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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122 views

Best way to load rigid bodies from file

I'm trying to switch to bullet for physics simulation. Lemme just say first that I am so pleased with bullet's accuracy and performance. After messing around it for a bit, I'm now trying to load ...
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0answers
19 views

JBullet quaternion to Euler angle conversion causes strange flipping behavior

I am making a game using JBullet (a Java port of C++'s Bullet library) for the physics and LWJGL for the graphics. However, JBullet measures angles in quaternions and LWJGL uses Euler or ...
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1answer
312 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 ...
2
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1answer
180 views

Bullet physics weird behavior . Jittering and drifting with btBoxShape

I'm working with bullet physics, and I have some weird behavior. What's happening is that as a simple test, I'm dropping a simple box onto a plane from 100 units. It's important to note that the ...
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2answers
84 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 ...
2
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1answer
66 views

How can I use imprecise accelerometer data for controls?

I want to rotate an object with respect to the phone's position. I use the accelerometer output to detect orientation: float roll = Gdx.input.getRoll(); float pitch = Gdx.input.getPitch(); float ...
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1answer
63 views

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 ...
3
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1answer
210 views

How do I run a callback when all objects have stopped moving?

I'm using Bullet and want to take some action once all objects in a dynamic world have reached 0 velocity (or at least a value that's very close). I was trying to iterate over all of them all the ...
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2answers
126 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
38 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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0answers
56 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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5answers
1k 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 ...
2
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1answer
209 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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0answers
39 views

Collision at incorrect height between boxes and btHeightfieldTerrainShape

I'm using btHeightfieldTerrainShape from BulletPhysics for collision between fired boxes and a terrain. But such boxes seem to collides at higher positions above the terrain as the following picture. ...
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0answers
25 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 ...
2
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0answers
87 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 ...
0
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1answer
55 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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0answers
52 views

Exporting .bullet file from Blender Render

I'm trying to export my blender render bullet world to a .bullet file. Unfortunately, it seems like when I bring my bullet world to the game engine it drops the bullet info. Is there a way to export ...
2
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1answer
64 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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2answers
208 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
70 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
150 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 ...
2
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2answers
188 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
64 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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0answers
129 views

Bullet Physics Raytrace Picking

I'm having trouble picking using bullet's raytrace code Here's what I have so far for creating the actual Ray float top = 1.f; float bottom = -1.f; float nearPlane = 1.f; float tanFov = (top - ...
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2answers
565 views

Bullet physics in python and pygame

I am programming a 2D sidescroller in python and pygame and am having trouble making a bullet go farther than just farther than the player. The bullet travels straight to the ground after i fire it. ...
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1answer
83 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) ...
8
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1answer
390 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 ...
0
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1answer
319 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 ...
2
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1answer
317 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
38 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 ...
5
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1answer
668 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 ...
6
votes
1answer
1k views

How can I get my meshes to work with Bullet Physics?

The problem is that I'm trying to use my meshes with Bullet Physics for the collision part of my game. When I attempted doing this method with my GLM(model loading library by nate robins) model, I ...
0
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1answer
2k views

Best 3D Physics Engine to use with Ogre [closed]

I am looking for a good physics engine to use with an Ogre game I'm writing. I would prefer for it to be free, open source, mature, simple to use, easy to learn, and flexible. I'm currently thinking ...
3
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1answer
6k views

How do I integrate bullet physics into my game?

I downloaded the release file found here, but I'm just not sure where to start. In my game I have a number of oblongs and a sphere, I want all of these to collide with one another. (They all have ...
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1answer
358 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
383 views

Shoot Bullet Towards Touch Position : Unity3D

I have one object shooting in x-y plane..,x means horizontal and y means vertical direction.. My bullet is capsule game object with rigidbody component. Now Whenever i touch on the screen , i want ...
0
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1answer
438 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 ...
1
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0answers
260 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 ...
2
votes
1answer
42 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 ...
3
votes
1answer
908 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 ...
3
votes
1answer
373 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 ...
4
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1answer
558 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 ...
0
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2answers
708 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 ...
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2answers
305 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: ...
0
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2answers
403 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 ...
1
vote
2answers
402 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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2answers
802 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 ...
2
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0answers
138 views

Bullet btGeneric6DofConstraint and btGeneric6DofSpringConstraint constructor arguments

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 ...
2
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1answer
408 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 ...