# 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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### Issue translating objects by one unit in the y direction

I'm currently making space invaders (in OpenGL/SDL) and I'm running into an issue with the movement of the aliens. I have a 2-d vector of aliens (5 rows of 11) and I'm translating each in the x ...
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### Unity rigidbody exhibits a premature max speed

In effort to build a racing simulator, I have been working on a working model for the pistons in the engine, and have come to a bit of a stand still. I have gone through extensive testing, through ...
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### Farseer 3.5 RevoluteJoint Breaking

I think I'm missing something completely and the solution is unbelievably simple, but I'm at a loss at the moment. I'm trying to build a stylized car, with a rectangle as car body with two circles as ...
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### Rigidbody2D Circular Orbiting

I am trying to create a basic solar system in 2D. All space objects has CircleCollider2D on them (which are required for raycasting in another script). Currently planets are childs of stars, and ...
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### How to resolve push block physics in a 2D side scroller puzzle

I've been working on a 2D tile-based side scroller puzzle game in Unity with obstacles such as doors, keys, fans, portals, etc., but one type of obstacle, push blocks, is giving me some issues. Here ...
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### How to calculate/detect the force of a collision? (Game-Maker Studio)

How can I use game-maker to detect the force in a collision between two mobile (not fixed) objects? This is used for damage calculation and possibly compression calculation. My problem is this: ...
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### Lateral Slip of car

I have been following this Gaming Institute tutorial and tried to make that car physics system in Blender Game Engine. https://www.youtube.com/watch?v=EdjUS85yVuI&list=...
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### HingeJoint shaking, Unity3D 5

I have player with CharacterController and door with HingeJoint, I also have enemies with NavMeshAgent. When someone gets inside this door, it starts shake, jitter, rotating etc. For player I use this ...
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### How to calculate acceleration and deceleration

I have a car with speed x, and can accelerate at a rate of 0.5 m/s^2, and can decelerate at a rate of -0.1 m/s^2. Maximum speed is 20 m/s. To accelerate the car speed, at each frame I need to do: ...
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### When are Lagrangian Mechanics useful in a game?

I have not used or heavily studied Lagrangian Mechanics before and I have not built a physics engine modeled with constraints yet. I understand that Lagrangian Mechanics are an alternative way to ...
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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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### How can I handle multiple force in Unity?

I'm trying to get my character to perform a "dash" where their x velocity increases rapidly and then falls over time. However, I'm also maintaining a constant x velocity so the character appears to be ...
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### Keep gravity velocity the same all the time

I have 2D rigidbodies that fall to the ground, however they speed up while falling. Also, when they freeze in the air and then unfreeze, the velocity is set to 0 and they gradually start speeding up ...
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### How do I simulate vehicle movement in a non-gravity environment (e.g., space)?

As a series of small experiments, I've began to tinker with game development, specifically using SpriteKit and Swift. I'm looking to simulate a body moving through a non-gravity environment, ...
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### Player keeps bumping when walking over to another sprite

So, my problem is that my play when he walks over to another sprite he will stop. I fixed that by adding a physics material with 0 density and 0 friction to the player and adding a circle collider ...
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### 2D sunrise in Unity

I see a lot of guides on how to create sunrise in 3D space, but I can't find much information on how to do it in 2D. In 3D, you rotate a lightsource around itself, but in 2D, I need to move the object ...
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### Issue with detecting collisions in Pong

I've been working on making Pong in OpenGL and SDL and currently have both paddles and the game ball set up properly. I have an Object (or Entity) class which is used to instantiate each of the ...
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### UE4 - Physics Body Character Movement

'Ello folks! I'm looking for some advice on how to implement a certain system in UE4 - I've been trying to develop this system for a few weeks but it's been a buggy and largely ineffective attempt. ...
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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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### What Is Vector Math? [duplicate]

Okay so I was wondering, what exactly is "Vector Math"? I was wondering if I needed to know physics for game development, and most people said you just need to understand the basics, but they said ...
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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 ...
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### How often should I calculate the position of a bullet?

In game's like Battlefield or Arma, how many times per second is the position of a bullet calculated?
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### Should a transform class store a matrix or seperate position/rotation/scale values?

I'm creating a transform class to make storing the transform of individual objects in a scene easier, but I'm unsure on how to do it. I could create one like this: class Transform { public: //......
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### Should the bullet trajectory calculated by server or by client? [duplicate]

In a FPS game like Battlefield or Arma, when playing online, should the bullet trajectory be calculated by the server or by the client?
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### AS3/Flash Develop - Radial Gravity (character on planet simulation)

I am trying to create a program where a character shape will be constantly drawn towards the centre of a planet shape. I have taken on previous advice into using physics equations to generate the ...
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### Implementing time step in main game loop

So ive read both http://gameprogrammingpatterns.com/game-loop.html and http://gafferongames.com/game-physics/fix-your-timestep/ and I kind of understand how I'm supposed to do it, but some parts are ...
405 views

### Simulation of supersonic, hypersonic flight with user defined surfaces

I want to create a small rocket-launching game, inspired by Kerbal Space Program. Since there's nothing in orbital mechanics, that I still don't know. I decided to make this as close to reality as ...
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### Unity3D - Using AddRelativeForce to push an object forever in zero gravity environment

Ok, I use AddRelativeForce to basically push an object. But it suppose to keep flying and keep accelerating as I hold down the key because I didn't set gravity. I just started Unity3D last month, so ...
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### Multiple Colliders in Collision

I have an object that has a front collider, left collider and right collider. When a collision occurs, I notice that there are situations where the front collider and left collider/right collider has ...
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### Can I make this physics simulation any faster?

I've made a little real time physics simulation that solves some bodies. CirclevCircle && CirclevOrientedRect I would like someone to tell me if I'm doing something drastically wrong. I know ...
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### Rigidbody stuck on the edge of two colliders

could You please help me with that weird bug? I've seen other people's posts about that bug, but I couldn't really understand how to fix it. As You can see, the boxes are standing right next to each ...
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### How to apply force to rigid bodys at a specific point?

I am trying to write a physics engine from scratch to get a better understanding of them. It worked pretty good so far, but there is one thing, i can't get my head around: If i have a rigid body ( ...
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### How to implement jump in a 2d game?

I am trying to implement jump in a game I have written for android using canvas. I have referred this tutorial for implementing jump. My code is like if(jumpKeyPressed){ jumpVel = -...
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### How to get dynamic RigidBody rotation/tilt on uneven platform?

I have a rigid body with PolygonCollider2D which has some complex circular shape and I'm using uneven platform. Im using Following code to move the object forward CharacterRigidBody.velocity = new ...
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### How to make rigid body move smoothly on uneven platform?

Right now I'm using Rigidbody2d for the game character along with polygon collider 2D(2d platform game). I'm beginner hope I'm using correct components. And transform to move character from left ...
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### How to disable Camera from tilting when following a game object?

I have a game character object which is followed by camera. Camera is child object of Character. Using rigid body makes the character tilt in slopes and camera tilts too. how do i stop camera ...
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### Restricting Maximum Velocity in Space

I'm making a top-down 2D space ship game in which you rotate and thrust. I'd like to impose a maximum velocity for different engine types, meaning that a certain engine can only get you going up to a ...
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### Bullet Physics: Difference between Motion State and World Transform

In Bullet Physics, when I create a new btRigidBody, one of the parameters passed to the constructor is the btMotionState, which defines the initial pose of the body. However, if I then later want to ...
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### Synchronizing players and game objects in a server/client multiplyer game

OK guys, I have some experience with 2D game development (single player only), so that's fine no questions here. The problem is with multiplayer games. I already read lots of other questions and ...
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### How to apply friction vector to acceleration in top-down 2D game?

I'm making a top-down view 2D RPG game, meaning the player can move in any direction on a 2D plane, and I'm trying to implement a somewhat realistic non-orthogonal acceleration/friction physics model ...
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### Dealing with collisions across adjacent static bodies

The Problem: I have the following setup: A, B and C are rectangular static bodies in box2d. p is a circular dynamic body in box2d. The movement of 'p' is solely controlled by the current gravity ...
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### In a 2D physics engine, how do I avoid useless collision resolutions when objects come to a rest?

In a physics engine I'm developing (for learning) using love-2d, I implemented collision resolutions in this way: FixedUpdate(dt) // I use fixed timestep foreach collide c1 in allNotStaticColliders ...
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### why doesn't work this example [closed]

I am new to game development. I was trying to use this http://blog.gemserk.com/2012/07/03/drawing-a-projectile-trajectory-like-angry-birds-using-libgdx/ projectile example in eclipse android using ...
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### How do I set angular velocity/torque so that it's pointing to velocity/direction?

Right now, when I spawn a shootable object, it goes like this: Because I just set it's angle to this: float aimAngle = (float) Math.atan2(velocity.y, velocity.x); bullet.setBodyAngle(aimAngle); ...
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### Ball Speed is not increasing as per code

I am working on small project , but now I have a problem . The problem is The Player speed (Ball speed) is not increasing as per the code . In the beginning ball speed increases , but as the time ...
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### How to stop sinking bodies in physics engine C++

I'm writing a rigid body simulation in C++, and have come across a problem when an object should come to rest on the ground. Because gravity is being applied to it's velocity, the object starts ...
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### Calculating initial velocities given trajectory parabola

I'm working on a volleyball game but my maths/physics knowledge isn't quite up to par. I need some help with the following problem: The player can hit the ball from anywhere on the left of the court ...
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### How to find or compute or look for overall/max RPM by simply checking for rotation?

I find it hard to determine the wheel RPM since I'm only making a simple 2D game of rotating object via Z-axis. I wanna try this solution but I got no change since I'm trying to find the RPM from a ...