fbm tar z img software set by paul raveling raveling venera isi edu reads and writes its own image format displays on an x screen and does some image manipulations version is available via ftp as export lcs mit edu contrib img tar z and venera isi edu pub img tar z along with a large collection of color images xim x image manipulator by philip r thompson it does essential interactive image manipulations and uses x r and the osf motif toolkit for the interface it supports images in and bit formats reads writes and converts to from gif xwd xbm tiff rle xim and other formats writes level postscript other utilities and image application library are included not a paint package available via ftp from gis mit edu xloadimage by jim frost madd std com reads in images in various formats and displays them on an x screen available via ftp as export lcs mit edu contrib xloadimage and in your nearest comp sources x archive xli by grame gill is an updated xloadimage with numerous improvements in both speed and in the number of formats supported available in the same places as xloadimage contrib tape comp sources x archives tiff software by sam leffler sam okeeffe berkeley edu nice portable library for reading and writing tiff files plus a few tools for manipulating them and reading other formats available via ftp as ucbvax berkeley edu pub tiff tar z or ftp uu net graphics tiff tar z xtiff an x tool for viewing a tiff file it was written to handle as many different kinds of tiff files as possible while remaining simple portable and efficient xtiff illustrates some common problems with building pixmaps and using different visual classes it is distributed as part of sam leffler s libtiff package and it is also available on export lcs mit edu ftp uu net and comp sources x xtiff was announced in it includes xlib and xt versions alv a sun specific image toolkit version posted to comp sources sun on dec also available via email to alv users request cs bris ac uk popi an image manipulation language version posted to comp sources misc on dec imagemagick an x package for display and interactive manipulation of images includes tools for image conversion annotation compositing animation and creating montages imagemagick can read and write many of the more popular image formats available via ftp as export lcs mit edu contrib imagemagick tar z khoros a huge meg graphical development environment based on x r khoros components include a visual programming language code generators for extending the visual language and adding new application packages to the system an interactive user interface editor an interactive image display package an extensive library of image and signal processing routines and d d plotting packages available via ftp as pprg eece unm edu pub khoros laboimage a sunview based image processing and analysis package it includes more than image manipulation processing and measurement routines on line help plus tools such as an image editor a color table editor and several biomedical utilities available via anonymous ftp as ads com pub vision list archive shareware laboimage tar z the san diego supercomputer center image tools software tools for reading writing and manipulating raster images binaries for some machines available via anonymous ftp in sdsc edu sdscpub the independent jpeg group has written a package for reading and writing jpeg files ftp to ftp uu net graphics jpeg jpegsrc v tar z don t forget to set binary mode when you ftp tar files for you milnet folks who still don t have name servers the ip addresses are ads com cs utah edu coral cs jcu edu au export lcs mit edu freebie engin umich edu ftp ee lbl gov ftp uu net or gis mit edu gondwana ecr mu oz au karazm math uh edu marsh cs curtin edu au nic funet fir ftp ncsa uiuc edu nl cs cmu edu pit manager mit edu pprg eece unm edu princeton edu sdsc edu ucbvax berkeley edu venera isi edu weedeater math yale edu wuarchive wustl edu zamenhof cs rice edu please do not post or mail messages saying i can t ftp could someone mail this to me there are a number of automated mail servers that will send you things like this in response to a message see item below for details on some also the newsgroup alt graphics pixutils is specifically for discussion of software like this you may find useful information there format documents for tiff iff biff nff off fits etc you almost certainly don t need these read the above item on free image manipulation software get one or more of these packages and look through them chances are excellent that the image converter you were going to write is already there but if you still want one of the format documents many such files are available by anonymous ftp from zamenhof cs rice edu in directory pub graphics formats these files were collected off the net and are believed to be correct this archive includes pixel formats and two and three dimensional object formats the future of this archive is uncertain at the moment as mark hall foo cs rice edu will apparently no longer be maintaining it a second graphics file format archive is now being actively maintained by quincey koziol koziol ncsa uiuc edu the latest version exists at ftp ncsa uiuc edu in misc file formats graphics formats apparently neither of these is complete you might want to check both fits stands for flexible image transport system it s a file format most often used in astronomy despite the name it can contain not only images but other things as well there is a regular monthly fits basics and information posting on sci astro fits read it if you want to know more converting between vector formats a lot of people ask about converting from hpgl to postscript or macdraw to cgm or whatever it is important to understand that this is a very different problem from the image format conversions in item converting one image format to another is a fairly easy problem since once you get past all the file header junk a pixel is a pixel the basic objects are the same for all image formats this is not so for vector formats the basic objects circles ellipses drop shadowed pattern filled round cornered rectangles etc vary from one format to another except in extremely restricted cases it is simply not possible to do a one to one conversion between vector formats there is software for converting to and from cgm files on ftp psc edu the contributor states that it runs on unix ms windows and possibly the mac a better more specific blurb would be most welcome on the other hand it is quite possible to do a close approximation rendering an image from one format using the primitives from another as far as i know no one has put together a general toolkit of such converters but two different hpgl to postscript converters have been posted to comp sources misc check the index on your nearest archive site a related frequent question is how to convert from some vector format to a bitmapped image from postscript to sun raster format or hpgl to x bitmap for example some of the commercial postscript clones for pc s allow you to render to a disk file as well as a printer also the postscript interpreters in the next box and in sun s x news can be used to render to a file if you re clever but in general the answer is no however if someone were to put together a vector to vector conversion toolkit adding a vector to raster converter would be trivial gnu ghostscript from the fsf current version includes drivers for both ppm and gif format files thus it can be used as a postscript to ppm or a postscript to gif filter it implements essentially all of postscript level and alot of display postscript and level how to get pixar films the various john lasseter pixar computer animated shorts are available on video tape you can order them from direct cinema limited film individual price institutional price luxo jr red s dream tin toy knickknack luxo jr red s dream tin toy all tapes are on vhs ntsc add tape for pal format also available tin toy t shirt knickknack d t shirt includes glasses for individual orders add s h for the first tape or shirt for each additional tape or shirt for institutional orders add s h for the first tape for each additional tape foreign shipping add tape or shirt call international fax to charge to your credit card call first to verify prices and availability or just write to direct cinema limited th street santa monica ca allan braunsdorf has this to say at siggraph they were selling a tape with all four shorts for that was a sale price you can get it for slightly more than that normally maybe i believe it s available from renderman retail at pixar s address pixar west cutting blvd richmond ca fax you can obtain a video directly from pixar which contains luxo jr red s dream tin toy and knicknack for plus for shipping they will take your order over the phone or via fax with a major credit card i ordered mine just last week and received it several days later don t expect to be able to rent a copy from your local video store according to the license agreement printed on the back cover of the case it cannot be rented how do i draw a circle as a bezier or b spline curve the short answer is you can t unless you use a rational spline you can only approximate a circle the approximation may look acceptable but it is sensitive to scale magnify the scale and the error of approximation magnifies deviations from circularity that were not visible in the small can become glaring in the large if you want to do the job right consult the article a menagerie of rational b spline circles by leslie piegl and wayne tiller in ieee computer graphics and applications volume number september pages for rough non rational approximations consult the book computational geometry for design and manufacture by i d faux and m j pratt ellis horwood publishers halsted press john wiley for the best known non rational approximations consult the article good approximation of circles by curvature continuous bezier curves by tor dokken morten daehlen tom lyche and knut morken in computer aided geometric design volume numbers combined june pages elsevier science publishers north holland how to order standards documents the american national standards institute sells ansi standards and also iso international standards their sales office is at mailing address is broadway ny ny it helps if you have the complete name and number some useful numbers to know cgm computer graphics metafile is iso gks graphical kernel system is ansi x phigs programmer s hierarchical interactive graphics system is ansi x iges is asme ansi y m language bindings are often separate but related numbers for example the gks fortran binding is x standards in progress are made available at key milestones to solicit comments from the graphical public this includes you ansi can let you know where to order them most are available from global engineering at how to ftp by email there are a number of sites that archive the usenet sources newsgroups and make them available via an email query system you send a message to an automated server saying something like send comp sources unix fbm and a few hours or days later you get the file in the mail in addition there is at least one ftp by mail server send mail to ftpmail decwrl dec com saying help and it will tell you how to use it note that this service has at times been turned off due to abuse how to tell whether a point is within a planar polygon consider a ray originating at the point of interest and continuing to infinity if it crosses an odd number of polygon edges along the way the point is within the polygon if the ray crosses an even number of edges the point is either outside the polygon or within an interior hole formed from intersecting polygon edges this idea is known in the trade as the jordan curve theorem see eric haines article in glassner s ray tracing book above for more information including treatment of special cases another method is to sum the absolute angles from the point to all the vertices on the polygon if the sum is pi the point is inside if the sum is the point is outside however this method is about an order of magnitude slower than the previous method because evaluating the trigonometric functions is usually quite costly code for both methods plus barycentric triangle testing can be found in the ray tracing news vol no available from princeton edu pub graphics rtnews rtnv n z how to tessellate a sphere one simple way is to do recursive subdivision into triangles the base of the recursion is an octahedron and then each level divides each triangle into four smaller ones jon leech leech cs unc edu has posted a nice routine called sphere c that generates the coordinates it s available for ftp on ftp ee lbl gov and princeton edu specific references on ray tracing and global illumination rick speer maintains a cross indexed ray tracing bibliography highlights of this edition i more than citations spanning the period from through november ii papers from all siggraph graphics interface eurographics cg international and ausgraph proceedings through december iii all citations keyworded for easy lookup iv cross indices by keyword and author v glossary of the keywords used the bib is in the form of a postscript file the printout is pages long below is a list of ftp sites and the dirs that contain the file it s named speer raytrace bib ps z and is compressed at most sites site dir wuarchive wustl edu graphics graphics bib rt bib speer karazm math uh edu pub graphics gondwana ecr mu oz au pub papers nic funet fi pub sci papers graphics coral cs jcu edu au graphics papers eric haines erich eye com maintains ray tracing and radiosity global illumination bibliographies these are in refer format and so can be searched electronically a simple awk script to search for keywords is included with each the bibliographies are available at most of the sites listed above and the most current versions are maintained at princeton edu pub graphics papers as raybib and radbib tom wilson wilson cs ucf edu has collected over abstracts from ray tracing related research papers and books the information is essentially in plaintext and latex and troff formatting programs are included this collection is available at most of the sites above as rtabs siggraph information online from steve cunningham and ralph orlick acm siggraph announces its online information site at siggraph org this site now provides siggraph information via both anonymous ftp and an electronic mail archive server the anonymous ftp service is very standard and the ftp directory includes both conference and publications subdirectories to retrieve information by electronic mail send mail to archive server siggraph org and in the subject or the body of the message include the message send followed by the topic and subtopic you wish a good place to start is with the command send index which will give you an up to date list of available information siggraph panels proceedings available from steve cunningham and bob judd acm siggraph announces the availability of the siggraph panels proceedings at the siggraph org site the proceedings are available in three formats text ascii rtf rich text format suitable for many word processors word ms word for the macintosh they may be retrieved from siggraph org in two ways by anonymous ftp change to one of the directories publications s panels proceedings text rtf word the text and rtf files may be downloaded in ascii mode while the word files are stored in macbinary format and must be downloaded in binary mode each directory contains a table of contents file toc that describes the contents of each panel file by electronic mail send mail to archive server siggraph org you can retrieve either the text or rtf files we suggest that you first retrieve the index files by putting one of the messages send panel txt index send panel rtf index in the subject or body of the message you will get the necessary information to retrieve the actual transcript files graphics mailing lists there are a variety of graphics related mailing list out there each covering either a single product or a single topic i have been an active participant in one of these for some time now and find the focus and expertise which can be brought to bear on an isolated topic to be nothing short of amazing please send me the appropriate information if you have any others you would like to see added name imagine mailing list description discussion forum for users of the imagine d rendering and animation package by impulse inc platforms amiga ibm subscription imagine request email sp paramax com posting imagine email sp paramax com name dctv mailing list description discussion forum for users of the digital creations dctv box software and file formats platforms amiga subscription dctv request nova cc purdue edu posting dctv nova cc purdue edu name rayshade users mailing list description discussion forum for users of the rayshade raytracer platforms most unix boxes amiga mac ibm subscription rayshade request cs princeton edu posting rayshade users cs princeton edu name lightwave d software for toaster mailing list description discussion forum for users of lightwave the video toaster modelling and rendering package platforms amiga subscription lightwave request bobsbox rent com with subscribe lightwave l in your message posting lightwave bobsbox rent com name pov mailing list description discussion forum for dkbtrace and pov renderers platforms unix subscription listserv trearn bitnet posting dkb l trearn bitnet name mailing list for massive parallel rendering description same platforms unix subscription mp render request icase edu posting mp render icase edu specific references on file formats graphics file formats david kay and john levine windcrest mcgraw hill isbn paper isbn hardcover isbn paper comments formats no software this is good imho i prefer books which are non platform dependent questions about this book may be sent to gbook iecc cambridge ma us what about gif gif stands for graphics interchange format it is portable and usable upon a wide variety of platforms it is quite limited in some ways yes the keeper of the faq has some opinions after all and in fact i don t like it much however it looks to me like the most frequently asked question which was not previously covered in this list the following is a list of newsgroups and the like where one could go to find out about gif subject alt binaries pictures faq general info subject alt binaries pictures faq os specific info newsgroups alt binaries pictures d alt binaries pictures misc alt binaries pictures utilities alt binaries pictures fractals alt binaries pictures fine art d news answers available in the indicated usenet newsgroup s or via anonymous ftp from pit manager mit edu in the files pub usenet news answers pictures faq part pub usenet news answers pictures faq part also available from mail server pit manager mit edu by sending a mail message containing any or all of send usenet news answers pictures faq part send usenet news answers pictures faq part send a message containing help to get general information about the mail server also you could check out the resources described in sections and above for more information what is morphing warping is the deformation of an image by mapping each pixel to a new location morphing is blending from one image or object to another one valerie hall has written an excellent introduction to warping and morphing this is available for anonymous ftp from marsh cs curtin edu au in the directory pub graphics bibliography morph there are three files morph intro ps z postscript version many pictures m morph intro txt z text version m responses z responses to morphing questions the files are compressed so you must use binary transfer and uncompress them afterwards how to ray trace height fields height fields are a special case in ray tracing they have a number of uses such as terrain rendering and some optimization is possible thus they get their own faq section note that further references can no doubt be located via the ray tracing bibs in section above the following paper seems to be the definitive reference f kenton musgrave grid tracing fast ray tracing for height fields july musg ps z this is available as research report yaleu dcs rr from yale university it s also in the siggraph fractal modeling in d computer graphics and imaging course notes and best of all it s available on the net nic funet fi pub sci papers musg ps z weedeater math yale edu pub papers musg ms z princeton edu pub graphics papers musg ms z coral cs jcu edu au graphics papers musg ps z gondwana ecr mu oz au pub papers musg ms z and musg ps z an implementation of this paper may be found in rayshade another paper exists a david w paglieroni a sidney m petersen t parametric height field ray tracing j proceedings of graphics interface i canadian information processing society c toronto ontario d may p and still one more musgrave kolb and mace the synthesis and rendering of eroded fractal terrains computer graphics vol no siggraph procedings p how to find the area of a d polygon the area of a triangle is given by in c notation area x y x y x y x y x y x y and the area of a planar polygon is given by area for i i n i area x i y i x i y i area x n y x y n area if the area is a negative number the polygon or triangle is clockwise if positive it is counterclockwise from ronald golman s gem in graphics gems ii see section above area of planar polygons and volume of polyhedra the area of a polygon p p p pn not in the x y plane is given by area polygon n sigma pk x pk where n is the unit vector normal to the plane and p is a polygonal vertex the represents the dot product operator and the x represents the cross product operator sigma represents the summation operator represents the absolute value operator pn is equal to p how to join acm siggraph probably the easiest way to join acm siggraph is to trot over to your local technical library and find a copy of communications of the acm somewhere within the first few pages will be an application blank fill it out and mail it in acm membership for students costs voting or associate membership yearly siggraph student membership costs an additional for voting or associate members also yearly to get tog transactions on graphics it s another for students and for voting or associate members if you just want to join siggraph without joining acm it ll cost you no student discount there are surcharges for overseas airmailing of publications acm member services may be contacted via email at acmhelp acmvm bitnet their phone number is fax number snailmail address acm po box church street station new york new york siggraph will be held in anaheim california at the anaheim convention center just up the street from disneyland on august where can i find mri and ct scan volume data volume data sets are available from the university of north carolina at omicron cs unc edu in pub softlab chvrtd commerical use is prohibited head data a slice mri data set of a human head knee data a slice mri data set of a human knee hipip data the result of a quantum mechanical calculation of a sod data of a one electron orbital of hipip an iron protein sod data an electron density map of the active site of sod superoxide dismutase ct cadaver head data a slice mri data set of a ct study of a cadaver head mr brain data a slice mri data set of a head with skull partially removed to reveal brain rna data an electron density map for staphylococcus aureus ribonuclease specific references on spatial data structures including quadtrees and octrees h samet the design and analysis of spatial data structures addison wesley reading ma isbn h samet applications of spatial data structures computer graphics image processing a nd gis addison wesley reading ma isbn where can i get a program to plot xy z data or f x data gnuplot is a command driven interactive data function plotting program it runs on just about any machine and is very flexible in terms of supported output devices the official north american distribution site for the latest version is dartmouth edu in pub gnuplot more information is available from the usenet newsgroup comp graphics gnuplot and its faq graphics gnuplot faq ace gr xmgr motif xvgr xview is a data function plotting tool for workstations or x terminals using x available from ftp ccalmr ogi edu in ccalmr pub acegr robotx robot is a general purpose plotting and data analysis program requires xview x terminal or workstation available from sunsite unc edu in pub academic data analysis xgraph is a popular two dimensional plotting program that accepts data in a form similar to the unix program graph and displays line graphs scatter plots or bar charts on an x display available from ic berkeley edu in pub drawplot is a program for drawing d plots on x x windows sunview displays or hp terminals available from xcf berkeley edu in src local specific references on pex and phigs pexlib programming manual tom gaskins pages o reilly associates isbn pexlib reference manual edited by steve talbott pages o reilly associates isbn phigs programming manual tom gaskins pages o reilly associates isbn softcover isbn casebound phigs reference manual edited by linda kosko pages o reilly associates isbn siggraph online bibliography project the acm siggraph online bibliography project is a database of over unique computer graphics and computational geometry references in bibtex format available to the computer graphics community as a research and educational resource the database is located at siggraph org users may download the bibtex files via ftp and peruse them offline or telnet to siggraph org and log in as biblio and interactively search the database for entries of interest by keyword additions corrections suggestions may be directed to the admin bibadmin siggraph org john t grieggs telos jet propulsion laboratory oak grove drive pasadena ca m s uucp cit vax elroy chas jpl devvax grieggs arpa jpl devvax grieggs cit vax arpa
