# 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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### calculating avoidance forces for similar objects unity [duplicate]

I am trying to work on collision avoidance for my troops. Currently all my troops have their target object as the leader who is wandering in physical space. The troops just follow the leader but they ...
65 views

### Moving object towards a target Unity

I am trying to implement a script where basically my players would reach the target destination. Below is my script private void MoveTowardsGoal(){ if (Vector3.Distance ...
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### Wandering motion in Unity

I am trying to come up with a smooth wandering motion for my game-object using Unity. What I currently doing is rotate the object by some random angle calculated every 1.5 second delay. But I am ...
205 views

### 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 ...
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### Collider2D and Rigidbody2D, how do they work?

I have been learning JavaScript and Unity for a week now. I learned how to make Cube as a Ground and another Cube as a player and I used this code to make the Player Cube move forward and backward and ...
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### How can I simulate a magnet that attracts a ball in a 2D enviroment?

I am making a top-down game where you have to move a ball from point A to point B. You are attracting the ball using magnets that are standing still. The ball needs to get pulled by multiple magnets. ...
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### Grid collision - finding the location of an entity in each box

I am trying to implement grid-based collision in a 2d game with moving circles. The canvas is 400x400 pixels. Below you can see the code for my Grid class. What I want it to do is check inside which ...
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### What is the easiest way to make an object follow the edge of a sprite?

I have a rounded rectangle sprite and another sprite that's just a circle. I want the center of the circle to follow the edge of the rounded rectangle. Is there any easy way to accomplish this task? ...
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### Calculate an approximate distance between two rigid bodies or OOB

Is there any easy way to get an approximate distance between two OOB? I searched around and people talk about GJK algorithm, however I don't see it returning the distance between two convex objects ...
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### How to apply physics when you have sub frame state changes?

I'm currently calculating my physics every 1/100th of a second and using a state machine to manage the current state of the player. In my main loop I'm checking user input and transitioning the state ...
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### Unity Physics Material - Character Slides Too Much

I am currently working on a 2D platformer in Unity. I am using a prefab from the AssetStore for my character (The last paragraph contains a link to the prefab). The character has a circle collider for ...
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### GGX specular BRDF is way over 1!

Now, the classic Torrance derivation for roughened surfaces which Cook took into vectorized form yields the familiar parametrization of a specular BRDF where we have the NDF which decides how much ...
104 views

### Spritekit - gradually apply force vector in different direction (space ship turning)

I have a space ship that I'm applying a force vector to using a joystick for control. I would like this to smoothly fly around when I'm switching directions.. Exactly like minisquadron if you've ...
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### Bullet 3D Physics Objects Not Rotating?

So I've got Bullet 3D controlling the motion of objects rendered with DirectX. In the clipping below I've got 2 identical rectangles & 5 balls. The lowest rectangle has a mass of 0 and doesn't ...
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### Implementing a motorized hinge joint

I have a 2d physics engine, with three boxes: "body", "left wing" and "right wing". The wing boxes are connected to the body using a hinge joint. The physics world has no gravity. I'm attempting to ...
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### Unity, Unrealistic Sphere On Inclined Plane

So I am trying to model a ball rolling down an inclined surface in Unity based on what I am observing in real life but it is still quite off. In Unity it takes the ball about 3 seconds to travel ...
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### Drawing a object with Box2D and HTML5 canvas on current mouse position

I'm attempting to create a air hockey type game with HTML5 canvas and JavaScript, using Box2dWeb for the physics calculation. I need a way to draw the puck at the current mouse x and y position every ...
1k views

### Kepler orbit : get position on the orbit over time

I'm developing a space-simulation related game, and I am having some trouble implementing the movement of binary stars, like this: The two stars orbit their centroid, and their trajectories are ...
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### AABB implementation

I have seen in some texts and tutorials on the web where an AABB is implemented as a position vector and then half-width and half-height vectors. What is the advantage in using the half-width and ...
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### Unity - Mecanim & Rigidbody on Third Person Controller - Gravity bug?

I'm working on a third person controller which uses physX to interact with the other objects (using the Rigidbody component) and Mecanim to animate the character. All the animations used are baked to ...
164 views

### Simple collision detection in Unity 2D

I realise other posts exist with this topic yet none have gone into enough detail for me. I am attempting to create a 2D game in Unity using C# as my scripting language. Basically I have two objects, ...
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### Calculate velocity of a bullet ricocheting on a circle

I made a picture to demostrate what I need,basecaly I have a bullet with velocity and I want it to bounce with the correct angle after it hits a circle Solved(look the accepted answer for explain): ...
1k views

### How can I simulate shattering glass?

I need to make a simulation with stone thrown through a glass window. How can I accomplish that? I mean, I was thinking about making a 3D model of a stone and glass in 3D Studio Max 2012, shatter the ...
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### How can glass breaking effect from Smash Hit be achieved? [duplicate]

I saw Smash Hit the other day and was amazed by the physics of the game, specially the shattered glass effect: I've read other posts about this subject but I still feel that they don't share enough ...
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### Is Physics a prerequisite to learn Unity3D

I have got a basic knowledge about the Unity 3D platform but I coding in Unity has not been that easy for me. For the simple reason I can see is, I cannot understand which function to use for what ...
108 views

### What torque should I apply in Bullet to maintain a vertical orientation?

I have a RigidBody in Bullet. Each frame, I want to apply torque to correct its orientation toward an upright position (i.e. near-zero pitch and roll). I know its angular velocity and orientation. ...
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### Bullet - objects falling through

I have problem with bullet collisions. You can see problem on this video (around 0:18): http://goo.gl/DiVP8l Objects are "embeded" inside vertical bars - that is not correct - they should be ...
102 views

### Consistent Space Gravity Simulation

I have done some reading into this subject but haven't been able to come to a conclusion that I'm really satisfied with so far, so here is the situation. I have a game set in space, its top down and ...
157 views

### Integration error in high velocity

I've implemented a simple simulation of two planets (simple 2D disks really) in which the only force is gravity and there is also collision detection/response (collisions are completely elastic). I ...
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### Irregular oval collision detection

I am using a physics library based on the Bullet physics engine. How do I create an egg shaped object or a cylinder where the width differs from the depth (i.e. with an oval shape)? I'm not looking ...
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### What is the appropriate way to implement wobble/balance mechanics in Unity 3D?

We are trying to implement a minigame where the player character sits on a bouncing ball, and needs to a) hit forward to move forward and b) hit left/right to adjust against the the ball's natural ...
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I'm would like to achieve something like Object A will jump to position A in parabolic way. For example: I am able to make the object jump but i do not know how to calculate to make the object jump ...
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### How to run physics simulation in the background for possible future outcomes?

I'm designing a physics-heavy game in 3d. The core mechanic of this game is that the user gets to choose his actions based on probable future outcomes. For example - the player has a choice whether ...
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I am stuck on the code for couple of days but couldn't figure it out. Therefore I turned out to look the answer here but couldn't find any that match the requirement Hope some One might help here is ...
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### How can I implement a more realistic momentum system in Unity 4.5?

I'm just starting out with Unity and am making a simple environment where there is a sphere and a ramp. When the sphere approaches the ramp everything is fine. As soon as the sphere hits the ramp is ...
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### How do you properly implement level boundaries in a physics room?

I have an issue with creating a proper boundary in GameMaker Studio when using a physics enabled room. My room has a gravity of 0, as it is in Space. My player object has the default values, but a ...
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### Character animation in physics-simulated environment

What are the standard solutions for animating characters in physics-simulated environments? Let me explain what I mean - in most games characters are pretty much excluded from physics simulation - ...
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### Character bounces/stutters down hills

I'm using Unity3D (not 4) and I'm experiencing a bit of a problem with character movement. I'm using a cylinder as a First Person player with a child Main Camera. In this cylinder is the stock ...
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### Moving multiple hingejoints based on joystick input

I'm controlling a 2D side-viewed (facing right) stickman with a joystick. The movements are fairly intuitive: Joystick down -> Stickman crouches down Joystick up -> Stickman stretches out ...
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### How do I resolve a sphere-triangle collision in a given direction?

I am trying my hand at game physics. I understand that the basic way to pull back a sphere when it collided is to negate the penetration distance: // If collided... // `distance`: distance form ...
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### Timestep schemes for physics simulations

The operations used for stepping a physics simulation are most commonly: Integrate velocity and position Collision detection and resolution Contact resolution (in advanced cases) A while ago I ...
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### Best practice for organizing the physics of objects?

Apologies because this is a long post and I am inexperienced. I would really appreciate the input from some experienced developers. These are my two goals for this project: To learn the best ...
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### Resolution independent physics

I'm making a game like Doodlejump but don't know how to make the physics scale on multiple resolutions. I also can't find anything related to this on Google. Right now I'm scaling the game using ...
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### PhysX - Revolute joint around unit vector

I'm using a right-handed coordinate system with (0,0,-1) = forward, (1,0,0) = right and (0,1,0) = up. PhysX version is 3.3.0. I have a unit vector which represents the axis around which my actor is ...
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### How do I make my camera follow a Box2D object?

I'm implementing a camera in my game. It worked for regular objects, but I began using Box2D and obviously things changed a bit. I have a Body object that I want to draw at the center of the screen. ...
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### Why are my Box2D wheels slipping on ground?

I have a car, set up in Box2D as a rectangle connected with two wheels using WheelJoints: The wheels are defined as follows: FixtureDef wheelFixtureDef = new FixtureDef(); ...
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### Can I jump from A to B?

I'm making some rudimentary AI for my side-scroller and I need to know whether an AI unit can reach point B from point A simply by taking a jump. Flight trajectory of my characters is a bit unusal as ...
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### CCTextField won't appear

I can't seem to add a CCTextField in my physics node, I tried all different methods, but it's still not happening. Here's my code: CCTextField *tf = [[CCTextField alloc] init]; tf.contentSize = ...