Search found 14 matches

by Xenoprimate
Thu Feb 09, 2017 6:04 pm
Forum: General Bullet Physics Support and Feedback
Topic: Fixing "Hopping" - Rolling Sphere Collision
Replies: 4
Views: 1672

Re: Fixing "Hopping" - Rolling Sphere Collision

Thanks for the reply Danny.

Unfortunately the geometry in the video is one whole piece and is defined as a btBoxShape, not a mesh. Still, interesting to hear that meshes can exhibit that behaviour- I'll keep that in mind.
by Xenoprimate
Thu Feb 09, 2017 11:21 am
Forum: General Bullet Physics Support and Feedback
Topic: Fixing "Hopping" - Rolling Sphere Collision
Replies: 4
Views: 1672

Re: Fixing "Hopping" - Rolling Sphere Collision

It looks possible that the ball intersects the ground between frames and a large vertical force is added to correct this. This is my thinking too- hence trying "split impulse", but to no effect. Also your simulation rate and gravity seem very large, earth gravity is like -10.f and most games run ar...
by Xenoprimate
Wed Feb 08, 2017 8:45 am
Forum: General Bullet Physics Support and Feedback
Topic: Fixing "Hopping" - Rolling Sphere Collision
Replies: 4
Views: 1672

Fixing "Hopping" - Rolling Sphere Collision

Hey guys, I'm having an issue where occasionally while rolling a ball along a surface, the ball "hops"/skips in to the air as though it's 'caught' on something invisible- even though the underlying surface is often a straight flat one. I made a GFYCAT to demonstrate the issue: https://gfycat.com/Gra...
by Xenoprimate
Thu Oct 06, 2016 4:23 am
Forum: General Bullet Physics Support and Feedback
Topic: Two Outstanding Issues
Replies: 7
Views: 2665

Re: Two Outstanding Issues

The first issue looks a bit like you are loosing contact points. What collision margin do you use? You would need to scale this one as well. I think that Bullet also uses a distance threshold where it break old contact points. You would need to check that this tolerance works with your units. After...
by Xenoprimate
Wed Oct 05, 2016 2:37 am
Forum: General Bullet Physics Support and Feedback
Topic: Two Outstanding Issues
Replies: 7
Views: 2665

Re: Two Outstanding Issues

What is the type of your level geometry (in particular, what is the geometry type for your rings)? Each ring is a btCompoundShape constructed of (warped) trapezoidal prisms. Is there a better way? The rest of the geometry is either a compound shape (for complex meshes) or simpler boxes/spheres wher...
by Xenoprimate
Tue Oct 04, 2016 3:13 am
Forum: General Bullet Physics Support and Feedback
Topic: Two Outstanding Issues
Replies: 7
Views: 2665

Re: Two Outstanding Issues

Thanks for the suggestion Xcoder79.

I just tried it and it made no difference (other than the ball feeling more floaty, obviously).

The value of 490.5f comes from 9.81f * 50.0f; 50.0f is the dimension of one metre in my game.
by Xenoprimate
Mon Oct 03, 2016 6:10 am
Forum: General Bullet Physics Support and Feedback
Topic: Two Outstanding Issues
Replies: 7
Views: 2665

Two Outstanding Issues

Hi all, the game I've been working on for the past 2.5 years is nearing completion; but there are two outstanding physics issues that I just can't seem to resolve, and I'd really appreciate anyone's help here in getting them fixed. I'm happy to offer a free copy of the game on Steam to you all also ...
by Xenoprimate
Mon Sep 07, 2015 9:19 am
Forum: General Bullet Physics Support and Feedback
Topic: Always-Active Rigid Body Vibrating at "Rest"
Replies: 3
Views: 1528

Re: Always-Active Rigid Body Vibrating at "Rest"

Thanks for the insight. I'm not sure if that would be suitable, because the ball, at any point, may be collided with by independently-moving objects. In the end, I would be resorting to calling ::activate() on it every frame, before the physics tick. Furthermore it feels like a sticky plaster over t...
by Xenoprimate
Wed Sep 02, 2015 11:04 am
Forum: General Bullet Physics Support and Feedback
Topic: Always-Active Rigid Body Vibrating at "Rest"
Replies: 3
Views: 1528

Always-Active Rigid Body Vibrating at "Rest"

Hi guys, I have a 'ball' ontop of a platform that I can tilt according to user input. Here's a screenshot: ballOnPlatform.png Anyway, the ball has its performance deactivation disabled, because it's the main game entity (e.g. setActivationState(DISABLE_DEACTIVATION); ). However I've noticed that whe...
by Xenoprimate
Fri Aug 07, 2015 9:15 am
Forum: General Bullet Physics Support and Feedback
Topic: Thread Safety in the Bullet API
Replies: 3
Views: 2249

Re: Thread Safety in the Bullet API

Sorry to bump, but I'd really like some further insight on this one! - At the moment I'm coercing all calls through a single "master" thread just to be safe.
by Xenoprimate
Tue Jul 21, 2015 12:29 pm
Forum: General Bullet Physics Support and Feedback
Topic: Concave Meshes
Replies: 1
Views: 759

Concave Meshes

Hello - what is the best way to represent a concave model in my world? After a little preliminary research I've noticed there are basically three options: Decomposing the shape in to multiple convex shapes and representing them using a btCompoundShape Using a btGImpactMeshShape Using a btBvhTriangle...
by Xenoprimate
Tue Jul 07, 2015 12:42 pm
Forum: General Bullet Physics Support and Feedback
Topic: Intransigent Bodies - Still need to be able to set velocity
Replies: 2
Views: 1143

Re: Intransigent Bodies - Still need to be able to set veloc

Thanks for the reply. So I need to set the velocity in order to ensure correct collision behaviour but then handle setting the world transform myself (according to that velocity). Gotcha. Thanks.
by Xenoprimate
Tue Jul 07, 2015 12:44 am
Forum: General Bullet Physics Support and Feedback
Topic: Intransigent Bodies - Still need to be able to set velocity
Replies: 2
Views: 1143

Intransigent Bodies - Still need to be able to set velocity

Hi, I'm making a game involving a ball and some walls - the walls need to be intransigent and unaffected by gravity and each other. So at first thought I made them with zero mass and kinematic type. But it seems impossible to set velocity (linear or angular) on them. I'm not trying to add/apply forc...
by Xenoprimate
Fri Jun 26, 2015 5:02 pm
Forum: General Bullet Physics Support and Feedback
Topic: Thread Safety in the Bullet API
Replies: 3
Views: 2249

Thread Safety in the Bullet API

Hi guys - I couldn't find information on this anywhere: How thread-safe is the bullet API? As an example, could I create a btCollisionShape on one thread, update its local scaling on a second, and then add it to a btDyamicsWorld on a third, before say, removing it from a fourth? (Free threading) Or ...