Hi guys, thanks so much for your recent help with my collision detection problems. I just have one more thing then I think I've got all I need to start coding it up. I have two Axis Aligned Bounding Boxes. One is stationary. One is moving (the reason for this is that it simplifies things - 2 boxes moving relative to each other can be considered as one stationary and the other moving) I have 2 questions, but 2 is more important cos it assumes you know the answer to 1) Now I have a "velocity vector" for the moving box (i.e it moves in a certain direction at x meters per second) 1) Now, given time t, how can I tell if the two boxes will intersect? The problem here is not *are* they intersecting but *will* they? For example, on the way from the starting position of the moving box, to its end position, it may pass OVER and no longer be touching the stationary box. It which case it will appear as if no "collision" has occurred. I know how to do this for circles. (this : http://www.gamasutra.com/features/20020118/vandenhuevel_01.htm article explains how) That is, given a stationary circle and a moving circle with velocity v, I can work out how long it is before they collide. 2) What I need to know, is how to do this for boxes, or rather rectangles. I hope this makes sense..... Thanks again Dean

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4/6/2005 12:48:27 AM

In article <vlG4e.7026$JO6.6920@newsfe6-win.ntli.net>, nospam@nospam.com says... > 1) Now, given time t, how can I tell if the two boxes will intersect? > That is, given a stationary circle and a moving circle with velocity v, I > can work out how long it is before they collide. > > 2) What I need to know, is how to do this for boxes, or rather rectangles. > > I hope this makes sense..... I assume that the boxes are not already intersecting. A simple if uneconomical solution would to test the trajectories of all eight corners against the four edges of the other box, and find the first collision. This will give you the answer unless the boxes meet along parallel edges. To eliminate the case of parallel edges, a simple if sleazy solution is to tilt one box by a thousandth of a degree. Or you can work out a proper test for a 'parallel' intersection. (Of course if you know the boxes are parallel, you can probably simplify the whole solution quite a bit.) - Gerry Quinn

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4/6/2005 9:34:18 AM

Dean Ware wrote: > Hi guys, > > thanks so much for your recent help with my collision detection problems. > > I just have one more thing then I think I've got all I need to start coding > it up. > > I have two Axis Aligned Bounding Boxes. One is stationary. One is moving > (the reason for this is that it simplifies things - 2 boxes moving relative > to each other can be considered as one stationary and the other moving) > > I have 2 questions, but 2 is more important cos it assumes you know the > answer to 1) > > > Now I have a "velocity vector" for the moving box (i.e it moves in a certain > direction at x meters per second) > > > > 1) Now, given time t, how can I tell if the two boxes will intersect? Maintain axis-sorted lists of the bounding boxes in three axes. Change of relative position in the list will tell you of possible intersections. Only then do you run the box-against-box test. This works fine for very large numbers of boxes. You should be able to handle 10,000 to 100,000 moving objects without any problems. This algorithm first appeared in I-COLLIDE. It's in the literature and there's code available. (You'll want to rewrite it; I-COLLIDE was derived from a LISP program and predates collection libraries, so there's too much low-level pointer manipulation.) I-COLLIDE only detected actual box overlap. But with some additional work, you can detect potential fly-throughs, which is what you're asking for. We used an improved version in Falling Bodies. John Nagle Animats

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4/6/2005 6:59:59 PM

In article <PkW4e.10363$FN4.9195@newssvr21.news.prodigy.com>, nagle@animats.com says... > [...] This algorithm first appeared in I-COLLIDE. Actually Baraff described the basic algorithm ealier. -- Christer Ericson http://realtimecollisiondetection.net/

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4/7/2005 5:02:07 AM

Known: P and Q, two points on the infinite length line L. Wanted: segment l=(p,q) of L that intersects a box specified by x,y,w,h. All the algorithms I have seen so far require the (p,q) segment apriori, but I only have P and Q. L is to be a crease in a paper folding application (java). I hope to use segment l and the box to create java2d areas that are intersections or subtractions of a subject area. One of the areas would be flipped about the crease to emulate a folding action. -- Richard A. DeVenezia "Richard A. DeVenezia" <radevenz@ix.netcom.com> wrote in message ...

Given two bounding boxes A and B. How to find if A and B intersect or overlap? Thanks! -Swathi On Tuesday, December 3, 2013 2:27:04 PM UTC-8, sparklingduce wrote: > Given two bounding boxes A and B. How to find if A and B intersect or overlap? Thanks! > > > > -Swathi I tried the command dbBBoxIntersect. It says "undefined function". Thanks! On Tuesday, December 3, 2013 4:27:04 PM UTC-6, sparklingduce wrote: > Given two bounding boxes A and B. How to find if A and B intersect or overlap? Thanks! > > > > -Swathi On Wednesday, ...

Hi everybody, I would like to obtain max and min dimensions in each X,Y,Z of an object I visualized. In practice i would like to obtain a boundig box range. How can I get it? please reply to giancarlo.amati@mail.ing.unibo.it Thank you Giancarlo Giancarlo Amati <giancarlo.amati@mail.ing.unibo.it> writes: > I would like to obtain max and min dimensions in each X,Y,Z of an > object I visualized. In practice i would like to obtain a boundig > box range. How can I get it? Use SoGetBoundingBoxAction. Morten -- <URL:http://www.coin3d.org> yes but...

What do I need to do to correct this observation: !Latex Error: Cannot determine size of graphic in XXX.eps (no BoundingBox) The graphic size is 150px. X 100px. Thanks Bernard Bernard Murphy <ber_murphy@eircom.net> wrote: > What do I need to do to correct this observation: > > !Latex Error: Cannot determine size of graphic in XXX.eps (no BoundingBox) > The graphic size is 150px. X 100px. For a quick fix you could just put a line %%BoundingBox: 0 0 <x> <y> at the beginning of your file, where <x> and <y> stand for the desired width and heigh...

A program generates 3 files, stst.dat, march1.dat and march2.dat, and I have file 0.8 lying (a vertical line). I use this script: #------------------------------ gnuplots # gnuplot << eoi set term postscript eps enh 24 set output 'march.slab.eps' set nokey set size 1, 2.1 set pointsize 2.0 set multiplot # u_0 vs delta: set size 1, 1 set origin 0, 1.05 set xrange [0:1] set yrange [0:3] set ytics 0, 1, 3 set xlabel '{/Symbol=28 d}' set ylabel '{/Italic=28 u_0}' rotate by 0 plot 'stst.dat' w l lt 1, '0.8' w l ...

Please kindly help me, I want to find the bounding box from an inverted binary image from a signature recognition, I'm confused ...

Hi everyone! I'm looking for a good explanation of minimal bounding boxes creation. I found some mathematical papers f.e. at www.magic-software.com, but they're a little bit too tough. Please, help if you know any other. regards - m z - "Michaï¿½" <firewire1@wp.pl> schrieb im Newsbeitrag news:c0algb$nkn$1@nemesis.news.tpi.pl... > Hi everyone! > > I'm looking for a good explanation of minimal bounding boxes > creation. I found some mathematical papers f.e. at > www.magic-software.com, but they're a little bit too tough. Pleas...

Is there a utility that could tell me the bounding box of a TrueType font? I need to find the biggest font size that fits in a given vertical space. The utility should check also non-Latin codepages. -Pertti ...

can anyone pls help with how to draw a bounding box for an irregular shaped image. You look for minimum enclosing rectangle in Matlab Forum for your problem. I hope you will get it. Yumnam Kirani Singh Tronglaobi Awang Leikai "meena rao" <meenaraos@yahoo.co.in> wrote in message <ies80t$ph9$1@fred.mathworks.com>... > can anyone pls help with how to draw a bounding box for an irregular shaped image. On Dec 22, 2:06=A0am, "meena rao" <meenar...@yahoo.co.in> wrote: > can anyone pls help with how to draw a bounding box for an irregular shap...

Hi, I've been looking for a fast triangle/AABB intersection algorithm that will return the bounding box of the intersecting region (if there is any). I'm aquainted with Tomas Moller's excellent code, but extracting the intersection positions didn't seem to extend naturally from it - and I wondered whether a different algorithm might be more applicable. I thought I'd ask whether anyone here had any useful pointers. Best Regards Matt You could try the routine from the book "Real Time Collision Detection" on page 169. It basically uses a separating axis test, w...

Anyone know of a way to use the results of the model size measurement (bounding box) in a relation or analysis feature? I need to have the overall size of an assembly returned as a value, preferably in the 3 axes. Thanks. I don't know if you can do it the way you say, but you can slap datum curves along the extents of the model, align them to the model extents and dimension them (the dimensions will appear as extras) then use relations to push the dimensions into parameters which you can use. This is not a robust method, there must be a more elegant way to achieve this &...

Using SW3 I have two questions for consideration. Thank you to all are kind enough to offer help. 1) Since SW is smart enough to automatically create a bounding box around a component, is there a way to access and use the size of this box for a BOM Material Size entry? Right now I am linking each xyz dim to a Special Property. 2) Can a macro be written that will link a part on sheet 2,3,etc. to the BOM Item# on sheet 1? If so, I would like to discuss $$ for someone to do it for me. This is why: I always use multiple sheets and include an informational Block with each of several items deta...

Hi, I'm looking for an algorithm that can compute the intersection between a capsule and an axis aligned bounding box (AABB). On the magic-software.com website there is an algorithm for computing the intersection between a sphere and an AABB so even if someone knows where I could find an algorithm for cylinder/AABB intersection that would be sufficient as well. Any ideas? Omair "Omair-Inam Abdul-Matin" <oiinamul@cs.uwaterloo.ca> wrote in message news:cb7str$hvd$1@rumours.uwaterloo.ca... > I'm looking for an algorithm that can compute the intersection betwee...

Hi, Assume we have two non-intersection polygons P1 = p1(x1,y1), p2(x2,y2),..., pN(xN,yN) P2 = p1(x1,y1), p2(x2,y2),..., pM(xM,yM) where "Pi" is the polygon constructed with the ordered 2D points "pi(xi,yi)", ie. vertices. They could be convex or concave. Following are two simple example polygons P1 and P2, with 4 and 6 vertices respectively. P1 : === p1(x1,y1) O----------O p2(x2,y2) \ / \ / p1(x4,y4) O-------O p3(x3,y3) P2 : === p1(x1,y1) O----------O p2(x2,y2) \...

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