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$C^{\infty}$ 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 ...
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1answer
20 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 ...
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4answers
136 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 ...
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1answer
13 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 ...
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1answer
41 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 ...
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2answers
69 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 ...
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2answers
80 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 ...
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1answer
49 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}, ...
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0answers
186 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 ...
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0answers
22 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 ...
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1answer
59 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 ...
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20 views

Line VS Circle Collision

Circle: cx, cy, r Line: x1, y1, x2, y2 What is the equation to see if they collide? (2D) I need an equation with it's final end returning true or false, since this is originally a problem for my ...
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1answer
54 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, ...
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2answers
37 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 ...
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3answers
38 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 ...
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1answer
46 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 ...
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0answers
21 views

Separating Axis Theorem - curved lines

I'm trying to work out a collision detection algorithm using SAT. I get how to test for collision between two polygons, and between two circles, and also between a polygon and a circle. But I don't ...
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1answer
38 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?
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1answer
68 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 ...
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1answer
496 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 ...
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0answers
127 views

How to determine the point of intersection between two points and a vector as seen from a “plane-line” perspective?

I have two points which I call Point(X,Y,Z) and PlaneCenter(X,Y,Z), and a vector called ...
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1answer
124 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: ...
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1answer
207 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 ...
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0answers
76 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 ...
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2answers
1k 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 ...
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1answer
71 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: ...
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1answer
199 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 ...
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1answer
142 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 ...
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0answers
206 views

Finding the point of impact between two object with constant velocity, where only angle is variable

Given two objects, A and B, with the following parameters: $A_\mathrm{angle} = 30^\circ$ $A_\mathrm{velocity} = 10\ \frac{\mathrm m}{\mathrm s}$ $A_\mathrm{Timealive} = INF$ $B_\mathrm{velocity} ...
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1answer
96 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 ...
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2answers
372 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 ...
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2answers
1k 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 ...
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2answers
123 views

How to calculate the resulting velocitys and rotation speed after two concave polygons collide in 2d

so I've been searching google for how to do this, but all anyone seems to care about is collision detection =p, and no results come close to teaching me how to calculate 2d elastic collision between ...
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2answers
1k views

2D elastic collision equation: How does it work?

Hey so I recently started learning physics, and came upon this wonderful site that taught me how to calculate 2D collisions between two circles. The only part I'm confused about is how the velocity ...
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0answers
42 views

What are the techniques one can used for rule based plane generation?

I've asked the question here at gamedev SE, but the response wasn't too encouraging. So I try to reask again, from a slightly difference perspective. I have a terrain, which is defined by mesh. And ...