# Tagged Questions

Software for simulating physics like collisions, forces, mass, joints, motion etc. Examples of physics engines are PhysX, Havok, Bullet and ODE.

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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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### Applying angular velocity to quaternion

I am reading Game Physics Engine Development by Ian Millington currently. In his book, he represent an orientation of rigid body by quaternion. I don't understand the formula where he apply angular ...
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### Cloth effect to boned model for XNA

I'm currently working in virtual dressing project using kinect. I'm using a dress model with bone created in blender and added that to xna, placed on the customer and controlled the product movements ...
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### 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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### 2D Platform physics system with deltaTime

I'm implementing my physics handler in my own 2D "Platform" game. My main problem is that when the timestep ( deltaTime ) changes, maybe to some tiny lag spike or something like that, the running ...
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### Bullet Physics: Applying a force at the point of collision

Suppose I want to simulate some kind of gripper with two "fingers" (such as pair of pliers, or two-fingered robot hand), picking up an object from the ground. Both the gripper and the object are ...
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### p2.js physics engine behavior on Heightfield

I am writing a small game consisting of a 'ragdoll' character riding a skateboard. I have created a 'skateboard park' with some ramps and a jump. I am using a 'heightfield' object as the ground. ...
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### Where are the parameters to APEX destructible asset / actor documented?

The NxDestructibleAsset has parameters such as defaultBehaviorGroup.damageToRadius destructibleParameters.fractureImpulseScale p3BodyDescTemplate.density structureSettings.useStressSolver ...
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### Storing rigid body collision shapes in local or world coordinates

I'm writing the beginnings of a lightweight 2d rigid body engine (in javascript, as a hobby project), and i'm debating whether to store collision shapes in local or in (updated as needed) world ...
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### Mobs living in the physics engine

So, yeah. Mobs (including, and indeed especially, the player), physics engine running (cannon.js), first-person perspective, fairly low-poly-count world because I'm targeting WebGL. I'm trying to ...
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### 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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### Bullet Physics: 2dArray into Collisionshape

I'm fairly new to bullet physics and I am wondering how to make a collisionshape out of an 2dArray(x,y) with height informations. I figured out I have to use either btBvhTriangleMeshShape or ...
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### btCompoundShape representation of a table not functioning normally

I've been working on a small "game" on the side to develop my game programming knowledge. I put game in quotations because there's really no objective, it's basically just a room filled with tables ...
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### Weird Collisions in ODE

I'm trying to get a basic OBB/OBB Collision System working. For this I use ODE. My problem is: Whenever I use the dSpaceCollide and pass in my Space and my Callback, my Callback shows me, that a ...
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### JBullet is acting weird, what is causing these 'floating' rigidbodies?

I've been working on a 3D game engine in Java for a school project. The game engine had scenes containing game objects, these game objects contain components defining the behavior of each object. I'm ...
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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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### scaling ccsprite and ccphysicsbody

The player which is scaled down (after few seconds as game progresses) but its associate body is not being scaled down. I have create a Player object with SpriteBuilder with following details:\ ...
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### Endless sidescrolling skating spritekit game

I am developing an endless side scrolling game in spritekit. For parallax background scroll : - (void) update:(NSTimeInterval)currentTime { [self.children enumerateObjectsUsingBlock:^(SKNode * ...
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### Cocos2d-x 3.7 PhysicsBody velocity issue

i have a Sprite with physicsBody,and fixed velocity,the problem is the sprite is not renderd smoothly with the mouvement,it's look like zigzaging forward and backward with a tiny fixed offset,but keep ...