CollisionShapes and Nodes in jbullet-jme

Troubleshooting physics
1

Hi all,



I've a problem with CollisionShapes. When I want to add a 3d model to my scene and surround it with a CollisionShape it seems always like the middle of the CollisionShape is on the "ground" of the Node so every model stands a piece abouve the Ground and not on the Ground.



I searched the forum but doesn't find a solution so has anybody an idea?



My Code for an example:


Node model =null;
        try {
            model = (Node) BinaryImporter.getInstance().load(new File(System.getProperty("user.dir")+"/models    /run/run.jbin"));
        } catch (IOException ex) {
            Logger.getLogger(test.class.getName()).log(Level.SEVERE, null, ex);
        }
        model.setLocalScale(0.05f);
        model.setModelBound(new BoundingSphere());
        model.updateModelBound();
        model.updateWorldBound();
      
        model.getController(0).setActive(false);
        model.updateGeometricState(0, true);

        SphereCollisionShape shape = new SphereCollisionShape(model);


        character=new PhysicsCharacterNode(model, shape, .1f);
        character.setLocalTranslation(0,3,0);
        state.getRootNode().attachChild(character);
        character.updateRenderState();
        pSpace.add(character);

2

After setting the collisionshape, call attachDebugShape(assetManager) on the node to see the collisionshape, then the problem should become apparent.

Cheers,

Normen

3

wow, that was a quick reply, thanks!



could it be that the function is from jme3? I'm using jme2 and can't find the function attachDebugShape(assetManager)    :smiley:

4
Bastard said:

wow, that was a quick reply, thanks!

could it be that the function is from jme3? I'm using jme2 and can't find the function attachDebugShape(assetManager)     :D

Yes it is, the debug view works differently in jme2. Theres a test example how to set it up.
5

ok, I get it. Thanks very much, it works with "normal" PhysicsNodes but do you have an idea what I can do for PhysicsCharacterNode? Cause this Node needs a SphereCollisionShape!

6
Bastard said:

ok, I get it. Thanks very much, it works with "normal" PhysicsNodes but do you have an idea what I can do for PhysicsCharacterNode? Cause this Node needs a SphereCollisionShape!

Huh? I dont understand? Yes, characters in the jme2 version of the library can only have sphere collision shapes.
7

Ok, maybe I should more explain. To get the PhysicsNode on the ground I've used a CompoundCollisionShape because I can position this Shape. But I can't use the CompoundCollisionShape for a PhysicsCharacterNode and so here my question: Is there another solution for this?

8
Bastard said:

Ok, maybe I should more explain. To get the PhysicsNode on the ground I've used a CompoundCollisionShape because I can position this Shape. But I can't use the CompoundCollisionShape for a PhysicsCharacterNode and so here my question: Is there another solution for this?

Move the child shape (model) so it is in the center of the sphere?
9

Thanks normen,



I've tried it always with translate the model before creating the CollisionShape, now after the creation it works.



For everybody who has the same problem:


        SphereCollisionShape shape = new SphereCollisionShape(model);
        model.setLocalTranslation(0, shape.getCShape().getMargin()*-1, 0);

10

Please dont use the getCShape() method, it will only return a long when the physics go native.

11

Is there any other posibillity to get the size or extent of the CollisionShape to translate the model?  :?

12
Bastard said:

Is there any other posibillity to get the size or extent of the CollisionShape to translate the model?  :?

No, but you know your values now :P I guess I should add that method to CollisionShape.
Cheers,
Normen
13

damn, ok thanks normen

14
Bastard said:

damn, ok thanks normen

Added to svn version