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Questions tagged [physics-engine]

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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1answer
42 views

Can an unmodifiable 3D map be one large model or many small models?

Unmodifiable meaning that any ingame actions have no result on the terrain. Like in Source games. Question: Should I export one large model of the map, or should I split it into smaller chunks? If ...
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1answer
204 views

Calculating real time moment of inertia around arbitrary axis in 3d

I have a 3d rigid body consisting of multiple triangles forming a closed mesh. I know how to calculate the moment of inertia around an arbitrary axis by splitting up the mesh into simpler shapes and ...
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1answer
561 views

Looking for collision detection algorithms for broad and narrow phases between non-convex polyhedrons

I have some experiences on particle system simulation (namely DEM - Discrete element method), in which an individual particle with realistic shape (convex and non-convex) is approximated by gluing 3D ...
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0answers
211 views

Bullet Physics Scaling rotational part of 6DoF Spring Damper

I am currently trying to scale up my setup (consisting of two rigid bodies connected by a btGeneric6DofSpring2Constraint) to fall within the suggested dimensions for a concise simulation. In order to ...
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1answer
396 views

Should a bowling game use a 2d or a 3d physics engine? [closed]

I'm creating a bowling game in flash+as3. I'm new to physics engines, so, to start I've begun to learn Box2D since I've heard it's one of the most popular physics game engines. Currently, I'm not ...
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1answer
366 views

How do I prevent a Box2d dynamic body from sticking to static body walls in zero gravity?

I'm still making this air hockey game. I have it mostly there now, but the dynamic body which is the puck always sticks to the walls (static body rectangles that form the border of the table). I read ...
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0answers
373 views

3D Physics Engine Collision Response: Solving Simultaneous Collisions via equation

I have been implementing a basic physics engine for a small game project I'm working on. It has very specific requirements, so I decided to try and write my own physics engine to meet them. I found ...
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1answer
87 views

How to detect and prevent the resolution of fake collisions?

I'm creating my own physics engine and I came across a small inconvenience. Here how it goes: when a body tries to push into something it really can't push, it gets pushed back (which is completly ...
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1answer
1k views

Integrating Unity physics with Entitas

I've used Entitas a bit and it appeared to me as a great way of creating clean, modular code. I've seen few examples of games created with this framework, and most of them were puzzles, TD's, simple ...
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2answers
923 views

What is inertia in a physics engine?

Inertia seems to be useful in a physics engine, so useful that even in Box2DLite, a demo of Box2D it hasn't been omitted. See this Body class from Box2DLite: ...
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2answers
626 views

Physics engine and squishing of stacked objects

I have a general question that seems to apply to most physics Engines (Box2D, Unity, Matter.js, …). I'm trying to make a tower of rectangular objects that are stacked on the [static/mass=infinity] ...
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1answer
572 views

Quake Physics ported to Unreal Engine? [closed]

My eSport mod needs the Quake 3 physics -- as well as some modern engine features. Options are either: Quake Engine: Upgrade/develop new rendering,etc component(s) Unreal Engine: Port physics. ...
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1answer
156 views

Problem resolving rotation between sphere-sphere collision

I have developed a collision detector that return collision data, as collision normal, collision point, interpenetration, etc. And now I am developing a collision solver. The collision solver compute ...
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1answer
318 views

Rigid body falls through static mesh even though collision is detected

I'm using Jitter Physics to create a game. For testing, I have ball (a spherical rigid body) falling onto a small box-like mesh. The problem is that the ball falls straight through the floor, even ...
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1answer
39 views

How to throw b2body with various speed at fixed position?

Above image is for ref to better representation. I have box2d object and i know start point & end point position. Now i want to give any force or impulse such that b2body will first collide at ...
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0answers
60 views

Is this a correct way to solve contact?

Hi there, I'm learning the impulse based physics engine these days. Can someone please check my image about solving a contact( a sphere resting on ground) , and please let me know where is wrong. ...
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2answers
1k views

Circular soft body? Matter.js or other js engine?

I am using Matter.js physics in an attempt to create soft bodies. I was able to create a body like this: However I am not sure if this is the "soft body" I want. It is true that this body is not ...
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2answers
704 views

Rigid body physics resolution causing never ending bouncing and jittering

I'm trying to make a fairly simple, impulse based rigid body simulator as part of a Uni assignment. I'm using bullet physics to perform collision detection, and my own code to perform collision ...
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0answers
182 views

Physics fixed time step with client/server games

I'm trying to make a 2D platforming multiplayer game with client/server system. I want to use Node.js and Phaser for the display. I read a lot about fixedTimeStep : http://gafferongames.com/game-...
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0answers
119 views

(UE4) Simulate physics breaks timeline animation

I'm using timelines to animate my boat object, which does not have any limbs. So all I need to accomplish is rotation and a little movement. However, when the player dies, I need the boat to sink ...
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5answers
7k views

What exactly is a physics engine?

A program should take input, process it and give output. So what exactly does a physics engine take as input and provide as output?
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2answers
527 views

How to get the point of collision in Separating Axis Theorem?

I'm interested in the relatively precise point (not line) of collision for calculating angular velocity on impact for use in a impulse calculation. At first I thought, perhaps naively, that I could ...
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0answers
405 views

How can I create click and drag for a 3D Jenga game in Unity?

Essentially, I am trying to create a game that mimics Jenga. Right now I have made it so that the blocks collide with each other and have gravity, everything works very well. The one thing that I am ...
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1answer
493 views

How would joints work in an impulse-based physics engine?

I want to learn about physics engines, especially impulse-based ones. So I've followed along this tutorial to create some simple rigid-body physics: http://gamedevelopment.tutsplus.com/tutorials/how-...
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0answers
132 views

Integration of Game Loop + Physic Engine : when to delete objects?

How to manage code around physic engine, when a game object should be deleted? I will use a tiny game as an example:- 1st iteration of development I have a very simple game with 1 character (Jumper)...
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0answers
169 views

Collision Detection between two instances of the same Prefab

I am a trying to recreate the first stage of Super Mario Brothers, but I am having a bit of trouble with the collision system between Koopa Shells. I have written two different scripts in hopes to ...
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2answers
413 views

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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1answer
2k 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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0answers
315 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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0answers
520 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 ...
3
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1answer
629 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
1k 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
260 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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2answers
723 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
5k 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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1answer
100 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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1answer
82 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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2answers
2k 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
757 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....
2
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1answer
482 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: ...
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86 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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0answers
218 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 ...
2
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1answer
216 views

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

Crossposting at https://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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2answers
1k 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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1answer
462 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 ...
2
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2answers
499 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 Euler and Verlet variants. What I don't understand is ...
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1answer
47 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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3answers
505 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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3answers
186 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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0answers
108 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. ...