Bullet is a professional, free 3D Game Multiphysics Library that provides state of the art collision detection, soft body and rigid body dynamics.

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Bullet 3D Physics Objects Not Rotating?

So I've got Bullet 3D controlling the motion of objects rendered with DirectX. In the clipping below I've got 2 identical rectangles & 5 balls. The lowest rectangle has a mass of 0 and doesn't ...
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2answers
1k views

How to implement a simple bullet trajectory

I searched and searched and although it's a fair simple question, I don't find the proper answer but general ideas (which I already have). I have a top-down game and I want to implement a gun which ...
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0answers
62 views

Bullet Physics ConvexDecomposition?

I've looked at Bullet Physics ConvexComposition Demo and would like to implement that in my game but the code is so undescriptive and it's hard to understand what is going on. Would any of you people ...
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1answer
406 views

Using Bullet physics engine to find the moment of object contact before penetration

I would like to use Bullet Physics engine to simulate the objects in 3D world. One of the objects in the world will move using the position from 3D mouse control. I will call it "Mouse Object" and ...
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2answers
1k views

LibGDX - draw bullet physics bounding box

I am very new to game development and I am trying to debug my 3d collision bounds. Could somebody give me an example on how to draw the collision bounds of an object in libGDX? I assume it has ...
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1answer
62 views

Bullet: Get steepness or slope between positions

In a CharacterController object, there is setMaxSlope(btScalar slopeRadians) The max slope determines the maximum angle that the controller can walk up. But how about knowing it in advance? Like ...
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0answers
306 views

Quaternion - rotating rigidBody to particular angle over time

Using Bullet Physics. There's a rigid body that is rotated. For some delta-time I need to rotate that body to have rotation of (0, y, 0) - keep the old y value rotation but reset x and z. The ...
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1answer
979 views

Conceptual - What is the optimal way to combine steering behaviors with rigid body physics?

I am working on a simple 3D space simulator that makes use of the Bullet physics engine. The spaceships are rigid bodies that have a mass and hitbox so that they can be considered for collisions. At ...
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1answer
241 views

Bullet softbody nodes messed up positions [closed]

I recently switched from Havok physics to Bullet because I wanted to have soft body collisions, but I don't have any budget to license the (superior?) Havok solution, I couldn't even try those ...
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1answer
442 views

What are the parameters for btHingeConstraint::setLimit

What does each parameter in btHingeConstraint::setLimit do to the hinge constraint? void btHingeConstraint::setLimit ( btScalar low, btScalar high, btScalar _softness = ...
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1answer
138 views

Bullet3: Issue with applying force once an object is at rest

I just started using bullet and I'm having an issue where once my rigid body is at reset at the floor it won't move when I apply a force to it. I have created a small demo to show this using the ...
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1answer
825 views

How to draw a plane equivalent to a given btStaticPlaneShape using OpenGL

With all other shapes in bullet, you can easily get the transform from the MotionState which holds the origin, the scale, and the rotation. There seems to be no way to get the same information about a ...
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1answer
150 views

x-inverted obj importer in BulletSharp - whats wrong?

See importer C# code at the repository. Screenshot: Left: bullet imported version, right: correct 3ds max version. It's somehow inverted. If you think that left part is just 180 degrees rotated you ...
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1answer
297 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) ...
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2answers
466 views

Spherical / Relative Gravity

I'm working on an Ogre3D + Bullet project that involves planets in a solar system. For all intents and purposes, I'm looking to give each planet it's own gravity sphere. So far, all I've found are ...
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1answer
691 views

How to use Bullet physics with Entity Component Systems?

I have an Entity Component system and I want to have a Physics Component that would add the given object to the physics simulation. My problem arises because the Bullet API requires me to add each ...
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1answer
952 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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0answers
48 views

Bullet simulation stops after windows inactivate

I am having trouble when inactivating window (event resizing); all the contents get rendered and input works. Even the physics work but the btDiscreteDynamicsWorld stepSimulation function does not get ...
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2answers
353 views

Best collision shape for rooms

I'm wondering what is the most efficient collision shape to use with APIs like Bullet or Havok for rooms/interiors. Rooms tend to be boxes but are concave since the normals point inward which means no ...
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1answer
728 views

how to predict enemy postion to shoot bullet same kingdom rush

i'm doing a tower defense game same kingdom rush, enemy can run curve not only linearly. i found this link : 2D tower defense - A bullet to an enemy but this link use only for enemy run linearly. ...
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0answers
555 views

Bullet Physics Simulation Running Slow

I'm in the process of converting my game engine from java which used the LWJGL and JBullet to c++. However, when I was implementing Bullet physics my simple simulation of a box dropping from specified ...
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1answer
478 views

Bullet physics weird behavior. Jittering and drifting with btBoxShape

I'm dropping a simple box onto a plane from 100 units and my solution using Bullet Physics is giving me some weird behavior. The dimensions of the box are {2, 4, 1}. When the box hits the ground it ...
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1answer
655 views

Create a physics body with hole : bullet physics

I am writing an iOS game, using bullet for physics, blender to create models, cocos3d as the game engine. I have a model like this Basically there is a plane, with a hole, and a UVSphere. Both were ...
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2answers
3k views

How to set the object's world position in bullet?

In my Ogre3d application I am first changing the parent of a node like this: // save object "Cube" into node*; then ... Vector3 absPos(node->_getDerivedPosition()); Quaternion absOrient(node->...
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1answer
44 views

Stick 2 btRigidBodies together

I have a platform with btBoxShape as shape, and I want to rotate it every certain amount of time to simulate a rotating platform. Right now I rotate it with Ogre (my rendering engine) and use a ...
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1answer
2k views

Bullet physics debug drawing not working

Background I am following on from this question, which isn't answered yet. Basically I have a cube and a UVSphere in my scene, with UVSphere on the top of the cube without touching the cube. Both ...
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1answer
2k views

Create bullet physics rigid body along the vertices of a blender model

I am working on my first 3D game, for iphone, and I am using Blender to create models, Cocos3D game engine and Bullet for physics simulation. I am trying to learn the use of physics engine. What I ...
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1answer
1k views

Detect when a bullet rigidbody is on ground

I have a rigidbody that is on top of a plane or another rigidbody. How do I check if said rigidbody is on top of it? I tried to check the Y-part of the velocity but it is never 0, it is always a ...
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2answers
780 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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2answers
710 views

How to correctly create bullet rigid from custom .mesh in Ogre?

Being new to 3d programming and bullet physics in particular, I am wondering how a 3d model or the mesh generated out of it effects the accuracy of bullet physics simulation. I have written a ...
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1answer
384 views

Need help with a complex 3d scene (using Ogre and bullet)

In my setup there is a box with a hole on one side, and a freely movable "stick" (or bar, tube). This stick can be inserted/moved through the hole into the box. This hole is exactly as wide as the ...
3
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1answer
351 views

What are “frame A” and “frame B” in btGeneric6DofConstraint's constructor for?

I have a very simple (and maybe too primitive to post here but I’ll try anyway :P) question about Bullet constraints. What are arguments const btTransform &frameInA, const btTransform &...
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5answers
2k views

How to save and restore Bullet Physics state?

I'm looking for information on how to save the runtime state of rigid bodies with Bullet Physics. Most of my world consists of static objects, but I have a few dynamic and kinematic objects as well. I ...
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2answers
2k views

First person camera with Bullet Physics

Before integrating the Bullet Physics, the camera worked fine. But instead of using my own simple struct for transform data, I use rigid body structs provided by the physics library now. There are ...
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1answer
56 views

How to squash stretch the Bounding box so as to get Good Physics effect

I have Surrounded a game Object with a rectangular Box and applied Physics properties to that Box so that load on the computation gets reduced. But i have a problem, whenever in animation if the Game ...
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1answer
768 views

Bullet physics: how to make a soft body “static” (kind of)?

I'm fairly new to Bullet and started using it a week ago. I mainly played with rigid bodies and everything works as expected but now that I also need to add soft bodies into my simulation, things got ...
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1answer
4k views

How to implement bullet physics in libgdx

I am new at game development want to know that how can I implement bullet physics in libgdx. I searched lot of things on Internet but nothing found worthy.
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2answers
786 views

Distance between two objects?

We are trying to determine the distance (a scalar, double) between two objects' surfaces in Bullet. We are new to the Bullet engine, and we've been looking into the demo projects, but couldn't find ...
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2answers
662 views

Choosing a correct collisionshape for a voxel engine

I am building a voxel engine on Ogre with bullet as a physics engine. I separated my blocks into chunks to help batch together render calls. At the moment, each chunk's physics is handled by a ...
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1answer
690 views

How can I extend btCollisionAlgorithm to enable collision with a voxel terrain?

I am using Bullet, and am attempting to make a collision algorithm that generates contact points off of a cube-based terrain along with the appropriate collision response. I also plan to extend this ...
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1answer
1k views

Bullet Physic: Transform body after adding

I would like to transform a rigidbody after adding it to the btDiscreteDynamicsWorld. When I use the CF_KINEMATIC_OBJECT flag I am able to transform it but it's static (no collision response/gravity). ...
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2answers
419 views

How to account for speed of the vehicle when shooting shells from it?

I'm developing a simple 3D ship game using libgdx and bullet. When a user taps the mouse I create a new shell object and send it in the direction of the mouse click. However, if the user has tapped ...
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2answers
2k views

What is the best way to check if there is overlap between player and static, non-collidable items in bullet physic engine

I'd like to add non collidable objects (eg: power ups, items, ...) in a game world using Bullet Physics Engine and to know if there is collision between player and them. Some info : there is a lot ...
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0answers
727 views

What is the best way to implement collision detection using Bullet physics engine and a track generated from a curve?

I am developing a small racing gam, the track is generated from a curve. As said above, the track is generated, but not infinite. The track of one level could fit with no problem in memory and will ...
4
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1answer
491 views

Moving the jBullet collision body to with the player object

I am trying to update the location of the rigid body for a player class, as my player moves around I would like the collision body to also move with the player object (currently represented as a cube)....
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1answer
671 views

Rotating a cube using jBullet collisions

How would one go about rotating/flipping a cube with the physics of jBullet? Here is my Draw method for my cube object: public void Draw() { // center point posX, posY, posZ float ...
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1answer
213 views

jBullet Collision/Physics not working as expected

Below is the code for one of my objects in the game I am creating (yes although this is a cube, I am not making anything remotely like MineCraft), and my issue is I while the cube will display and is ...
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0answers
119 views

colliding btRigidBody objects behave strangely when moving slowly

I'm trying to use Bullet Physics in my iOS game. The engine appears to be correctly compiled in that the demos work fine. In my game I have the player's ship and some enemy ships. They're defined as ...
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1answer
2k views

Bullet Physics - Casting a ray straight down from a rigid body (first person camera)

I've implemented a first person camera using Bullet--it's a rigid body with a capsule shape. I've only been using Bullet for a few days and physics engines are new to me. I use btRigidBody::...
6
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1answer
1k views

Bullet Physics implementing custom MotionState class [closed]

I'm trying to make my engine's camera a kinematic rigid body that can collide into other rigid bodies. I've overridden the btMotionState class and implemented setKinematicPos which updates the motion ...