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-1
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0answers
17 views

Collision detection for two moving objects

There are 2 objects $A$ and $B$. Both have 2 sensors. The sensors can measure a distance to another sensor. Let's say the sensors are $AF$ (front sensor for $A$), $AR$ (rear sensor for $A$), $BF$, ...
1
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0answers
62 views

How can I use the Bullet-Physics's ray-cast normal to calculate angles for a object to lay on a surface?

[Give the normal of a surface in XYZ format, how do I calculate rotations (also in XYZ format) needed to set an object parallel to the surface?] I have a collision library that uses the bullet ...
0
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1answer
31 views

Sphere intersecting a triangle

I'm studying "game physics" programming, and in this article, at page 14, I don't understand how is the author right. ... if the sphere does indeed collide with the inside of the triangle then a ...
0
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0answers
33 views

Shared Volume of Overlapping 3D Cubes/Rectangles

Good afternoon, I have been looking for an approach to figure out the volume where two cubes/rectangles overlap, meaning, I know when they do, I just don't know the coordinates of the volume in which ...
0
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2answers
90 views

Algorithm to find a line segment is passing through a circle or not?

I have a line segment between two points P1 (X1,Y1) and P2 (X2,Y2). And I have a circle at point Q(Xq , Yq) with radius R . Can I have an equation in which I can put these values and the result shows ...
0
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1answer
52 views

What is the optimal way to detect a collision between an AABB figure and a non-AABB figure?

Background I'm looking to do this programmatically in Java, but if desired you can post solutions in C/C++ or plain English instructions if you're not a programmer, but I would appreciate an ...
0
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1answer
166 views

How to calculate solid angle of a rectangular detector of 20cm x 10cm?

I have an detector of $20cm*10cm$, how can i calculate the solid angle subtended by the detector if the detector is placed at $30$cm apart? Because directly i cannot use the formula ...
4
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2answers
277 views

How do I find the Intersection of two 3D triangles?

I've got a rather complicated geometry problem that I'm trying to solve - how to find the intersection between two triangles in 3D space. I've looked around at other questions and answers on this site ...
2
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0answers
49 views

Hashing Probability

I have just started to learn about the topic of hashing. I understand how it works and the difference between closed address and open address, but do not know how to calculate the probability of a ...
0
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1answer
37 views

Calculate intercept location and time

I want to calculate the coordinates and time where object B2 can intercept object B1. Asuming the following: All coordinates are in pixels B1: Moves from coordinates A1 to A2, it has a speed of 2 ...
0
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0answers
13 views

n people and n saved seats - basic probability question [duplicate]

There are n people, each has a ticket for specific seat among the n seats in the theater. First person loses his ticket, and seats in a random seat. From now on each person 2,...,n tries to seat in ...
0
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0answers
22 views

Size of AABB penetration

If I have two 3d boxes represented as aabbs, and their centers and halfwidths are represented by vector 3s,and I know they've penetrated each other. Would subtracting their centers from each other and ...
0
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1answer
37 views

How do you determine if two triangles are intersecting for collision detection?

I've been scouring the internet for things about intersecting triangles. I haven't been able to find something that just gives me the math and what all the variables are equal to. I would love the ...
0
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0answers
7 views

Max and Minimum movement overtime span.

I need some help calculating the maximum and minimum movement of an object over a time span. For the Max movement I have a Vector in space, a start time, and end time. I'm looking for the maximum ...
0
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0answers
30 views

Finding a plane where a vector lies (and generating its normal)

I have a vector in homogeneous coordinates $l = (a,b,1)$ and want to calculate a plane from it (for later doing intersections in 3D coordinates and calculate collision coordinates) with regards to the ...
3
votes
1answer
35 views

Simulating elastic collision

I wrote a simple program where i can move around some objects. Every object has a bounding box and I use hooke's law to apply forces to the colliding objects. On every tick, I calculate the forces, ...
0
votes
1answer
45 views

How to find initial direction and angle of collision of a ball with a vertical wall?

I have a problem in my game. I have a wall where a ball hit to a wall from anywhere. I need to give it to the direction according to the collision law. Let suppose if a ball thrown from $(0, 0)$ and ...
0
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0answers
112 views

How do I detect if two polygons overlap each other or not?

I'm developing a game engine. Currently I'm writing the collision detection part. I have to write down an algorithm which detects if two given polygons are overlapping each other or they are separated ...
0
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0answers
92 views

Tomas Moller's Triangle-Triangle Intersection

I'm reading Tomas Moller's "A Fast Triangle-Triangle Intersection Test" (http://web.stanford.edu/class/cs277/resources/papers/Moller1997b.pdf) and am at a point where I'm not sure what he is talking ...
0
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1answer
61 views

Find the plane a triangle lies on

I am trying to determine if the plane on which two triangles lie intersects for a collision-detection implementation. Unfortunately, I'm stuck at step one, which is finding the plane on which a ...
0
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1answer
53 views

Collision Detection in Finite but Limitless Space

Doing collision detection on two arbitrary rectangles is easy, given their coordinates and dimensions. In regular 2d-space, that is. But what about "finite but limitless" space, say a screen area ...
2
votes
2answers
100 views

Probability of 8 or 9 digit sequence colliding in the same place in two 65 digit numbers

I have two numbers: 3032643431333337636238613038343231383364303731376566303037663231 3861663464383131656131653461343961343364303737663565356561653361 36430373 ...
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0answers
41 views

$C^{\infty}$ distance function for polygons?

I'm exploring some novel/weird ways of doing continuous collision detection. Suppose I have two (possibly concave) polygons in $\mathbb{R}^2$ and I want to find the "distance" between them at a ...
1
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1answer
26 views

Assuming a ray defined by a starting point and a direction. How can I tell if a plane is behind it or in front of it?

If I have a ray defined by a starting point and a direction, and a plane defined by its normal and its distance from the origin, how can I tell if the plane is in front versus behind the ray? By ...
1
vote
4answers
371 views

How to find the intersection point of two moving circles?

I'm trying to develop a simulation in C#, and I have to find the intersection (or collision) point of two moving circles, in 2D space. Actually one of my circles will be stationary, so only one of ...
0
votes
1answer
28 views

Optimized collision check for all pairs using bounding volume hierarchy

I am working on broad-phase collision detection. I understood how to build a bounding volume hierarchy using AABB's as bounding volumes. I also understood how to check all collisions of a single AABB ...
1
vote
1answer
60 views

Repeated Random Number Selection Until No Collisions - Number of Repetitions

I have a problem that has to do with my research that troubles me for a while and I could not find a solution either by myself or online. Suppose you have $n$ people in one room. Everyone picks a ...
0
votes
2answers
113 views

Collision detection between two accelerating spheres with no initial velocity?

We have two non-touching spheres of radii r1 & r2 are lying in space at rest. Both of them are then given accelerations a1 & a2 respectively at time t=0. Find whether they will ever come in ...
4
votes
2answers
333 views

What's the shortest distance between two cubic Bézier curves?

This question comes from TeX.SX http://tex.stackexchange.com/questions/183123/whats-the-minimum-distance-between-two-bezier-curves (From typography; TeX) We are trying to find minimum distance ...
0
votes
1answer
114 views

N points in a circle around a point on a sphere.

Consider a 3D sphere: $(x_{c}, y_{c}, z_{c})$ : cartesian coordinates of the center $r$ : the radius Consider a random point on the surface of this sphere of coordinates : $(x_{0}, y_{0}, ...
1
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0answers
654 views

2D elastic collision using Matlab

I recently started using Matlab and am modeling hard spheres in 2D. I have n particles, their positions are given by two arrays x(n,1) and y(n,1). The simulation has N time steps. I set up a distance ...
0
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0answers
54 views

Collision of two moving lines (3D)

I have two lines / edges moving with linear velocity in timesteps. How do I determine whether the lines collide / intersect in the intervening period? My lines are (P1,Q1) and (P2,Q2). The endpoints ...
0
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1answer
113 views

Find all the intersection points of a vector parabola (in R3) and a sphere

Given that I have a vector in R3 (7t, 10t - 2t^2, 5t) | (These numbers are arbitrary for the sake of the process) A sphere centered at the point ( 15, 25, 10) with a radius of 20 There is a ...
0
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1answer
118 views

Resolve A Circle to Rectangle Collision

In 2D, I have a circle and a rectangle, the circle has properties: density: 0.7, velx: 2, vely: 3, rad: 20, centx: 20, centy: 10 and the rectangle has properties: topx: 200, topy: 300, width: 500, ...
2
votes
2answers
51 views

Moving segments colliding

I need to check if the edges of two triangles will collide. I do an edge-edge check for each pair. One segment is stationary, while the other moves with constant velocity. The segments are not ...
0
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3answers
54 views

Crash and Collision - Kinematics Question?

Vancouver is 300 km away from Seattle. Two friends, one leaving from each city on a bike want to find a campsite between the two cities. One cyclist starts from vancouver at 25 km/h. His friend will ...
0
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1answer
55 views

Closest point out of collision

I am tackling IMO very hard problem from geometry "How to find closest point out of collision". To explain it better I've drawn an image explaining it. Basically: given a point on 2D plane( yellow ...
0
votes
1answer
41 views

How to compute characteristic polynominal of two conics

If I have two conics defined as $A: XAX^T$ and $B: XBX^T$ how can I expand characteristic polynomial $f(\lambda) = det(\lambda A + B) $ so that it can be computed by a computer program or Matlab?
1
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1answer
77 views

Avoiding collision with a plane

I am developing the software to control a common fly's flight in Opensim simulator, although I am facing some troubles determining when the fly must maneuver to avoid hitting a wall. Questions How ...
0
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1answer
1k views

Sphere-Sphere intersection c#, 3D coordinates of collision points

Ive had a look over numerous 3D sphere-sphere intersection questions and unfortunately they are either too far ahead of my ability to comprehend or not tailored to what I am looking for. This is ...
1
vote
1answer
292 views

Finding coordinates of a path

I am trying to find out whether to geometrical shapes overlap. This is based on an SVG-file. The following is an example: Group 1: ...
0
votes
1answer
343 views

Determine angle of incidence/reflection off of slanted line?

I'm working on an air hockey game (for learning purposes) and I'm currently struggling with some geometry. I'm trying to determine the new slope of the velocity of the puck when it collides with one ...
3
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0answers
144 views

Finding collision for a hash function

Is there a way to find a collision for a given hash function without brute forcing? The particular hash function I'm talking about is the one used by Python (simplified version given below). It ...
2
votes
2answers
2k views

Detecting an Intersection between Simple Shapes

I have a circle, ellipse, square or a rectangle, and I want to determine if it intersects a given triangle. I am looking for the easiest way to determine if there exists a geometrical intersection ...
0
votes
1answer
77 views

simple rectangle collision

I have 2 rectangles (black and blue), each of which are defined by 4 floating points values based on their location (left, top, right, bottom). For example, a 25 x 25 rectangle might be defined as: ...
0
votes
1answer
255 views

Collision detection of two circular sectors in mixed polar and Cartesian coordinate

I am trying to solve the following collision detection problem. Suppose we have two circular sectors, each described in their own polar coordinate system with four values $r_1$, $r_2$, $d_1$ and ...
0
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1answer
172 views

How to find the point of collision between an irregular shape (built out of 3 circles) and a line

I'm making a program in which many weird shapes are drawn onto a canvas. Right now i'm trying to implement the last, and possebly hardest, one. In this particular shape i need a way to find the ...
1
vote
1answer
117 views

What's the minimum number of points I need to measure to find out how much two rectangles are overlapping?

This is for a web app, but I think it's a general geometric problem, and almost certainly a solved one: I have a rectangle $(A)$ and I know its size. I'm trying to figure out if there's another ...
2
votes
2answers
395 views

Ways to define a curve

I'm trying to give shapes in my physics engine roundness/ curvature. I am aware of various methods for mathematically defining curvature such as bezier-curves, ellipses, etc; but I'm not sure which ...
1
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2answers
2k views

Angle of reflection off of a circle?

I've made simple 2D games in the past using mostly just squares. If an object collided with another object (all squares/rectangles) it would just change the slope to the opposite based on what side ...