Search found 58 matches

by KKlouzal
Mon Dec 06, 2021 5:32 am
Forum: General Bullet Physics Support and Feedback
Topic: Issues with multi-threading and compound shapes
Replies: 1
Views: 272

Re: Issues with multi-threading and compound shapes

I seem to be having this same issue however it's only happening on 1 of my 5 test machines.
by KKlouzal
Fri Nov 26, 2021 3:14 pm
Forum: General Bullet Physics Support and Feedback
Topic: btGeneric6DofConstraint - Weld/Parent
Replies: 6
Views: 417

Re: btGeneric6DofConstraint - Weld/Parent

Never fully rigid I can deal with, considerable divergence and wobbliness however is unacceptable..
There must be some values that can be adjusted?
by KKlouzal
Sat Nov 20, 2021 3:09 pm
Forum: General Bullet Physics Support and Feedback
Topic: btGeneric6DofConstraint - Weld/Parent
Replies: 6
Views: 417

Re: btGeneric6DofConstraint - Weld/Parent

Perhaps I'm going about the 'freeze' incorrectly...Instead of setting mass and inertias to 0, maybe I should apply a constraint to the world with all 6 degrees of freedom locked. EDIT: Yes that is much better, no more 'tornado'. There is still a wave that propagates through the constrained objects, ...
by KKlouzal
Sat Nov 20, 2021 4:12 am
Forum: General Bullet Physics Support and Feedback
Topic: btGeneric6DofConstraint - Weld/Parent
Replies: 6
Views: 417

Re: btGeneric6DofConstraint - Weld/Parent

Was able to dig through the forums and finally find a helpful post. // btVector3 parentAxis(1.f, 0.f, 0.f); btVector3 childAxis(0.f, 0.f, 1.f); btVector3 anchor(0.f, 0.f, 0.f); // btVector3 zAxis = parentAxis.normalize(); btVector3 yAxis = childAxis.normalize(); btVector3 xAxis = yAxis.cross(zAxis);...
by KKlouzal
Fri Nov 19, 2021 4:09 am
Forum: General Bullet Physics Support and Feedback
Topic: btGeneric6DofConstraint - Weld/Parent
Replies: 6
Views: 417

btGeneric6DofConstraint - Weld/Parent

Trying to create a btGeneric6DofConstraint between two rigid bodies. Attempting to restrict movement and rotation of the constraint in all 3 axis. I'm able to get the positioning of the rigid bodies correct, however rotations I'm not sure about... PrimaryNode->_RigidBody->activate(); SecondaryNode->...
by KKlouzal
Thu Nov 18, 2021 11:38 pm
Forum: General Bullet Physics Support and Feedback
Topic: Squishy Physics?
Replies: 10
Views: 552

Re: Squishy Physics?

Okay, I've put the rendering of objects in the correct location and eliminated the 1frame delay between physics update->visual update. The residual 'squish' appears to be gone now. Do you have any comment on these last two issues? Video 1 - Many objects spawn quickly in the same location, at first t...
by KKlouzal
Thu Nov 18, 2021 5:48 am
Forum: General Bullet Physics Support and Feedback
Topic: Squishy Physics?
Replies: 10
Views: 552

Re: Squishy Physics?

I was thinking about this some more and agree it may be a purely visual artifact at this point, might need to look into changing exactly when the object is drawn or something else. Thanks for the info on stepSimulation, i'll look into this in depth a little more tomorrow. Not completely sure what th...
by KKlouzal
Thu Nov 18, 2021 4:53 am
Forum: General Bullet Physics Support and Feedback
Topic: Squishy Physics?
Replies: 10
Views: 552

Re: Squishy Physics?

Not sure if it is related but I also have two more examples of what I would say falls under the category of 'squishy physics'. Video 1 - Many objects spawn quickly in the same location, at first they all push out of each other and fall to the ground then spread out. As more and more objects spawn th...
by KKlouzal
Wed Nov 17, 2021 11:46 pm
Forum: General Bullet Physics Support and Feedback
Topic: Squishy Physics?
Replies: 10
Views: 552

Re: Squishy Physics?

double CurTime = GetTime(); double CurTime_Last = GetTime(); while (game_loop) { CurTime = GetTime(); double DelTime = CurTime - CurTime_Last; CurTime_Last = CurTime; printf("/tTIME %f %f\n", GetFrameTime(), DelTime); _Physics->stepSimulation(DelTime); } I believe my calculation of 'DelTi...
by KKlouzal
Tue Nov 16, 2021 11:06 pm
Forum: General Bullet Physics Support and Feedback
Topic: Squishy Physics?
Replies: 10
Views: 552

Re: Squishy Physics?

I am calling dynamicsWorld->stepSimulation(timeStep); Every frame, and only once per frame, passing in the amount of time that has passed since the last frame. Manipulating the value here does not appear to change the 'squish factor'. Can I turn on drawling bounding boxes with debug drawer? If anyth...
by KKlouzal
Tue Nov 16, 2021 5:32 am
Forum: General Bullet Physics Support and Feedback
Topic: Squishy Physics?
Replies: 10
Views: 552

Squishy Physics?

Can anyone tell me why my physics is squishy?
Maybe CCD or some solver info settings?
https://i.imgur.com/YXGc1gK.mp4
by KKlouzal
Mon Oct 25, 2021 7:12 pm
Forum: General Bullet Physics Support and Feedback
Topic: Collision Shape From FBX SDK Vertices
Replies: 3
Views: 464

Re: Collision Shape From FBX SDK Vertices

Thank you for the reply, yes the objects using btBvhTriangleMeshShape are static objects and anything else is currently using btCompoundShape via convex decomposition. excerpt of static btBvhTriangleMeshShape creation: btScalar Mass(0.0f); bool isDynamic = (Mass != 0.f); btVector3 localInertia(0, 0,...
by KKlouzal
Sat Oct 23, 2021 5:22 pm
Forum: General Bullet Physics Support and Feedback
Topic: 30x perfomance difference between PyBullet and Bullet3
Replies: 1
Views: 566

Re: 30x perfomance difference between PyBullet and Bullet3

While I wont say it isn't possible to speed up computation of PyBullet, I will say it should be expected that it underperforms compared to Bullet3. Python is an abstraction layer atop C/C++ so there will be overhead.
by KKlouzal
Fri Oct 22, 2021 11:36 pm
Forum: General Bullet Physics Support and Feedback
Topic: Collision Shape From FBX SDK Vertices
Replies: 3
Views: 464

Collision Shape From FBX SDK Vertices

I am using extracting vertex information from the FBX SDK to construct a btBvhTriangleMeshShape. Firstly I'm not sure if this is the most appropriate type of collision shape to use and secondly the collision shape appears to be deformed. Objects sometimes only collide with one side of some other obj...
by KKlouzal
Mon Dec 02, 2019 8:58 am
Forum: General Bullet Physics Support and Feedback
Topic: Get Forward, Right, Up Vector From Transformation Matrix
Replies: 1
Views: 1624

Re: Get Forward, Right, Up Vector From Transformation Matrix

It was actually rather simple: void moveForward(const btScalar& Speed) { btTransform Trans = _RigidBody->getWorldTransform(); const btVector3 Forward = Trans(btVector3(1 * Speed, 0, 0)); Trans.setOrigin(Forward); _RigidBody->activate(true); _RigidBody->setWorldTransform(Trans); } void moveBackwa...