# 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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### How to get plausible platformer physics with Farseer on MonoGame/XNA?

I am creating a 2D Vectorial (made of polygons, not tiles !) platformer using MonoGame and Farseer Physics Engine. Everything works perfectly, except the movement of the character which doesn't feels ...
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### Trouble With Physics Joints [Gamemaker]

I'm trying to create a series of physics-enabled 'ropes', with hard limits on how far they can swing left or right. They are comprised of an oRopeRoot kinematic physics object, which generates a ...
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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 ...
1k views

### How to implement accurate frame-rate-independent physics?

So, I have been working on a project for a while now and recently stumbled across a problem: The common approach to frame-rate independent physics is to either use a fixed update interval (ie. Unity) ...
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### Raycasting against my plane does not detect collisions in Unity

I'm trying to keep the camera above a plane which acts as the ground, so I wrote this bit of code: RaycastHit hit; if (!Physics.Raycast (transform.position, new Vector3 (0, -50, 0), out hit, 5)) { ...
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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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### UNET Performance of (many) Kinematic Rigidbodies

I am building a game in Unity in C# using the UNET networking elements. I am trying to figure out what is the performance cost of kinematic rigidbodies? My understanding is that, when kinematic, ...
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### Lunar Lander calculating gravity, acceleration and collision in GameMaker

I've already asked this on the GameMaker forums but had no response so far. I'm making a little Lunar Lander game as my first foray in to GameMaker, I'm wanting to have the ship land and take off ...
724 views

### Swinging a sword in Xcode with Sprite Kit

I'm working on making an RPG in Xcode, and I'm having a major gameplay issue when it comes to having my character swing his sword in a way that is realistic and gameplay compatible. Right now, when ...
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### Libgdx Fine Tune Megaman Movement

With help from my last question, I was able to fix the issue of having a stuttering effect if you keep hitting jump, while jumping. I believe I have managed to match moving on the X axis and the ...
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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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### XNA (BEPU) Physics Performance

Im using XNA 4.0 with the BEPU physics engine v1.2 and I have encountered some performance problems on Xbox. Im not sure if the my mesurements are an expected result of the Xbox (with alot of dynamic ...
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### My orbit code produces the wrong results

I have a GameObject called "Sun" in the sky. A game object called "GameManager" keeps track of time in the game, it is responsible for updating the hours and days. For my sun I do something like this ...
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### How do you convert angle with velocity to x velocity and y velocity?

This question can be simplified to: If you lean a pencil of a certain length at a certain angle what is the x and y position of the tip? So, basically, I am making a game that plots a balls path ...
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### How would joints work in an impulse-based physics engine?

I want to learn about physics engines, especially impulse-based ones. So I've followed along this tutorial to create some simple rigid-body physics: http://gamedevelopment.tutsplus.com/tutorials/how-...
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### How to apply physics on multiple sphere after collide like in Snooker game in unity?

I'm new in unity developement. I want to develop android game application Kanche(Marble). It's marble based game. Player need to take out other marbles from circle. What I've tried so far is, Rall a ...
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### Moving CCNode with constant speed in cocos2d

I want to move the object (CCNODE) with constant speed in any direction , what i have did till now is applied a force to object at start to get it moving and set elasticity as 1 and friction as 0 to ...
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### Handling movement on sloped surfaces - clamping character to sloped surface

I've noticed that a lot of people seem to have this issue but I've yet to find an actual working solution - when a rigidbody-based character controller (I'm not using Unity's character controller) ...
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### Trajectory Arcs

Ok so I have read this question Calculating trajectory. And it is sort of working in my program. I am trying to produce nice parabolic arcs with this. Like so .. The results I am getting look more ...
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### Unity Ragdoll Colliders don't collide

I have a humanoid character with Ragdoll setup in Unity. However the box/capsule colliders on the various parts of the body don't collide with other static geometry. They do collide with the ground ...
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### Triggers are not detecting colliders from other game objects in Unity version 5.2.2f1? [closed]

I was working on a basic slots game, and I came across a hiccup with the 2D Physics engine. Currently I'm letting the reels spin for three seconds. Once it has finished spinning, it will go to the ...
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### How to model vehicle driving physics?

How to model the physics of a car in a racing game? In real life, vehicle movement is inherited from the wheels. But after reading a few articles on the subject (a lot of which are 10 years old), I ...
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### How am I supposed to timestep this gravitational simulator

The following code is what I use to simulate a particles movement in a gravitational scenario. The problem is that this simulation needs to work well on devices with different aspect ratios, and ...
426 views

### Sprite Kit - containsPoint for SKPhysicsBody?

I have a ball bouncing around the screen. I can pick it up and drag it onto a "bucket". When my touches finish, I use the containsPoint function to check and see if I have dropped the ball onto the ...
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### 2D Change Velocity Based on Distance XY While Moving Parabolic Arc

What I'm trying to achieve is that the entity moves in a parabolic curve, and no this has nothing to do with gravity before you ask. I give the entity a target position which it should move to, but ...
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### Is it sensible to make all physics on GPU using transform feedback?

I'm learning OpenGL and today I read something new to me. It's called transform feedback, and if I understand right, it can help to get information about vertex shader variables. And I read an example ...
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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 ...
107 views

### Infinite ball bouncing problem (Unity)

I am trying to develop a basic Breakout game using this tutorial using Unity 5. But the ball starts to bouncing infinitely very easily. I cannot understand why this happenes. In my physics knowledge ...
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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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### How to move rigidbody player to its facing direction with AddForce?

How can I move a rigidbody to its facing direction? I've already tried this: rigidbody.AddForce (transform.forward * v, ForceMode.Acceleration); // v is a public float which gets a new value in ...
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### Organizing movement, collision detection, and collision resolution

There's many articles on the internet focusing on how to implement movement, collision detection, or collision resolution. What I'm wondering is how to put them together, specifically in what order to ...
257 views

### Physics: calculating angular acceleration in world vs local space

I have a pretty simple rigid body simulation written in Python. In my code I calculate the angular acceleration using formula: angAcc = torque * inertiaTensor^-1 (note row-major matrix order) Now, ...
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### Use both AddForceAtPoint and change velocity property?

I'm using Rigidbody2D for some game objects. It seems that when I AddForce() or AddForceAtPoint(), the game objects are mostly affected on the Y axis and hardly at all on the x axis. I don't ...
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### PhysiJS and objects on top of moving objects

Using Physijs which uses ammo.js. I am attempting to simply place a sphere on top of a box, the box is moving back and forth and I want the sphere to move with it while also being able to move on top ...
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### How to impale and stack targets correctly according to the collider and its coordinate?

I'm making another simple game, a catch game, where a spawning target game object must be captured using a skewer to impale it. Here how: At the start, the falling object (in red) will fall in a ...
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### How to calculate distance of travel needed get achieve speed x?

I have a boat traveling at 20 meters/second approaching destination x. Destination x has a range radius of 10 meters. What I would like to do is make sure by the time the boat arrives within 10 meters ...
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### 3D collision physics. Response when hitting wall, floor or roof

I am having problem with the most basic physic response when the player collide with static wall, floor or roof. I have a simple 3D maze, true means solid while false means air: bool bMap[100][100][...
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### Pong paddle algoritm - How to know the direction of the ball when the paddle is at bottom

I hope you can understand my question! I'll try to be very clear. Watching a pong tutorial (it was originally written in Javascript but I made the game in Python) The developer used an algorithm to ...
54 views

### Space Based Physics

How would I go about about adding space-based physics like orbital mechanics into a game engine like Unreal Engine 4 or Unity 5? The goal is to generate celestial bodies procedurally: first black ...
106 views

### Use constant force to hold something in position

This may actually be more of a Physics.SE question but since im doing this in Unity I figured I'd ask here. I am playing around with the Constant Force component and have a sphere constrained with a ...
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### How do I convert gravity from pixels per frame² into Unity's Rigidbody2D gravity scale parameter?

I'm learning Unity2D by trying to make a Mega Man clone. The first thing I'm trying to do is to replicate the original series physics. It differs from game to game, but I'm leaning towards something ...
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### Correct way to integrate scaled axis angular velocity into a quaternion

Across my travels on the internet I have came across to ways of integrating a scaled axis angular velocity into a quaternion. The first way converts the angular velocity into an axis angle quaternion ...
136 views

### Twin-stick controls for a cohesive group of agents

I'm trying to implement a classic twin-stick controller for a group of physics-based game objects. Here are the rules I'm trying to follow: Agents always stay close to each other within a certain ...
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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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### In PhaserJS, how do I get a clicked Physics.P2 body's data?

I have a sprite with Phaser.Physics.P2 enabled, using a custom shape loaded with loadPolygon() from a .json file. I have also activated its debug and debugBody properties, so I can see the custom ...
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### Calculating a smooth velocity of interaction touches

I have a touch game and it would be beneficial to be able to know the "velocity" of each touch on the screen. Let me explain. Right now I am already subtracting current touch position from previous ...
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### How to resolve multiple simultaneous ball collisions in a pool game?

I'm trying to simulate a break shot in billiards (1 ball hits a pyramid of 15 balls). The formula for 2D ball collision works correctly in my game. But when it is applied to the break-shot, the result ...
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### Unity 2D Torque at position [duplicate]

I'm working on a 2D space game in Unity, and I wanted to include ships that might have reaction wheels centered around places other than the center of mass. If so, I'll need to be able to apply torque ...