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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45 views

Gravity Simulation failing at short distances

I have a 2D space simulation with gravity acting on three bodies (e.g. sun and 2x planets). The simulation seems pretty stable with RK4 (was unstable with Euler). The problem arises if the orbit of ...
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1answer
582 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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212 views

How do I compute the angle between a pixel on an irregular curve and a circle colliding with it?

I'm building a custom physics engine to accompany a level-editor. This image shows how the level-editor outputs levels: Now, some explanation is in order. The curve is defined by the red points. ...
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296 views

Friction due to gravity in an impulse based physics engine

In my physics engine, I'm using impulses to solve collisions. I'm basing all calculations on these equations: impulse = desired_velocity_change * mass impulse = force * time friction_force <= ...
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0answers
88 views

What is the most effective way to create a set of collision points for an aribitrary mesh?

In my project I am working on automatically deforming an arbitrary mesh with respect to another arbitrary mesh, within the context of user generated content, similar to this deformer being developed ...
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70 views

How do I implement realistic recovery from weapon recoil?

I want to create an equation determining how fast a gun recovers back to its center after it has fired. I have a weapon system functioning based on constants (recoil amount, bullet spread, etc.) ...
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370 views

Getting child collider when collision occurs in compound object in unity3d?

I have a compound object. The parent of the compound object hierarchy has a script that is listening to the OnTrigerXXX callbacks of the children. When this compound object collides with other objects ...
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52 views

Manual response when 2 shapes made of rectangular volumes collide

I have 2 compound objects made of rectangular blocks. One of them (the one that is moving) has a script that listens to OnTrigger callbacks. What I need is to position the moving compound object on ...
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145 views

How do I detect collisions between a particle-based net and a ball?

I've implemented a net using Verlet integration and many points connected with constrains; like this demo, but in 3D. I want to implement collision detection between this net and a ball (like in a ...
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58 views

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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71 views

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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49 views

Bullet Physics ConvexDecomposition?

I've looked at Bullet Physics ConvexComposition Demo and would like to implement that in my game but the code is so undescriptive and it's hard to understand what is going on. Would any of you people ...
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182 views

How do I combine multiple squares into one Tetris block?

I am learning Phaser by making a simple game—Tetris. I'm having difficulties: Can I use simple rectangles as tetrominoes or they should be sprites? I don't know how make the figure's block ...
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101 views

How do you calculate the rate of rotation using the accelerometer values in Android for a particular axis?

I am developing a simple game which involves a character moving up and down only along the Y axis. Currently I am using the accelerometer readings to change the Y velocity of the character. The game ...
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111 views

How to aim with a spaceship in 3D considering its angular momentum?

So I have a spaceship and I have 6 degrees of freedom. At a given moment the following vectors are known of the spaceship: Local forward. Local up. Local sideways (may be implied from the previous ...
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1k views

Why do restitution values less than one still cause infinite bouncing in Box2D?

I'm currently trying to implement basketball bouncing into my game using Box2d (jBox2d technically), but I'm a bit confused about restitution. While trying to create the ball in the testbed first, ...
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0answers
188 views

How do I implement a physics gun?

I'm currently trying to implement a physics gun for my game. What I want is for the entity to stay in the same position on the screen no matter how I wiggle the camera about, what is the correct way ...
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926 views

Unity3D: collider performances on mobile iOS devices

I'm experimenting with Unity3D and colliders. Unfortunately I still don't have Unity Pro version and I can't use the profiler. Consider the following situation: mobile devices (ios, iphone 3GS). an ...
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142 views

Collision shape and Model problem

I used BEPUphysics for my XNA 4.0 game , the problem is that I load my model.fbx from into the game then add it to the space of physics engine , but when I change the scaling matrix of my Model then ...
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749 views

Unity3d Gravity script issues

I'm try this script out http://wiki.unity3d.com/index.php/Gravity and I'm having some issues with it (it seemed to work when I tried it with an old version of unity) the first issue is of ...
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208 views

Updating physics for animated models

For a new game we have do set up a scene with a minimum of 30 bone animated models.(shooter) The problem is that the update process for the animated models takes too long. Thats what I do: Each ...
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303 views

Need help with objects moving toward the player

I am making a 2D game with simple "gravity": everything is just pulled toward 0,0. The speed at which they accelerate towards it is GravityAcceleration up to MaxGSpeed. I also want the player to be ...
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389 views

How do I properly use multithreading with Nvidia PhysX?

I'm having a multithreading problem with Nvidia PhysX. the SDK requires that you call Simulate() (starts computing new physics positions within a new thread) and FetchResults() (waits 'till the ...
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494 views

Joint constraints in PhysX

I'm trying to use PhysX for my physics engine. I'd like to use spherical joints, but I'm having trouble with the constraints. All of the examples that I've found refer to SDK v2.8. I'd like to ...
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22 views

JBullet move object rigidbody in code?

I am trying to move an object's Transform (of a coded class, these are for the rendering engine), then convert it into a JBullet Transform. After that, I try to apply any movement to the JBullet ...
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17 views

Leapfrog integration vs Euler integrator

I am looking at various integration methods for my n-body simulation and I'm slightly confused about actual implementation of leapfrog integration. According to the wikipedia page leapfrog method is ...
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83 views

Anti-Roll bar doesn't work

I'm making a racing game in Unity that has trucks as vehicles. For the truck movement, I'm using WheelColliders. After some testing, I found out that after a certain speed (~60km/h), turning made the ...
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46 views

How can I handle ball interaction with lanes in a pinball game?

In a pinball game, how can I handle collision or constraints on the ball for convincing movement on those highway rails/tracks? I assume using physics and a mesh collider would not work, even when ...
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46 views

moving a character in sprite kit

So I've created a game in which a number of tiles are created from a txt file to create a level for the player to navigate through, but I'm having trouble moving the player. func ...
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40 views

Stuck on a steering problem

i'm building a car game, and currently working on the steering. i would like to change the motion of Z rotation so that the car rotates around the Z axis when the wheels are turned. I can't set the ...
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39 views

How to get rid of “ghost mode”?

I've got few Spatials (mostly boxes) in my space. Player is able to move main Spatial using mouse or keybord. But now every Spatial can go through another. Like in a ghost mode. How can I get rid of ...
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51 views

Calculate hit-normal from collision

I am trying to implement a swept test collision between an AABB and a Line Segment and I found this implementation working great ... Except that it doesn't cover how to calculate the hitNormal and ...
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20 views

Impulse resolution with varying time delta

I thought I'd try building a basic 2D physics engine, and I'm currently writing the impulse resolution part of it (yeah, not very far into this). Using quick internet tutorials like this as a guide, ...
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48 views

Calculation technique for 2D inertia tensors?

Just wondering what the techniques are out there. It's only 2D so I figured there'd be a good chance for there to be a "one size fits all" solution out there that's essentially an analytical solution. ...
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35 views

How do I apply Farseer Physics Engine Collision on my image? I tried it on my codes and it is not working

How do I apply Farseer Physics Engine Collision on my image? I tried it on my codes and it is not working. PoolGameSingle poolgame = new PoolGameSingle(); var cue = poolgame.CueStick; ...
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115 views

How to determine velocity from force

I recently started a project with the intention to master the physics aspect of Unity. Although I have a good knowledge of Unity, I never had the opportunity to work on game that makes extensive use ...
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33 views

Applying angular velocity distorts model

I am calculating the orientation of a sphere through the following code wV = new Vector3(0, pi/2, 0); w = new Quaternion(wV, 0); // o is the current Orientation o.Normalize(); w = 0.5f * w * o; // dt ...
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65 views

How to get yaw of bullet physics vehicle?

I am using the Bullet Physics port to java, JBullet, and am trying to render a vehicle body that i created in Blender on top of the vehicle chassis. Since i cannot effectively find a way to render ...
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183 views

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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90 views

Implementing a group formation behavior

I am trying to implement a group formation behavior where all the units in my group follow a leader and maintain their position throughout. So far I am able to move them, rotate and follow the leader. ...
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81 views

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 ...
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58 views

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 = ...
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134 views

Box2D collision damage calculation from postSolve or not?

I'm using postSolve to get impulse then calculate damage base on that impulse. But there's some issue: Stability The damage isn't stable. When the same ball is hitting with same speed, the damage ...
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188 views

Realistic collisions with a kinematic rigidbody?

I have a car game where player drives a car; this car has a collider and a kinematic rigidbody attached and is completely controller by script (i.e. a script sets its position and rotation). In the ...
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67 views

setChaseEntity freezes or jitters the AnimatedSprite

I'm trying to implement setChaseEntity method in a physics based app. I wrote the below code which has an animated sprite ans as the player. The player is movable and it can jump. When i try to focus ...
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0answers
150 views

How to find correct offset to adjust sprite to the position of box2D body after rotation

I am trying to implement phsyics with the as3 box2d port. I currently have a b2body for each of some certain sprites in my game and I am able to update the sprite's positions correctly from the ...
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175 views

How to design basic physics and movement behavior for 2D platformer?

I want to make a simple 2D platformer. I know some basic 2D physics and how to implement them in a game. How to make a character jump, accelerate, decelerate, etc. But I have no idea how to actually ...
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0answers
20 views

Handling gyroscope data

I'm working on a mobile game that allows user to rotate player around an axis using accelerometer. In addition to that, to allow fast, almost instant, rotation I thought of using gyro data. It seems ...
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55 views

Lateral Friction Phisics

I am trying to create a physics engine for my game, and need to cancel out any lateral velocity for when entities turn. I have tried to mimic this page's example, but it is not working. I have objects ...
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299 views

Farseer: Difficulties with implementation of DebugView

I added the project "Farseer Physics Engine 3.3.1 HelloWorld XNA\DebugView XNA\DebugView XNA.csproj" to my solution explorer in Visual Studio. In addition, I added a reference to my project and the ...