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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Jump-through & drop-down platform

I'm creating platforms in my game where the player can: 1) Jump through them from the bottom and land on top of them 2) While on top of them, drop down through them I've been able to get #2 working ...
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21 views

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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14 views

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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1answer
106 views

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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61 views

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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1answer
226 views

Collision between a sphere and a mesh(height-map)

I am trying to implement a method that detects the collision between a sphere and a mesh and reflects the vector of speed. I have a method, that detects a collision between a sphere and a triangle and ...
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51 views

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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33 views

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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65 views

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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2answers
401 views

How to deal with pushing objects out of collision in a physics engine

I'm developing a 3D physics engine (I know, I should use one of the many good existing physics libraries, however my collision detection is optimised for objects with highly ordered highly complex ...
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2answers
478 views

How do I fix objects “popping” or jittering in physics engine?

I've got a simple physics engine that solves collisions by simply correcting the position of overlapping bodies (just circles for now) directly, as opposed to just changing the velocity or applying an ...
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4answers
379 views

What different ways are there to model restitution in a physics engine?

In my physics engine I give a body a value for restitution between 0 and 1. When two bodies collide there seems to be different views on how the restitution of the collision should be calculated. To ...
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321 views

How do engines avoid “Phase Lock” (multiple objects in same location) in a Physics Engine?

Let me explain Phase Lock first: When two objects of non zero mass occupy the same space but have zero energy (no velocity). Do they bump forever with zero velocity resolution vectors or do they ...
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2answers
1k views

How to make a 2D Soft-body physics engine?

The definition of rigid body in Box2d is A chunk of matter that is so strong that the distance between any two bits of matter on the chunk is completely constant. And this is exactly what ...
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3answers
279 views

Sound Synthesis from object collision in Virtual Reality Environment

I have a project whose subject is "Sound Synthesis from object collision in Virtual Reality Environment" First of all, I have to define some objects with certain attributes (like shape, mass, material)...
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1answer
96 views

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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77 views

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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7 views

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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1answer
146 views

Data oriented design in physics engine

I am new to data oriented design and I am currently developing a physics engine as a hobby project. I am really interested in data orinted design but I am not sure how to apply data oriented design to ...
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1answer
173 views

2D Spaceship Thruster Movement - Turning

I have a spacecraft (shown in the image) built out of ‘blocks’ / 3D planes. It is drawn within a 3D space, but I’m ignoring the Y axis for now and keeping things on a “2D” XZ axis. The ship has a ...
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1answer
62 views

p2.js body position is NaN when spawned inside of each other

I'm working on a project for which I need a physics engine. At the moment I'm playing around with p2.js but I'm running into a problem: When I try to create multiple bodies (circles and/or boxes) ...
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71 views

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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2answers
76 views

multiple contacts for SAT collision detection

I have implemented SAT algorithm for obb-obb intersection and I am able to generate a contact for this collision type. My problem is that SAT only generate ONE contact and in many situation I need ...
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2answers
404 views

What are the disadvantages of R-Trees in collision detection?

I was poking around in SQLite and discovered R-trees. A little digging revealed that R-trees are really just fancy AABB-trees. Then I realize that the state of the art in collision detection (often ...
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1answer
38 views

Havok Physics : “hkQuaternionf not normalized/invalid!” when hkpWorld::stepMultithreaded()

today I want to ask a question about Havok Physics 2012. My havok version is 2014.1.0-r1 (x86 SIMD version), and I'm using Visual Studio 2012 on Windows 8. My problem is, that once I add a rigid ...
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1answer
46 views

Top view physics engine

For my first game i want to create a topview game in c++ where you can drive a car (like in gta2). As far as i know i dont need any gravity. While doing a bit of research about games they often advice ...
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319 views

Bounding volume hierarchy - linked nodes (linear model)

The scenario A chain of points: (Pi)i=0,N where Pi is linked to its direct neighbours (Pi-1 and Pi+1). The goal: perform efficient collision detection between any two, non-adjacent links: (PiPi+1) vs....
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136 views

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 ...
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1answer
167 views

How does matrix based game physics (collision detection & response) work?

I'm familiar with how to do collision detection and response using shape intersection tests, the separating axis theorem, and by using MPR and GJK with minkowski sums and support vector defined shapes....
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1answer
137 views

Why is the drag force multiplied by the inverse normalised velocity vector?

In pure physics texbooks, I'm seeing this formula to calculate fluid drag force: It is clearly stated that it should be opposite to the velocity. Now to me that means, in pseudocode: fd = get_drag(...
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45 views

Which Box2D-like physics engine parameters need pixel conversion?

The official guide does not have any useful details on the matter: http://www.box2d.org/manual.html Position is an obvious one. What about velocity? Density? Anything else? Update: the context is ...
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133 views

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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1answer
155 views

Rigidbody physics concept: Why translate collision shape on-the-fly instead of mutating it?

Crossposting at http://stackoverflow.com/questions/29993547/rigidbody-physics-concept-why-translate-collision-shape-on-the-fly-instead-of-m I've spent some time going through physics engine's ...
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220 views

How do I calculate rotational impulses in rigid body collisions?

I'm writing a simple 2D physics engine to help me understand the inner workings of physics engines. I'm following Randy Gaul's tutorial which can be found here and It's been extremely useful and ...
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3answers
7k views

How can I make my main character move in a parabolic arc when jumping?

I'm entering Android game development, and I already have a computer version of a game I want to publish. The thing is, I want to make this as good as it can be. With that said, I need a physics ...
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0answers
301 views

Inverse Dynamics How to [closed]

I have some motion capture data (kinect) that records all body joints (32fps) and I want to take particular positions (for example when a person moves both of his hands up in the sky in celebration ...
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1answer
139 views

Understanding constant acceleration in terms of game physics simulation

There are various integration methods that can be used for games. I am trying to write a simple physics engine deciding between semi-implicit Eular and Verlet variants. What I don't understand is ...
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1answer
33 views

How to discern boxes and spheres when importing from fbx

I can import scene from FBX file into my engine, and i want spheres, boxes and capsules to be imported as colliders. So, how i can check if imported instance is one of them? Thanks.
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114 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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3answers
167 views

Do I need to learn any physics if I use a physics engine? [closed]

Complete novice out here. Of course I know basic physics like mass and inertia. I don't want to make an engine I just want to make a game and use a physics engine made by someone else. Do I need to ...
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1answer
5k views

How to achieve highly accurate car physics such as Liveforspeed?

Liveforspeed is a racing simulator, there is amazing amount of realistic physics. for example, tires get warm, tire actually deforms when you turn corners. You need to play this game with a mouse at ...
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59 views

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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70 views

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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1answer
175 views

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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1answer
283 views

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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0answers
598 views

C++ FPS game collision detection with partitioning system or physics engine? [closed]

I'm working on a small FPS game (as a hobby and for learning purposes, nothing else) built with C++ in OpenGL (from scratch). Documenting online on the kind of strategy someone would approach with ...
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1answer
675 views

simple collision detection with box2dweb

im beginner in box2dweb that version of box2d for javascript i wrote simple gravity system and i want to detect the collision between the box and the ground , when the falling box hit the ground ...
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162 views

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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1answer
700 views

Calculating impulse with multiple collision points

In my amateur 2D rigid body physics engine for a game I react on collisions between two bodies with an impulse j (formula 11) as explained here. To calculate this impulse I need one contact point P ...
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411 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 <= ...