CollisionShapeFactory weirdness

Troubleshooting physics
1

Hello, I’m trying to create a pretty simple world (i’m still a programming nube!), basically taking the HelloCollision tutorial and switching in my own mesh (think a box with the top cut off). However after turning on the collision debug, I find that there is a proper mesh in place, but also a smaller second mesh, and a bunch of random lines.

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Can the CollisionShapeFactory not handle concave shapes? Or am I doing somthing wrong?



Thanks!

2

Alpha-4? Then you can just ignore the lines, its a debug view issue. Should be fixed in nightly since quite a while.

3

Thanks for the reply! I do have one other problem, I have a cylinder in the world (using the CapsuleCollisionShape, cause I couldn’t figure out what halfextents are for the CylinderCollisionShape). However the collision mesh and the Spatial are in different locations. setLocalTransform and setPysicsLocation doesn’t seem to move it. Is there a way to get these two to line up?







Thanks again.

4

Probably you generate the collisionshape while the spatial has a localTranslation. This doesn’t happen in nightly either. In alpha-4 simply create the collisionshape with a non-attached and null-translation object.

5

Hmm, I can’t even seem to get the collision mesh to appear in a new file. I copied the HelloCollision tutorial, and created a second character (called baton) and turned on the debug. However the collision mesh doesn’t seem to have been created.

pre type="php"
public class HelloCollision extends SimpleApplication


  implements ActionListener {


  private Spatial sceneModel;


  private Material white;


  private BulletAppState bulletAppState;


  private RigidBodyControl landscape;


  private CharacterControl player;


  private CharacterControl baton;


  private Vector3f walkDirection = new Vector3f();


  private boolean left = false, right = false, up = false, down = false;


  public static void main(String[] args) {


    HelloCollision app = new HelloCollision();


    app.start();


  }


  public void simpleInitApp() {





    bulletAppState = new BulletAppState();


    stateManager.attach(bulletAppState);


    





    white = new Material(assetManager, “Common/MatDefs/Light/Lighting.j3md”);


        white.setTexture(“DiffuseMap”,


                assetManager.loadTexture(“Textures/white.png”));


        white.setFloat(“Shininess”, 5f);





    viewPort.setBackgroundColor(new ColorRGBA(0.7f,0.8f,1f,1f));


    flyCam.setMoveSpeed(100);


    setUpKeys();


    setUpLight();





    sceneModel = assetManager.loadModel(“Models/landscape.j3o”);


    sceneModel.setLocalScale(2f);





    CollisionShape sceneShape =


      CollisionShapeFactory.createMeshShape((Node) sceneModel);


    landscape = new RigidBodyControl(sceneShape, 0);


    sceneModel.addControl(landscape);


    sceneModel.setMaterial(white);


    


    CapsuleCollisionShape batonShape = new CapsuleCollisionShape(1.5f, 6f, 1);


    baton = new CharacterControl(batonShape, 0.05f);


    baton.setGravity(0);


    baton.setPhysicsLocation(new Vector3f(0, 0, 0));





    CapsuleCollisionShape capsuleShape = new CapsuleCollisionShape(1.5f, 6f, 1);


    player = new CharacterControl(capsuleShape, 0.05f);


    player.setGravity(0);


    player.setPhysicsLocation(new Vector3f(0, 10, -20));





    rootNode.attachChild(sceneModel);


    bulletAppState.getPhysicsSpace().add(landscape);


    bulletAppState.getPhysicsSpace().add(player);


    bulletAppState.getPhysicsSpace().add(baton);


    bulletAppState.getPhysicsSpace().enableDebug(assetManager);


  }
/pre



What am I missing?

6

Spatials. You just have controls hanging in thin air basically.

7

Thanks for your patience, I found the problem. The object wasn’t centered at 0,0,0 in Maya when I made it. I had assumed that didn’t matter after exporting it with OgreMax. At least I have a little hair left that I haven’t torn out!