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From: Sean Baxter <spec@ri...>  20021204 23:41:33

I wrote code for planetary chunked LOD terrain. Pictures are here: http://spec.winprog.org/ Uses a heavilymodified version of Lindstrom's latest terrain LOD = algorithm for viewindependent simplification (uses an error metric in = spherical coordinates rather than planar coordinates, for one thing). = Lindstrom's embeddedquadtree file indexing scheme makes producing = refinements at the preprocessing stage extremely fast (since it was = intended for runtime use). I produce Thatcheresque chunked LOD = quadtrees, but six of them (think of a cube centered in a sphere.. each = face is a terrain). The preprocessor will produce chunked LOD quadtrees = of arbitrary topology, so if you have local data for a particular area, = you can make the quadtree very deep in that region so you can keep = zooming in and keep getting detail. Renders quite fast, even with these high triangle counts. Am rendering = indexed triangle strips, which are stored and kept in static buffers in = the D3D default (video memory) pool. So minimal CPU use. The vertex = shader scales the terrain at runtime with respect to the WGS84 = reference spheroid, so you can better see surface detail. The ribs that = you see in the wire frame shots are crackfilling triangle thongs. For data I used the GLOBE 30arcsecond DEM and NASA's 30arcsecond Visible = Earth. The preprocessor samples both DEM and texture data. It supports = multiple data sources, so you can dump in whatever data you have, choose = quadtree topologies to get the detail where you want it, and everything = comes out in the mix. Datums (different reference spheroids) and = projections (well, just UTM at the moment, but that's the meanest of = them all) are handled correctly. Some changes to the preprocessor are = needed to make integrating small regions of very high res data more = space efficient... This is a huge improvement over having to fiddle = around to get your initial data as a 2^n + 1sized grid. Abstraction is = good. All in all I am quite satisfied. =20 =3D) .sean baxter 
From: Jay Stelly <J<ay@va...>  20021204 22:04:22

> Actually, my math shows that the optimal OBB of an octahedron > does have a > plane parallel to the octahedron's face. If you consider the > equilateral > unit octahedron, then the OBB that Jay is proposing has volume You're right, an equilateral octohedron isn't enough because it's identical to the 2d case because of symmetry. Intuitively, it seems like you could do a nonuniform scale to the octohedron (applied the axes between pairs of verts) to make the optimal OBB be coplanar with edges; it's like separating axis because the OBB that isn't planar with the faces bevels off the long pointy bits that will get created by the coplanar box; but that's just a thought experiment. I'll try to turn it into a concrete example. Jay 
From: Charles Bloom <cbloom@cb...>  20021204 21:28:53

Actually, my math shows that the optimal OBB of an octahedron does have a plane parallel to the octahedron's face. If you consider the equilateral unit octahedron, then the OBB that Jay is proposing has volume (2/3) * sqrt(6) (about 1.633) While the OBB that's parallel to one of the faces has volume (8/11) * ( sqrt(11/12) + 5 / sqrt(11*12) ) (about 1.013) It's possible I made an error, as I just cooked those numbers up quickly, but if you draw some pictures it's pretty clear that the later OBB is better. For reference : http://mathworld.wolfram.com/Octahedron.html At 12:01 PM 12/4/2002 0800, Jay Stelly wrote: >I haven't looked at the galaxy code, but there are cerainly cases where a >face of the optimal OBB is not coplanar with any of the triangles on the >convex hull. Think of cases where the OBB face's plane contains only one >edge or vertex of the convex hull. Maybe this is what Christer is referring >to? Think of the optimal OBB of an octahedron as an example. > >Jay > > > > Original Message > > From: Charles Bloom [mailto:cbloom@...] > > Sent: Wednesday, December 04, 2002 11:14 AM > > To: gdalgorithmslist@... > > Subject: RE: [Algorithms] Generating a (near) optimal OBB from set of > > points. [spam?][bcc][fake adr] > > > > > > > > Interesting; do you have a reference to that? I suppose it's > > related to > > the separating axis theorem; in constructing an OBB, you need > > to consider > > all the same axes that you would if doing a separatingaxis test. I'm > > having a very hard time thinking of an example case where > > that applies... > > > > At 10:44 AM 12/4/2002 0800, > > christer_ericson@... wrote: > > > > >While a minimum area bounding box in 2D has an edge coinciding with > > >an edge of the convex polygon it encloses, a minimum volume OBB in > > >3D doesn't necessarily have a face aligned with one of the faces of > > >the convex polyhedron it encloses. The case missed is one where three > > >OBB faces each contain an edge from the polyhedron. So, "exactly > > >optimal OBB's" is too strong a statement, but "pretty good OBB's" > > >would be correct. > > > > > > > >This SF.net email is sponsored by: Microsoft Visual Studio.NET >comprehensive development tool, built to increase your >productivity. Try a free online hosted session at: >http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en >_______________________________________________ >GDAlgorithmslist mailing list >GDAlgorithmslist@... >https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist >Archives: >http://sourceforge.net/mailarchive/forum.php?forum_id=6188  Charles Bloom cbloom@... http://www.cbloom.com 
From: Adam Paul Coates <acoates@st...>  20021204 21:06:27

This will probably depend partly on the actual terrain algorithm you decide to use. In addition to Thatcher's section on LOD (paging the quadtree data is a little tricky, but can look really nice, since you can "partially" page in areas of low detail) you can also go the easy route: check out William de Boer's paper on 'geomipmapping'. He doesn't give too many details, but if you're willing to accept many of the shortcomings of the algorithm (simplyminded, as it is) it's almost trivial to implement a simple paging system (since the chunks themselves can just be your pages) and you can adjust the ordering of vertices in the files or whatever your data source is to allow much nicer streaming afterward. Here's the link: http://www.flipcode.com/tutorials/geomipmaps.pdf Good luck, Adam C. On Wed, 4 Dec 2002, Weston Fryatt wrote: > I'm looking for ideas, and papers on how to page in sections of Terrain to create a continues flowing world. > > Thanks > Weston Fryatt 
From: Jon Watte <hplus@mi...>  20021204 20:53:14

If you have nonuniform scale, then this will actually slant the normal in the wrong direction, unless you use the inverse transpose matrix. If you have uniform scale, then the transformed normals will also be scaled, and come out the wrong length, which will affect lighting unless you pay the cost to renormalize. Of course, if you have HT&L hardware, the cost of normalizing is usually very small; especially if you're fill bound (which you should be :) Cheers, / h+ > thanx for your help. I think I got everything. What I don't understand is > why is scaling a problem? 
From: Tony Cox <tonycox@mi...>  20021204 20:45:37

Think about it. If you nonuniformly scale, the normals don't get transformed the same way. Draw a couple of examples on paper to convince yourself. To properly transform normals when you have an abitrary matrix, you need to multiply by the inverse transpose. (You'll note that in the case of an orthogonal matrix, i.e. one with just rotations, the inverse transpose is exactly the matrix you started with  as expected). Tony Cox  Development Lead, Hockey Microsoft Games Studios  Sports Original Message From: Dirk Gregorius [mailto:dirk@...]=20 Sent: Wednesday, December 04, 2002 12:35 PM To: gdalgorithmslist@... Subject: Re: [Algorithms] Transforming normals Hey everybody, thanx for your help. I think I got everything. What I don't understand is why is scaling a problem? Dirk 
From: Dirk Gregorius <dirk@di...>  20021204 20:33:29

Hey everybody, thanx for your help. I think I got everything. What I don't understand is why is scaling a problem? Dirk 
From: Thatcher Ulrich <tu@tu...>  20021204 20:05:49

On Wed, 4 Dec 2002, Weston Fryatt wrote: > I'm looking for ideas, and papers on how to page in sections of > Terrain to create a continues flowing world. My stuff's at http://tulrich.com/geekstuff/chunklod.html The everythingyouwantedtoknowaboutterrain site is http://www.vterrain.org Thatcher 
From: Jay Stelly <J<ay@va...>  20021204 19:58:25

I haven't looked at the galaxy code, but there are cerainly cases where a face of the optimal OBB is not coplanar with any of the triangles on the convex hull. Think of cases where the OBB face's plane contains only one edge or vertex of the convex hull. Maybe this is what Christer is referring to? Think of the optimal OBB of an octahedron as an example. Jay > Original Message > From: Charles Bloom [mailto:cbloom@...] > Sent: Wednesday, December 04, 2002 11:14 AM > To: gdalgorithmslist@... > Subject: RE: [Algorithms] Generating a (near) optimal OBB from set of > points. [spam?][bcc][fake adr] > > > > Interesting; do you have a reference to that? I suppose it's > related to > the separating axis theorem; in constructing an OBB, you need > to consider > all the same axes that you would if doing a separatingaxis test. I'm > having a very hard time thinking of an example case where > that applies... > > At 10:44 AM 12/4/2002 0800, > christer_ericson@... wrote: > > >While a minimum area bounding box in 2D has an edge coinciding with > >an edge of the convex polygon it encloses, a minimum volume OBB in > >3D doesn't necessarily have a face aligned with one of the faces of > >the convex polyhedron it encloses. The case missed is one where three > >OBB faces each contain an edge from the polyhedron. So, "exactly > >optimal OBB's" is too strong a statement, but "pretty good OBB's" > >would be correct. > > 
From: Jon Watte <hplus@mi...>  20021204 19:53:42

> how do I transform the normals of a skinned mesh using skeletonbased > animation? IF you do a 4x4 transform AND you can put in "1" for the w for your position AND you can put in "0" for the w for your normal AND your animations contain no scale or skew THEN you can just transform normals just like you'd transform the position If you do, say, 4x3, but there's still no scale or skew, then you can use the 3x3 of the position transform. Else, you have to find the inverse transpose of your position transform matrix, and use that for the normals, which results in twice the necessary matrix space. Because we do this on the CPU (no vertex shader requirement) we wrote a very efficient SSE 4x4 transform function, align/pad the vertex structure to fill the requirements outlined up top, and just let it rip (writing to AGP memory on the backside, to avoid unnecessary copies). This means you have to put your vertex color and texture data in a separate vertex buffer/stream, and your skinning information (vertex/weight data items) in cacheable memory in a third place. But it works really well. If you have a tangent space, the rules for the binormal and/or tanget are the same as for normals. Cheers, / h+ 
From: <christer_ericson@pl...>  20021204 19:48:27

Charles Bloom wrote: >Interesting; do you have a reference to that? This paper outlines the basic problem, including showing that a box face isn't necessarily aligned with a face from the convex polyhedron: O'Rourke, Joseph. Finding minimal enclosing boxes. Internat. J. Comput. Inform. Sci. Vol 14, 1985, pp 183199 It describes an O(n^3) algorithm for the minimum volume box of a convex polyhedron. I have a copy of the paper somewhere, but I'm not sure where it's at right now, so I'm afraid I can't give more details since it's just off the top of my head. Christer Ericson Sony Computer Entertainment, Santa Monica 
From: Charles Bloom <cbloom@cb...>  20021204 19:15:00

Interesting; do you have a reference to that? I suppose it's related to the separating axis theorem; in constructing an OBB, you need to consider all the same axes that you would if doing a separatingaxis test. I'm having a very hard time thinking of an example case where that applies... At 10:44 AM 12/4/2002 0800, christer_ericson@... wrote: >While a minimum area bounding box in 2D has an edge coinciding with >an edge of the convex polygon it encloses, a minimum volume OBB in >3D doesn't necessarily have a face aligned with one of the faces of >the convex polyhedron it encloses. The case missed is one where three >OBB faces each contain an edge from the polyhedron. So, "exactly >optimal OBB's" is too strong a statement, but "pretty good OBB's" >would be correct.  Charles Bloom cbloom@... http://www.cbloom.com 
From: Weston Fryatt <wfryatt@ml...>  20021204 19:10:52

I'm looking for ideas, and papers on how to page in sections of Terrain = to create a continues flowing world. Thanks Weston Fryatt 
From: <christer_ericson@pl...>  20021204 18:45:35

Charles Bloom wrote: >There's code to find OBB's in Galaxy3 > >http://www.cbloom.com/3d/galaxy3/index.html > >They are exactly optimal OBB's, found in O(N*H), where H is the number >of planes in the convex hull of an object, N is the number of polys. >Typically H ~ log(N). While a minimum area bounding box in 2D has an edge coinciding with an edge of the convex polygon it encloses, a minimum volume OBB in 3D doesn't necessarily have a face aligned with one of the faces of the convex polyhedron it encloses. The case missed is one where three OBB faces each contain an edge from the polyhedron. So, "exactly optimal OBB's" is too strong a statement, but "pretty good OBB's" would be correct. Christer Ericson Sony Computer Entertainment, Santa Monica 
From: John Connors <jconnors@re...>  20021204 18:44:18

Don't. It's not worth it. If you are skinning a mesh with more than one bone influence per vertex, just transform by the rotation component of the transform associated with the bone which has the most influence on the vertex associated with the normal. Faster, and looks as good. Of course, this assumes there is no scaling in your pipeline..if there is, then good luck :) Original Message From: Dirk Gregorius [mailto:dirk@...] Sent: 04 December 2002 18:00 To: gdalgorithmslist@... Subject: [Algorithms] Transforming normals Hi, how do I transform the normals of a skinned mesh using skeletonbased animation? Dirk  This SF.net email is sponsored by: Microsoft Visual Studio.NET comprehensive development tool, built to increase your productivity. Try a free online hosted session at: http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en _______________________________________________ GDAlgorithmslist mailing list GDAlgorithmslist@... https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188 Virus scanned and cleared ok 
From: Jason Maynard <jmaynard@li...>  20021204 18:28:45

Normals should be done the same way as transforming the vertex positions only without using the translation portion of the bone matices. Jason  Original Message  From: "Dirk Gregorius" <dirk@...> To: <gdalgorithmslist@...> Sent: Wednesday, December 04, 2002 9:59 AM Subject: [Algorithms] Transforming normals > Hi, > > how do I transform the normals of a skinned mesh using skeletonbased > animation? > > Dirk > > > >  > This SF.net email is sponsored by: Microsoft Visual Studio.NET > comprehensive development tool, built to increase your > productivity. Try a free online hosted session at: > http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en > _______________________________________________ > GDAlgorithmslist mailing list > GDAlgorithmslist@... > https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_id=6188 
From: Dirk Gregorius <dirk@di...>  20021204 17:58:24

Hi, how do I transform the normals of a skinned mesh using skeletonbased animation? Dirk 
From: Jon Watte <hplus@mi...>  20021204 17:55:14

We're having a similar problem, and I haven't come up with any good references for it. We found a sufficient heuristic and left it at that, so I don't think we spent more time on it anytime lately. Here's some thoughts: If you can assume that the pushers are planes, and you get the "out" normals from the planes, then you can constrain the cone within which you can push the player by looking at these planes, because they all cut out a halfspace from the potential pushing directions. If you have a sufficient number of planes (at least 4) that are sufficiently oriented, then the space enclosing the player may not actually let the player "escape" and in that case, you detect a crush. You may also wish to use an implicit plane created by not allowing the player to be pushed more than X meters per time step  if the solution would push the player more than that, instead detect crushing (or pinching, if there's a difference). An iterative solution might involve first calculating a solution using only known contact points, then run collision on the bounding volume of the movement created that way, and then recreate a solution including the new data if you find that it wasn't valid (pushing through walls, etc). Another thought is to collect all surfaces within pushing distance up front, but then you get into problems with what to do with surfaces that aren't actually colliding yet, but could be after sliding. Anyway, I'll be very interested if someone has a solution better than just heuristics to this problem. I believe there's a linear programming solution formulation for this problem, actually, but I wonder if that can be made to run fast enough... anyone have pointers to an implementation, or just description? Cheers, / h+ Original Message From: gdalgorithmslistadmin@... [mailto:gdalgorithmslistadmin@...]On Behalf Of John Bustard Sent: Wednesday, December 04, 2002 2:28 AM To: gdalgorithmslist@... Subject: [Algorithms] Animation and Physics Hi everyone, I am currently looking into the design of a dynamics/physics system for our next game. It raises a bunch of issues to do with animation and physics and I was wondering if you guys could guide me in the right direction. The problem is this: We have large animating scenes that move into the character. This can cause situations where the character can be crushed as well as situations where the character is pushed out of the way. The system we have for the current game involves starting with an interpenetrating situation and iteratively pushing the character out of each volume in turn. This isn't very robust and requires a lot of fiddling with the level design to make it work. I am trying to find a better solution for the next game and I am looking into a system that finds a free space to put the character into rather than pushing them out. For example by testing positions in a grid around the current position. This has problems as well like forcing characters through walls, not sending the character in the right direction when pushed, and not rotating the character as they are pushed. Has anyone tackled these sort of problems before or know of any research on finding spaces for objects? Thanks, John Bustard Just Add Monsters Oh yeah and all of this stuff is my opinion not that of Just Add Monsters. (Damn the man) 
From: Charles Bloom <cbloom@cb...>  20021204 16:55:55

There's code to find OBB's in Galaxy3 http://www.cbloom.com/3d/galaxy3/index.html They are exactly optimal OBB's, found in O(N*H), where H is the number of planes in the convex hull of an object, N is the number of polys. Typically H ~ log(N). At 10:06 AM 12/4/2002 0600, Gribb, Gil wrote: > Typically people use the eigenvectors from the covariance matrix. >There is no real formal justification for this, but it certainly finds >mostly planar and mostly linear point sets. Gil  Charles Bloom cb@... http://www.cbloom.com 
From: Gribb, Gil <ggribb@ra...>  20021204 16:06:11

Typically people use the eigenvectors from the covariance matrix. There is no real formal justification for this, but it certainly finds mostly planar and mostly linear point sets. Gil Original Message From: John White [mailto:johnw@...] Sent: Wednesday, December 04, 2002 9:38 AM To: gdalgorithmslist@... Subject: [Algorithms] Generating a (near) optimal OBB from set of points. [spam?][bcc][fake adr] Hi, I'm looking for some simple to use code (or theory) to generate a good Oriented Bounding Box from a set of points (in R3). Ideally the result I'll get back will either be a set of 8 points or an AABB with a rotation matrix. Google doesn't help. I found some code on wild magic but it looks like it'll need a serious amount of work to get the code to integrate with my own code base plus I'll need to use the code in a commercial product. Thanks for any help or pointers. John  This SF.net email is sponsored by: Microsoft Visual Studio.NET comprehensive development tool, built to increase your productivity. Try a free online hosted session at: http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en _______________________________________________ GDAlgorithmslist mailing list GDAlgorithmslist@... https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188 
From: John White <johnw@de...>  20021204 15:41:19

Hi, I'm looking for some simple to use code (or theory) to generate a good Oriented Bounding Box from a set of points (in R3). Ideally the result I'll get back will either be a set of 8 points or an AABB with a rotation matrix. Google doesn't help. I found some code on wild magic but it looks like it'll need a serious amount of work to get the code to integrate with my own code base plus I'll need to use the code in a commercial product. Thanks for any help or pointers. John 
From: David Lam  Tokamak <dlam@to...>  20021204 13:23:16

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From: Awen Limbourg <alimbourg@ed...>  20021204 13:02:38

Jim's proposal depends on the waypoint granularity (heavy): a long straight road induces a few waypoints; falling boulders would split the entity's road in three, and... what ? And introducing more waypoints is not a 'strong' solution. (sufficient ?) If events of that type (path obstructions) are not strongly scenarized, you cannot foresee  as a scenaric coder  very well all your 'boulder' configurations and put your waypoints accordingly. A very few games are demolishing their scenery (Red Faction which 'opens' ways and never 'closing' them IIRC). It's painful scenarically speaking, and in our case verboten :) Awen EdenStudios Message d'origine De : gdalgorithmslistadmin@... [mailto:gdalgorithmslistadmin@...]De la part de John Bustard Envoyé : mercredi 4 décembre 2002 12:43 À : gdalgorithmslist@... Objet : Re: [Algorithms] Animation and Physics Thanks Jim, That's a great idea. We do have quite a bit of falling, and sliding animating objects that appear within the waypoints but the AI needs to navigate them as well. Maybe the solution is to find ways of rapidly altering the waypoints around these objects to help the ai and the collision. Also I think finding a free space in a set of volumes is the sort of nicely constrained problem ripe for optimisations and research papers, universities could do with some research wish lists. John Bustard Just Add Monsters Oh yeah and all of this stuff is my opinion not that of Just Add Monsters. (Damn the man)  Original Message  From: "Jim Offerman" <j.offerman@...> To: <gdalgorithmslist@...> Sent: Wednesday, December 04, 2002 10:51 AM Subject: Re: [Algorithms] Animation and Physics > Hey John, > > > Has anyone tackled these sort of problems before or know of any research > > on finding spaces for objects? > > Just a thought (as I haven't actually tried this), but if you have > stored any waypoint information for your computer controlled entities, > which I'm assuming you have, you could have the physics engine always > push characters in the direction of the nearest waypoint. > > You could even keep track of the last waypoint that the player passed > over and use that to decide which waypoint should be the target of the > push in ambigous situations. > > For example (ascii art warning): > > A > X wall > B C > > A, B and C are waypoints. > X is the player's current position. > > Assuming that the player has just passed over C, the system would push > the player towards B instead of A, since B is reachable from C while A > is not, since it's on the other side of the wall. > > Should work, right? > > HTH, > > Jim Offerman > Crevace Games > http://www.crevace.com > > > > > > > > >  > This SF.net email is sponsored by: Microsoft Visual Studio.NET > comprehensive development tool, built to increase your > productivity. Try a free online hosted session at: > http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en > _______________________________________________ > GDAlgorithmslist mailing list > GDAlgorithmslist@... > https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_id=6188 > >  This SF.net email is sponsored by: Microsoft Visual Studio.NET comprehensive development tool, built to increase your productivity. Try a free online hosted session at: http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en _______________________________________________ GDAlgorithmslist mailing list GDAlgorithmslist@... https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188 
From: John Bustard <John.Bustard@JustAddMonsters.com>  20021204 11:41:11

Thanks Jim, That's a great idea. We do have quite a bit of falling, and sliding animating objects that appear within the waypoints but the AI needs to navigate them as well. Maybe the solution is to find ways of rapidly altering the waypoints around these objects to help the ai and the collision. Also I think finding a free space in a set of volumes is the sort of nicely constrained problem ripe for optimisations and research papers, universities could do with some research wish lists. John Bustard Just Add Monsters Oh yeah and all of this stuff is my opinion not that of Just Add Monsters. (Damn the man)  Original Message  From: "Jim Offerman" <j.offerman@...> To: <gdalgorithmslist@...> Sent: Wednesday, December 04, 2002 10:51 AM Subject: Re: [Algorithms] Animation and Physics > Hey John, > > > Has anyone tackled these sort of problems before or know of any research > > on finding spaces for objects? > > Just a thought (as I haven't actually tried this), but if you have > stored any waypoint information for your computer controlled entities, > which I'm assuming you have, you could have the physics engine always > push characters in the direction of the nearest waypoint. > > You could even keep track of the last waypoint that the player passed > over and use that to decide which waypoint should be the target of the > push in ambigous situations. > > For example (ascii art warning): > > A > X wall > B C > > A, B and C are waypoints. > X is the player's current position. > > Assuming that the player has just passed over C, the system would push > the player towards B instead of A, since B is reachable from C while A > is not, since it's on the other side of the wall. > > Should work, right? > > HTH, > > Jim Offerman > Crevace Games > http://www.crevace.com > > > > > > > > >  > This SF.net email is sponsored by: Microsoft Visual Studio.NET > comprehensive development tool, built to increase your > productivity. Try a free online hosted session at: > http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en > _______________________________________________ > GDAlgorithmslist mailing list > GDAlgorithmslist@... > https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_id=6188 > > 
From: Jamie Fowlston <jamief@qu...>  20021204 11:36:36

i'll give that a shot, thanks. Original Message From: gdalgorithmslistadmin@... [mailto:gdalgorithmslistadmin@...]On Behalf Of Garett Bass Sent: 03 December 2002 20:23 To: gdalgorithmslist@... Subject: RE: [Algorithms] coefficients of friction and restitution The CRC Handbook of Chemistry and Physics can be had used from Amazon.com for $40. Original Message From: gdalgorithmslistadmin@... [mailto:gdalgorithmslistadmin@...]On Behalf Of Jamie Fowlston Sent: Tuesday, December 03, 2002 12:43 PM To: gdalgorithmslist@... Subject: [Algorithms] coefficients of friction and restitution hi all, anyone got any idea where i can find a big table of coefficients of friction (static and kinetic) and restitution for a variety of (pairs of) (everyday) materials? there seem to be a fair few websites out there with coefficients of friction for a limited range of fairly sane materials, but almost nothing on coefficients of restitution.... plus, if it's not in a book costing ?200+ (e.g. CRC Handbook of Physical Quantities), that's a bonus :) but if anyone knows that the CRC book has good entries for restitution as well as friction, i might persuade the company to shell out :) jamie  This SF.net email is sponsored by: Microsoft Visual Studio.NET comprehensive development tool, built to increase your productivity. Try a free online hosted session at: http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en _______________________________________________ GDAlgorithmslist mailing list GDAlgorithmslist@... https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188  This SF.net email is sponsored by: Microsoft Visual Studio.NET comprehensive development tool, built to increase your productivity. Try a free online hosted session at: http://ads.sourceforge.net/cgibin/redirect.pl?micr0003en _______________________________________________ GDAlgorithmslist mailing list GDAlgorithmslist@... https://lists.sourceforge.net/lists/listinfo/gdalgorithmslist Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188 