Rigid body dynamics is the simulation of physical objects which are "solid" and cannot deform or change shape during simulation.

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Difference between Update method and FixedUpdate in Unity?

i am starting to learn Unity3d and one of the confusion i get is difference between Update() and FixedUpdate(). I am following Lynda Unity 2D game development tutorial there, the instructor uses ...
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5answers
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Why do objects interpenetrate in this simple collision solver?

The code below is from a Microsoft XNA sample here. This is quite a simple rigid body simulation that ignores many physical effects (such as angular momentum), but it does try to push objects ...
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429 views

Calculating impulse propagation through a rigid body after a collision

I'm working on a game. I need to work out what the impulse is at different points on a body as a result of a collision. For example, in the following diagram, if there is a collision that results in ...
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1answer
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How can I implement fixed joints in a 2D physics system?

I'm developing a simple, 2D physics system to complement an entity/component game object framework. So far, I have implemented some basic, tutorial-level physics. An entity that is affected by physics ...
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1answer
12k views

How to detect collision in Unity3D without rigid bodies?

The target platform of my game is mobile devices therefore I try to develop it performance oriented. It will be a strategy game so I don't really need physics in it, consequently I did not add ...
4
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3answers
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Kinematics of a die roll?

I'm working on a simple 3D game. In the game, sometimes the players have to roll die (a D8 to be exact). I wish to represent the rolling die with a 3D model, and I'd like to animate it in 3D space as ...
4
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2answers
458 views

Creating stable tentacle structures

I am using verlet integration to simulate some tentacles. So far it works great and I am satisfied with how it looks in general. Here is how a tentacle is built: The very stiff sticks are colored ...
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2answers
313 views

Procedural generation of physics-enabled structures (in a 2D world)

Is it possible to procedurally generate stable structures out of rigidbody objects at a reasonable runtime speed? Imagine Angry Birds's levels kind of structures but generated procedurally.
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1answer
522 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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3answers
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Unity 4 - Some Rigidbodies Won't Fall Asleep

I'm having this problem in the free edition of Unity 4.1 where rigidbodies aren't falling asleep (and yes, I've tried playing with the sleepVelocity and sleepAngularVelocity values!). I've read the ...
3
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1answer
88 views

Adjusting a skeleton to a Specific Stance

Imagine having a climbing wall and you take 4 adjacent handholds and footholds where together they create a stance. Is there any algorithm or technique with which it would give you a realistic human ...
3
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2answers
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How can I implement revolute (hinge) joints in a 2d physics system?

Further to my previous question on fixed joints, I am now going toe-to-toe with hinge joints in 2D physics. Though the answer to the previous question was excellent, I have come across a few problems ...
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1answer
146 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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1answer
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Understanding Unity3d physics: where is the force applied?

I'm trying to understand which is the right way to apply forces to a RigidBody. I noticed that there are AddForce and AddRelativeForce methods, one applied in world space coordinate system meanwhile ...
2
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2answers
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Getting one rigidbody to follow another, but still react to stuff Unity3D/C#

Basically what I'm doing is having a ball you can pick up and drop on a ramp. When you pick up the first ball, the second ball follows close behind, and when you drop the first ball on to the ramp the ...
2
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1answer
218 views

How can I ensure character weapon is also included in collision detection?

I have two models, my player character and her weapon. Each can be controlled independently (that is, I allow the player to aim the weapon). The object hierarchy is: Character (with ...
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2answers
175 views

Can I make a character solid but not lose non-physics behaviour?

My character can walk around in the world, but walks through other objects, for example a cylinder (stand-in for a cannon). To fix this I added a capsule collider to each of the character and ...
2
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1answer
752 views

Inverse Explosion with Unity2d

I am currently trying to make all other objects push away from the player when the player explodes. It currently works, but it pushes close objects a little and far objects very far. What I want is ...
2
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1answer
74 views

Getting the Volume of an Uneven Mesh

Let's say I have a cube, and that cube breaks apart into 100 different unevenly sized pieces. How can I get the volume of each of those pieces compared to the cube's volume? Using this in order to ...
2
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3answers
365 views

Jumping higher when the player touches a trigger collider in Unity

Im using Unity engine to create a 2D platformer. My character can single/double jump, this works fine everywhere except when i am in range of a collider with a IsTrigger set to TRUE, then my character ...
2
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1answer
157 views

How can I trigger an event each time the rotation of my rigidbody2D is at a given value?

I would like to trigger an event each time my rigidbody2D is at a particular value. The event should only be triggered once for each given value per complete object revolution. Initial attempts at ...
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2answers
61 views

How can I add an impulse to specific rigid bodies at rest?

Scenario Rocks falling down a rocky slope, with a flat surface at the bottom. When they land on the surface, the rocks move slightly before coming to a rest. GLESDebugDraw shows the bright orange ...
2
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1answer
846 views

bullet character controller sliding down any slope gradient

I've been experimenting with the btKinematicCharacterController. I've seen very old complaints that it has issues but I can't find anything recent stating that these issues remain (and nobody ever ...
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1answer
201 views

Physics: calculating angular acceleration in world vs local space

I have a pretty simple rigid body simulation written in Python. In my code I calculate the angular acceleration using formula: angAcc = torque * inertiaTensor^-1 (note row-major matrix order) Now, ...
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0answers
598 views

Why does my RigidBody collision fail depending on which entity is moving?

I am working on a UDK project and have a collision problem. I have a Crate which is a kActor with RigidBody physics and my player who is a Pawn. When my player moves and collides with the crate, the ...
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0answers
269 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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2answers
631 views

How to freeze rotation with a Rigidbody 2D? [closed]

So I am looking to freeze rotation in the Y axis on a Rigidbody 2D. I'm not sure how to set this in my code. This is what I have so far, can you point out my errors? public class PlayerMovement : ...
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1answer
4k views

How to slide a non-kinematic rigidbody?

I'm studying Unity3d, coming from a 2d background, and I'm a bit confused how some things work. I'd like to slide a non-kinematic rigidbody, i.e. "just move it forward", like if it was hovering over ...
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vote
1answer
78 views

Lots of bouncing balls sink into each other [closed]

I'm trying to model a system that simulates an arbitrary number of bouncing balls with some gravity. So far I've come up with a solution that can be seen here: ...
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1answer
61 views

How could I get composite rigid body into unity

I am developing a game, in unity, that has accurate destruction physics and from my understanding unity uses plain old rigid body physics. I was wondering if there was a way to bring composite rigid ...
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1answer
108 views

Warp GameObject Size When Entering/Leaving Area

Below I have an image describing the desired functionality I am going for. Let's say you control a square and when you move this square into a given area, any part of your rigidbody/model inside of ...
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vote
2answers
672 views

Jump without bouncing in physics engine

I am using Ogre3D as my rendering API, and OgreBullet as my physics engine. I have an test entity that when the y part of the velocity is 0 and spacebar is pressed, the velocity changes to, lets say: ...
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1answer
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Strange behavior of RigidBody with gravity and impulse applied

I'm doing some experiments trying to figure out how physics works in Unity. I created a cube mesh with a BoxCollider and a RigidBody. The cuve is laying on a mesh plane with a BoxCollider. I'm ...
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2answers
352 views

Dynamic body implementation

I am writing a 2D game where one of the characters has some very particular requirements. This character is a body with no particular shape (similar to a fluid, but not so much), it has to be able to ...
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0answers
65 views

Should I compute impact damage with energy or momentum?

My game uses physics (Box2D in particular). Just about every object in the game can be destroyed, and the primary method of combat is by slamming objects into one another at high speed. It makes ...
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3answers
171 views

Colliders for moving inside a spaceship when the whole spaceship is made of a single mesh (in Unity)

I've begun to study a unity engine in one purpose: I have a great multi player game idea! The main essence: In space there are two (or even more) huge spaceships with crew consisted of players (all ...
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1answer
127 views

Increasing friction or Adding force relative to transform position in Unity 2D?

Back again with a quick question! I have a few basic platforming mechanics going on in this scene. I have a prefab platform with an animation that loops back and forth between two different x ...
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2answers
74 views

unity3d - Object keeps falling down

I have an object that moves towards another object using this line : transform.position = Vector3.MoveTowards(transform.position, target.transform.position, speed * Time.deltaTime); this is it's ...
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0answers
146 views

Rigging Skinning of human skeleton skin mesh scanned by MRI

I have successfully developed a system in Qt/C++ for human musculoskeletal mocap simulations. I can run asf, amc, bvh motion capture files and can visualize the joint transformations. I even simulated ...
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1answer
83 views

Understanding HingeConstraint in jBullet

I'm using the java port of BulletPhysics engine jBullet. I'd like to make a joints between 2 triangles so that one edge of the first and one edge of the seconds act like a hinge. But I don't ...
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0answers
105 views

unity4.3 rigidbody2d unexpected force behaviour

So guys ive edited the question and here is what my problem is i have a player which has a rigidbody2d attached to it.my player is able to doublejump in the air nicely and stick to walls when ...
0
votes
2answers
10k views

How to move rigidbodies

Have i understood this correct: If i want to use a rigidbody for physics then i should not move an object through its transform.position. I should never move it by riigidbody.velocity since i then ...
0
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2answers
45 views

What are the common methods for achieving dynamic asset destruction? [closed]

I am trying to determine the most appropriate destruction solution for an online desktop game. There are two main factors here that I am considering; 1) the performance of the approach taken and how ...
0
votes
1answer
63 views

An Object is moving but its velocity is 0

In Unity 5 I have an object move when I press a button, force is added as seen by the code below. Then once this force is added I print out its velocity. The problem is that in the console my first ...
0
votes
1answer
48 views

Unity gravity not effecting everyone like it should

so My problem is a bit weird. I have a model that will not fall at the correct speed. She falls incredibly slowly. This is the only script attached to her, and I did the "Scale to large" test by ...
0
votes
2answers
64 views

unity2D Top-Dow Mobile rigibody2D

im using this code for my 2D TopDown mobile player movement.but when i move player With UI Image buttons player keep moving.it didnt stop.and also player starting of move he is very slow. the he ...
0
votes
1answer
1k views

Repelling a rigidbody in the direction an object is rotating

Working in Unity, I have a game object which I rotate each frame, like so: void Update() { transform.Rotate(new Vector3(0, 1, 0) * speed * Time.deltaTime); } However, I'm running into problems ...
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1answer
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Very less vertical transformation

Im using pretty basic code here charcter.transform.Translate(Vector2.up * speed * Time.deltaTime); Im using rigidbody 2d and I'm creating a platformer. When i press the button the character ...
0
votes
1answer
370 views

OnCollisionEnter2D incorrect contact point?

I am trying to shoot a bullet (rigidbody2d, boxcollider2d) to another enemy object (rigidbody2d, kinematic, circlecollider2d). I want the collision point between these two. When they collide, i want a ...
0
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1answer
484 views

Can't go above max speed with RigidBody2D.AddForce()

I'm having trouble making a character move faster than a certain limit using RigidBody2D.AddForce(). My game is a top-down 2D game (constrained to the x/y plane). I'm using a float 'MovementSpeed' to ...