Real-Time Physics Simulation Forum

This looks awesome!

Erwin: Is it straightforward to integrate one of these "soft constraint" springs into btMultiBody ? Or can we already simulate mobilizer springs (springs along the DoF permitted by the joint) with the current motor constraint for btMultiBody ?

Based on the quoted code from "btGeneric6DofSpringConstraint.cpp" in the original post, the 6Dof spring constraint in Bullet is just a spring force element. It's not soft constraint which is still implicit and still need a solver like the QuickStep to solve the equations. A force element i...

This is not physics simulation. Since you prescribed the velocities of your rigid body parts what you did is just forward kinematic at velocity level. You're better off key framing such animation directly in Blender with a standard Rig setup. For dynamics simulation of Ragdoll you'd want to apply fo...

On a secondary note I will probably avoid using synchronizeMotionStates since it's invoked every sub-step. Depending on if the rendering update is synchronous to the physics step and the frequency, a per sub-step motion state sync could be a waste of cpu cycles.

Regarding to "lock" a DOF of a 6Dof joint shouldn't we actually add a constraint to remove that DOF from the joint instead of setting joint limits to 0/0? Joint limits only make sense if the allowed movement range is none zero. Otherwise we are stressing the system by putting on additional...

btDiscreteDynamicsWorld::synchronizeMotionStates() is responsible to synchronize the transforms of rigid bodies in the discrete dynamic world with the application. However there is no synchronizeMotionStates() implemented for btMultiBodyDynamicsWorld(). Is there an alternative way to synchronize th...

btDiscreteDynamicsWorld::synchronizeMotionStates() is responsible to synchronize the transforms of rigid bodies in the discrete dynamic world with the application. However there is no synchronizeMotionStates() implemented for btMultiBodyDynamicsWorld(). Is there an alternative way to synchronize the...

I'm not an expert on this. Intuitively the sequential impulse solver may not give you the accurate measurement of the interaction force between blocks. Reason is that it's an iterative solver that generates the necessary impulses on each body to satisfy the contact constraints. Depending on the stac...

If you just use a spring force to correct position error between each pair of bodies it will work assuming g: 1. You tune the PD constants of the spring nicely and don't attempt to correct any error "instantly" 2. Lower your simulation step size to small enough to pair with your body's mas...

Let's say we have the angular velocity of a rigid body in its local coordinate frame in the form of (Rx, Ry, Rz) how to map it to a different coordinate frame (the world CF or another CF on a different location of the object? I assume you cannot simply multiply the transform matrix of the CF. Simila...

The INSTALL problem is because of lack of administrative privilege. It can be worked around by copy/paste the install cmake command line to a command prompt with administrative privilege. With that the RBDL header files can be installed to "C:\Program Files (x86)\RBDL\include\rbdl". Howeve...

The "ALL_BUILD" project builds fine now! Thanks! The "INSTALL" project still has some build errors, not sure if it's intended for windows platform: ------ Error 1 error MSB3073: The command "setlocal "C:\Program Files (x86)\CMake 2.8\bin\cmake.exe" -DBUILD_TYPE=Deb...

This is awesome! I tried to compile the source with Visual Studio 10 on Windows 7 and got the following error: 1. Cmake command I used to generate rbdl.sln mkdir build cd build cmake -D CMAKE_BUILD_TYPE=Release ..\ 2. Visual Studio 2010 build error: Error 1 error C2678: binary '==' : no operator fou...