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6
votes
5answers
1k views

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 ...
6
votes
3answers
325 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 ...
4
votes
1answer
6k 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
votes
3answers
811 views

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
votes
2answers
256 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 ...
3
votes
1answer
70 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 ...
3
votes
1answer
78 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
votes
2answers
433 views

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
votes
2answers
770 views

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 ...
2
votes
2answers
244 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.
2
votes
1answer
2k views

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
votes
2answers
613 views

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
votes
2answers
59 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
votes
1answer
163 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 ...
2
votes
0answers
190 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 ...
1
vote
1answer
471 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 ...
1
vote
1answer
1k views

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 ...
1
vote
2answers
261 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: ...
1
vote
1answer
526 views

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 ...
1
vote
2answers
322 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 ...
0
votes
1answer
58 views

making rigid body stop using friction

how am I suppose to apply friction to an object so that when I apply force it decelerates eventually to zero? Here are my physics objects: Rigid Body "Sphere" Collision shape: btSphereShape(0.50) ...
0
votes
1answer
211 views

Unity AddExplosionForce not doing anything

Recently I've started learning Unity3D. I'm working on a game as an exercise in which you control a space ship and have to dodge asteroids. If you feel like it's getting a bit too much you can hit the ...
0
votes
2answers
97 views

How can I simulate a rigid body bounced from a wall in 3D world?

How can I simulate a rigid sword bounced from a wall and hit the ground (like in physical world)? I want to use this for a simple animation. I can detect the figure and the size of the sword (maybe ...
0
votes
0answers
29 views

Calculate mass moment of inertia of two 2D polygons

For a small 2D physics engine I need to know the following. I wasn't able to find an answer even after a week of research. Hope you can help me. I have multiple concave 2D polygons that are tight ...
0
votes
0answers
32 views

Memory Management on Physic Body Frames in Unity

Compared from the Android programming with the help of LibGDX and Eclipse programming software in making 2D physics based game from this previous question, what if I'm throwing lots of game objects ...
0
votes
1answer
85 views

3rd person game with rigid body

Im making a 3rd person 3D game. I have a little capsule shaped player controlled drone at the moment that moves on a flat surface. Y axis is locked. The Game object contains a script and then the ...
0
votes
0answers
35 views

Mixing kinematics and dynamics in ODE

I am trying to do some animations on characters with a variety of body plans. I am trying to make a system that uses IK for moving end effector positions (some of the time), and use the actual ...
-1
votes
2answers
133 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 ...