# Tagged Questions

Relating to the motion of objects through space and time. Including concepts such as acceleration (thrust and gravity), mass, collision response, friction and more.

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### Game Physics with RK4 and VB.NET

http://gafferongames.com/game-physics/integration-basics/ I tried to have a go at porting this to VB.NET: Public Structure State Dim x As Single ' position Dim v As Single ' velocity End ...
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### Gravity wells that go with finger [duplicate]

I have a simple particle game, where all the particles are arranged in a grid. This game is for touch devices so to take advantage of it I am trying to have a multitouch gravity field thing going on. ...
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### How to make an object fly disabling gravity through C# script in unity

I want to make an object fly which has ridged body physics by disabling its gravity after pressing a key. So I just want to know how to disable gravity through C# script. I already went through google ...
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### Bouncing Balls in angular movement

I'm trying to bounce a ball off of a wall based on angular movement. The ball comes in at angle X ( lets say 30 ). Bouncing off with the equation 360-ballangle works for the left and right walls 180-...
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### 2D circle against a corner change in direction

I have a 2D Ball that might go against a wall. If the Ball goes against the wall perpendicularly, it will just invert its direction (assuming no air resistance and no bounces that should make its ...
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### How to move 2D objects based on mouse movement with pointer locking?

I'm using pointer locking for a 2D game (where you perform calculations based on the delta in mouse positions from frame to frame). I'm having some basic math/logic issues with accomplishing what I ...
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### Creating 3D gravity in zero-G tied to mass in unity with c#

As a total beginner, I've been working on a patch-job script for a gravity mechanic in an open space sim, I want to derive all my objects from this "Block ALPHA" object and its' set of variable ...
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### Simulating elastic ball collisions quickly escalates to disaster

I'm trying to learn HTML canvas and was working on a basic physical simulation, where a number of balls are drawn and set in motion, and the program simulates them colliding and bouncing off the walls ...
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### Game Physics: Calculating a collision response using the Separating Axis Theorem?

I am working on a project in which I have implemented the Separating Axis Theorem to detect collisions between objects. My current collision response is an object that contains whether it is ...
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### In Unity3D (and PhysX), how do I calculate the products of inertia?

Since unity3d uses physx underneath the surface, obviously they share the same features. One of the features is the moment of inertia tensor - Unity3D one, PhysX one. Though, they use the diagonal ...
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### Implementing proportional navigation in 3D

Good afternoon guys, a = N * λ' * V is the formula for the commanded acceleration required to hit the target, where N is the proportionality constant, λ' is the change in line of sight and V is ...
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### Calculating the angular momentum of rigidbody in Unity3D

Knowing that angular momentum in 3D is L = Iω (moment of inertia times angular velocity), how do I calculate it in video game world? In unity3d I have the diagonal inertia tensor rigidbody....
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### In Unity3D, what is the relation between inertiaTensor and inertiaTensorRotation?

In unity3d there are two properties on rigidbody that correspond to the moment of inertia tensor. One of them is: rigidbody.inertiaTensor, which I know is the diagonal of the inertia tensor, The ...
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### Algorithm to propagate internal Physics force in a structure of building

Scenario: A floating structure composes of many nodes (or in more visual meaning - a cubic block). Every node is snapped to the same 3D grid. (similar to a minecraft castle) There are external ...
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### How to program friction in an air hockey game in Cocos2d-x 3.11?

I'm developing a simple air hockey game, and I have a question about friction of puck and puddles with the game scene. How can I do that? I'm using cocos2d-x default physics engine, and the friction ...
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### How i can make better jump to my game? - C++ SFML

So, I ask question about my 2D game, actually it is not game, but it is something like poor game. Well i made moving system and now is time to make jump. I made some kind of gravity with tutorial but ...
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### Box2D + SDL - Weird body positions

I'm having a problem where either my sprite, or my body position is off. Here's a picture so you can see exactly what's going on : (The box has stopped on the picture, probably because it's colliding ...
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### Centripetal Force

I'm using C++. So, I found this post on here that gave me a good start. I have managed to correctly add centripetal motion to my enemy objects. Since the objects are constantly changing direction, ...
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### Hinge/Configurable Joint rotating even if constrained

I already posted the question over on Unity forums, though, I have to say, this place often seems more professional and knowledgable, so here goes mirror post. I have a Cylinder with a Hinge and a ...
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### add physics to a group or container body in phaser

I'm developing a HTML5 Phaser game. In this game I do have a Group which I would like to behavior as a physics body (arcade-physics). It is a character with a lot of moving parts (sprites) inside ...
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### Obtain jump vector given time, distance and gravity

I tried for several days to solve my problem , but in the end I just gave up and I decided to ask , since the solution is beyond my knowledge I'm writing a 2d top-down game, in order to simulate the ...
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### Turn Radii and speed calculations

Ok guys I'm an aspiring game designer and I'm trying to develop a racing board game using real life as a basis for my mechanics. The problem im having is I'm not very mathematically inclined I found ...
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### Why is my 2D rigidbody behaving strangely with a negative scale?

I've been making a system that when you click on a monster's limb it destroys the limb you clicked and makes fall to the ground the children limbs. There is a rigidbody attached to the monster ...
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### Everything is set to Bounciness 0 - Why am I still bouncing?

I am creating a platformer where rather than manipulating the character to get them from the beginning of the level to the end, you manipulate the world. Thus, when you want to make the character '...
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### Problems with voxel physics

So I have a problem that is divided into performance and how to solve it in voxel physical, obs: I'm using Cubiquity. What am I doing: I test all the blocks. When a different block and air is greater ...
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### Constant orbit using Rigidbody in Unity

I'm trying to make a few game objects (moons) orbit a planet in unity. Basically just picture a planet in the center of the screen, and a few small moons that orbit the planet with a constant velocity....
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### Collision detection with Physics P2 in Phaser.io

had written this thread that relates to a project I'm developing while trying to learn phaser. I could really use some advise/ feedback on making the user experience a bit more easier as I seem to be ...
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### Unreal Engine Physics creation is slower in Editor

I just figured out that when UPrimitiveComponent::CreatePhysicsState() is called, it calculates the mass, but only in editor, also when i build for non-editor it is faster (standalone) this is not ...
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### Dropping through a platform in Clickteam Fusion 2.5

I am using Clickteam Multimedia Fusion 2.5. Currently, I have a rudimentary platformer game, with the following setup: player object is set as a physics platform, with the physics engine added to ...
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### Make Kinematic P2 Body collide with world bounds

I have a P2 object( A) with a custom bound that detects collision with another P2 object(B ). However, object A is set to be kinematic rather than dynamic as I do not want object A to react to ...
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### AS3/Flashdevelop - Controlling a 2D character to move around a planet with gravity

With a little help I have managed to create a 2D planet with working gravity that constantly pulls a character towards its center. The only problem now is that I am completely stumped on how to make ...
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### Collider not working

I have a 2D object (without a parent) with a 2d box collider (dimensions are not small) added to it and set as trigger when I place it in the scene it works just fine however when I instantiate its ...
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### Move ball through a direction angle in android canvas [duplicate]

I am building a simple game in android. I am successful in first step where I draw a ball in canvas in touch point. Now I am trying to move it from an initial point A (center) through the touch point ...
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### Phaser P2 RevoluteConstraint motor not working

The following code produces a flipper and four balls that seem to interact as they should. They all collide with each other and the game world bounds. The problem is that the motor isn't working, nor ...
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### Limit rotation of flipper joint?

I have a working RevoluteConstraint using Phaser.P2.Body, and the motor enabled with the speed of 1, the flipper appears as it should, but only rotates around slowly. I'd like to set the normal ...
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### Stopping 3D object in place

I am at 1.2 stage (moving the player) at Unity course "Roll-a-ball" and have question: I want to add feature that stops a player and sets his new position on 0, 0, 0. I can reset the position, but I ...
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### Simple 2.5D flight movement

I'm building a simple 2.5D Dogfighting game, kinda similar like this one: https://gfycat.com/PleasantDeterminedArcherfish for the moment my movement works like this: if (Input.GetKey("left")) ...
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### need to make a ball travel in the angle it was hit from

self.hitBall = function (ball, x, y){ var angle = Math.atan2((x - ball.centerX), (y - ball.centerY)); ball.velocityY = (Math.sin(angle) * 10); ball.velocityX = (Math.cos(angle)...
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### Bounce with multiple collisions

Here's the problem: I'm writing arkanoid-like game in Unity 5.3. I'm using 3d physics and simply ignoring z-axis in computations. No gravity, 0 drag and velocity reset every bounce by script. My ball ...
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### Rigidbody2d and square steps

Well, I am developing small game based on Rigidbody2D character. He should go horizontally, jump and automatically climb on rectangular stairs when walking on them. I know slopes is a possible ...
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### Accelerated movement in a specific time to a specific point

I am trying to move my sprite in a specific time to a specific position while using frame-independent or time-dependent movement. My sprite is also accelerated every frame to simulate gravity. I know ...
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### 3D Physics in Marmalade SDK

I am trying to make an 3d game in Marmalade. I am completely new to Marmalade. How to add 3d physics, gravity, dynamic object, sensors, colliders in Marmalade. I was going through the API and did ...
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### Detecting collision between 2 convex meshes in 3D

For the past couple of weeks I've been trying to implement physics in my engine, and I am currently stuck on the collision detection phase. In short, I can perform a triangle-triangle intersection ...
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### How do I stop the player from rotating when they collide with a tile?

I use Touch movement and if I jump and hit a corner with the feet of my player, my player rotates but I don't want this. Can anyone help me jumping without rotating if I hit anything ? here is my ...
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### Phaser - Tween scale with physics (push other sprites)

I have an immovable sprite. I'm scaling this sprite up with tween but I don't know how to make it push other sprites (with physics) on it's way. Any help would be appreciated. See the gif to better ...
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### How to replicate Unity's Rigidbody.AddForceAtPosition in C++?

I am trying to replicate the function Rigidbody.AddForceAtPosition of Unity in C++, it means, to apply force to a body offset from its center. How could I achieve that in C++?
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### Oscillating an object left and right based on it's current orientation

I'm currently implementing a fire animation in HTML5 Canvas using the phone's accelerometer. Regardless of the phones orientation, the triangles for the fire move upward. So you can spin your phone ...
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### BulletPhysics ship rotation

First of all, I'm a beginner in game physics, and I think this is a relatively easy problem that I'm not grasping. Short Version: I have a box(representing a ship on water) going forward with a ...