Real-Time Physics Simulation Forum

According to the API reference, torque and torque impulse work in torque units. Torque impulse just gets calculated instantly while torque waits for next integration.

Without knowing the internals of osgconv it's going to be hard finding a solution to that side of the problem, but does seem like the conversion from vertices to triangles isn't being done properly and then propagates through. Got no clue as to why convex decomp would do the second thing though, hav...

If that was the actual model I would have said there's your 50 part problem! :wink: From the looks of it, the internal vertices are being mostly ignored, and new surfaces are in relative proximity where you would expect them if the external direction kept switching. How does the obj file look when d...

Are those steps or just a texture?

Yes this is the case with all realtime engines, and it makes sense. However you manipulate them with forces. Applying the velocity is just the same as setting forces as far as I understand. Only if contact isn't involved. If it is, applying a velocity can produce motion where setting an equivalent ...

Why not just use a vehicle with 6dof joint connecting to a rigid body, all on a changing heightmap? The vehicle would follow the heightmap (waves), and the joint could be made with softish springs (to simulate rocking in waves). All you do after that is render a model boat shape connected to the inf...

Question is, do you actually need it to use less resources or are you just making things more complicated for yourself? If you don't have performance issues, no sense in working yourself up over it just yet. If you do, then perhaps there's other ways to go about it, like filtering out collisions oth...

Well, six months and a revisit to old code gave me new insight! It turns out the culprit is a bunch of btScalar k = info->fps * info->erp; strung throughout the joint calculations. Since the joints are calculated each frame, and energy proportional to fps is added each time the joint is calculated, ...

Angular velocity will be in rad/s, just like most other things dealing with angular velocity. The other two are a bit harder to state because they aren't always exactly equal to the equivalent MKS values (i.e. 1.4Nm/=1.4 torque units) due to m_angularFactor and m_linearFactor variables. Even if thos...

Why not just skip BulletDynamics altogether and just use the parts you need when you need them (like collision detection). Didn't realize a physics engine with updating and integration wasn't a "full" simulation though, I've been using it along with ODE for just that! For a simple simulati...

PD + PI = PID A pure PD as Dr.Shepherd describes only amplifies noise and produces overshot. 1) Fuzzy PD and PI controller is not the same as PD+PI, at least not for most situations. But that's a topic for another discussion, and just was used for a joke (though seems it wasn't as funny as I though...

You don't, you just move it kinematically. Kinematic objects just do what you tell them to, but at the same time are still going to push, drag, or otherwise cause effects in the dynamic objects (think newton's action reaction if you didn't get a reaction)

There is no PD control. There are P, PI and PID controls. And the control must make the controlled system reach the desired position, within an error. There's plenty of PD controllers you can implement in real world applications; they're often used for vehicle suspension systems and other disturban...

What method are you using to join two bodies together? I've had some success (at high frequency) using the joint constraints with the characteristics of an AX-12 servomotor using the built in speed based controller in joint space. That one takes into account desired velocity and maximum torque, so i...

Yup, for that one it's different since the box is already in penetration and will jump up with proper coefficients (at least in bullet!). Dirk Gregorius knows a heck of a ton of things in this engine, if he says it should work with that fix it very likely will. Just meant to say that it's not a real...