Search found 27 matches

by Silverlan
Fri Oct 27, 2017 4:55 pm
Forum: General Bullet Physics Support and Feedback
Topic: Kinematic Character Controller - Inconsistent Jumping
Replies: 2
Views: 1280

Re: Kinematic Character Controller - Inconsistent Jumping

Where do you call that code? Before the world->stepSimulation( ) or in code that is executed every substep? If the latter then it is possible for your world to make two substeps in a single step (depending on how you setup stepping, but I assume you do something sane and normal) which might cause y...
by Silverlan
Sun Oct 15, 2017 2:03 pm
Forum: General Bullet Physics Support and Feedback
Topic: Kinematic Character Controller - Inconsistent Jumping
Replies: 2
Views: 1280

Kinematic Character Controller - Inconsistent Jumping

I'm using a btKinematicCharacterController with a capsule shape for my player character. Everything works smoothly, however when I try to implement jumping by adding an upwards force, the result is very inconsistent: https://youtu.be/e1MsiUosjDk Sometimes the character is jumping higher, sometimes l...
by Silverlan
Mon Sep 25, 2017 9:11 pm
Forum: General Bullet Physics Support and Feedback
Topic: Soft-body physics objects don't keep shape after collision?
Replies: 0
Views: 1131

Soft-body physics objects don't keep shape after collision?

After many struggles I finally managed to get soft-body physics working, however when the soft-body object collides with something, it gets 'dented' and does not go back to its original shape: https://youtu.be/Y5JQYLgYQb8 I'd like to have the same behavior as shown for the ball in this video: https:...
by Silverlan
Tue Aug 22, 2017 9:03 am
Forum: General Bullet Physics Support and Feedback
Topic: Edge collision problems after editing btBvhTriangleMeshShape
Replies: 0
Views: 862

Edge collision problems after editing btBvhTriangleMeshShape

I want to change the vertex positions of a btBvhTriangleMeshShape , but after doing so I get a lot of collision problems near triangle edges: https://youtu.be/7sW7YdmywHo (Original triangle mesh shown at the beginning of the video works fine. After changing the vertex positions at 00:21,the collisio...
by Silverlan
Thu Aug 17, 2017 8:56 pm
Forum: General Bullet Physics Support and Feedback
Topic: Scaling result of getInvInertiaTensorWorld?
Replies: 4
Views: 1640

Re: Scaling result of getInvInertiaTensorWorld?

Meanwhile: are you sure you want to twist the object around using torque? If you can achieve what you want by adjusting the angular velocity (maybe you can't, I dunno what exactly you're trying to do) then you should consider doing that: it is simpler. I want to simulate a quadcopter and I'm applyi...
by Silverlan
Thu Aug 17, 2017 1:14 pm
Forum: General Bullet Physics Support and Feedback
Topic: Scaling result of getInvInertiaTensorWorld?
Replies: 4
Views: 1640

Re: Scaling result of getInvInertiaTensorWorld?

I think you would be better off to scale the non-inverse inertia values assigned to the btRigidBody and then leave the inverse inertia alone. That wiki page may be incorrect. See this thread . Hm... btRigidBody::getLocalInertia returns a vector3, not matrix. My main goal is to calculate the torque ...
by Silverlan
Wed Aug 16, 2017 8:48 pm
Forum: General Bullet Physics Support and Feedback
Topic: Scaling result of getInvInertiaTensorWorld?
Replies: 4
Views: 1640

Scaling result of getInvInertiaTensorWorld?

My engine uses a different scale than my physics implementation, so I need to scale everything accordingly when giving data to / retrieving data from bullet. That works just fine, but I'm not sure about btRigidBody::getInvInertiaTensorWorld . According to this article all inertias have to be scaled ...
by Silverlan
Sun Apr 23, 2017 4:18 am
Forum: General Bullet Physics Support and Feedback
Topic: Calculate volume for convex shapes?
Replies: 2
Views: 1438

Calculate volume for convex shapes?

I want to implement buoyancy into my program, but I've run into a bit of a problem. I already have all of the algorithms in place, but to calculate an accurate buoyancy force I need to know the total volume of the shape for the collision object in the liquid, as well as the volume of the part of the...
by Silverlan
Fri Mar 31, 2017 9:00 am
Forum: General Bullet Physics Support and Feedback
Topic: [SOLVED] Performance problems with version 2.85 and newer
Replies: 1
Views: 1312

Re: Performance problems with version 2.85 and newer

I've done some further testing and it seems that the problems are also there with version 2.83. I've recorded a video of the problem: https://youtu.be/ojAhcyOo4wg The scene in the video has several rigid bodies, some with convex shapes and some with triangle shapes, as well as a kinematic character ...
by Silverlan
Sat Mar 25, 2017 9:54 pm
Forum: General Bullet Physics Support and Feedback
Topic: [SOLVED] Performance problems with version 2.85 and newer
Replies: 1
Views: 1312

[SOLVED] Performance problems with version 2.85 and newer

Up until recently I've been using bullet 2.82. I wanted to try out the new VR-features, so I decided to upgrade to the latest version (2.86), however after the update I've noticed a massive drop in performance for the physics simulation in my engine (To a point where it's unplayable). I did some tes...
by Silverlan
Wed Dec 28, 2016 3:57 pm
Forum: General Bullet Physics Support and Feedback
Topic: btRigidBody accelerating slower than it should
Replies: 1
Views: 1261

btRigidBody accelerating slower than it should

I have a btRigidBody with a mass of 1.0 and a linear damping of 0.0 . Bullet's default gravity is disabled, and physics are simulated 60 times per second. There is no air resistance or wind, and no forces affecting the body, except for my custom gravity, which is applied every game tick: const btVec...
by Silverlan
Sat Sep 24, 2016 8:24 am
Forum: General Bullet Physics Support and Feedback
Topic: Soft-Body Objects fall apart
Replies: 3
Views: 2229

Re: Soft-Body Objects fall apart

I have noticed that inside your code, generateClusters is set to 64 this will create 64 individual softbody convex clusters for your object. It seems like your object is breaking to its 64 individual collision triangular clusters. It's actually a lot more than 64 pieces, changing the cluster count ...
by Silverlan
Fri Sep 23, 2016 9:45 am
Forum: General Bullet Physics Support and Feedback
Topic: Soft-Body Objects fall apart
Replies: 3
Views: 2229

Soft-Body Objects fall apart

I'm trying to create a simple Soft-Body plane-shape, which works great, except for the collisions: https://youtu.be/PO6sNKpmRfA On contact, the entire thing just falls apart triangle by triangle. It's a nice effect, but not exactly what I'm aiming for... What could be causing that? Here's my code fo...
by Silverlan
Thu Sep 08, 2016 4:28 pm
Forum: General Bullet Physics Support and Feedback
Topic: Vehicle collision issues when moving between meshes
Replies: 0
Views: 1780

Vehicle collision issues when moving between meshes

I've already set up the internal edge utility , which fixes the collision issues on triangle meshes, however that doesn't fix the problem for edges between different meshes: https://youtu.be/AjjBGM01Nl0?t=12s static bool custom_material_combiner_callback(btManifoldPoint &cp,const btCollisionObjectWr...
by Silverlan
Fri Feb 19, 2016 3:34 pm
Forum: General Bullet Physics Support and Feedback
Topic: Various collision problems
Replies: 3
Views: 2229

Re: Various collision problems

My first question is are you using any scaling? I wasn't, but I am now. The player is 72 units high, so I've scaled everything down by a factor of 40 (1/0.025). (Player = 1.8 meters) It did help with stability somewhat. Small objects seem to be less twitchy now and I can't push physics out of the w...