[SOLVED] counpound vehicle hull

Troubleshooting physics
1

hello,



i try to convert spatials from a scene file that only contains the rigid parts of a vehicle (boxes)



i want to fetch each part and create a rigid box collision shape to add to a compound one



so i use



s beeing a spatial from a list (i use the descendantMatches() function)

Code:
BoxCollisionShape sShape=(BoxCollisionShape) CollisionShapeFactory.createBoxShape(s); ht300Shape.addChildShape(sShape,new Vector3f());

but the shapes are never added

sShape.getHalfextents() returns a 0,0,0 vector

is it possible to do so, i cant find any example of this

thx
2

Yes it works fine, the CollisionShapeFactory does it all the time. Must be something in your code.

3
@normen said:
Yes it works fine, the CollisionShapeFactory does it all the time. Must be something in your code.


no matter what i do it does not add the shapes, so
now i did this
Code:
CompoundCollisionShape compoundShape = new CompoundCollisionShape(); BoxCollisionShape box = new BoxCollisionShape(new Vector3f(1.2f, 0.5f, 2.4f)); compoundShape.addChildShape(box, new Vector3f(0, 1, 0)); 
    spatial = (Node) assetManager.loadModel("Scenes/Rigid.j3o");
    ArrayList<Spatial> list = findByName(spatial,"-geom-1");
    for(Spatial s:list)
    {
        CollisionShape sShape = CollisionShapeFactory.createMeshShape(s);
        compoundShape.addChildShape(sShape,new Vector3f(0,0,0));
       }

…

private ArrayList<Spatial> findByName(Node root,String name)
{
List<Spatial> list = root.descendantMatches(Spatial.class);
ArrayList<Spatial> list2 = new ArrayList<Spatial>();
for(Spatial s:list)
{
if(s.getName().endsWith(name))
list2.add(s);
}
return list2;
}


it seems the two mesh are processed
_Rigid-geom-1 (Geometry)
_Rigid2-geom-1 (Geometry)

the box is added but not the other meshes
or at least not visible
4

What do you mean by “visible”?

5

are you adding it to both a spatial and the physics space?

6

well the 1st box is visible with a blue outline, not the other objects

i would expect they all appear

7
@wezrule said:
are you adding it to both a spatial and the physics space?


no need for spacial to be added
addChildShape works for the 1st box (the actual code from the tutorial)
8

if i could only get the verticex of a spacial, i could have the dimensions to create the boxes i want



i see there is a getVerticesCount() method for the spacial object

but how can i get the vertex coords ?



why is there a setModelBound but no getModelBound method?

9

Why do you do that manually :? CollisionShapeFactory does exactly the same. Also, are you sure they are not added? I guess the debug view just doesn’t get updated.

10
@normen said:
Why do you do that manually :? CollisionShapeFactory does exactly the same. Also, are you sure they are not added? I guess the debug view just doesn't get updated.


I added a second box and it gets displayed correcly
Code:
CompoundCollisionShape compoundShape = new CompoundCollisionShape(); BoxCollisionShape box = new BoxCollisionShape(new Vector3f(1.2f, 0.5f, 2.4f)); compoundShape.addChildShape(box, new Vector3f(0, 1, 0));

box = new BoxCollisionShape(new Vector3f(1.2f, 0.5f, 2.4f));
compoundShape.addChildShape(box, new Vector3f(0, 2, 0));


i found that

BoundingVolume wb = s.getWorldBound(); so objects are loaded correctly
would return data with Extents set to coerents value

as I trace/debug (into jme code), it does this
Code:
1) BoxCollisionShape sShape=(BoxCollisionShape) CollisionShapeFactory.createBoxShape(s);

public static CollisionShape createBoxShape(Spatial spatial) {
…
return createSingleBoxShape((Geometry) spatial, spatial);
…

private static BoxCollisionShape createSingleBoxShape(Spatial spatial, Spatial parent) {
spatial.setModelBound(new BoundingBox());

    BoxCollisionShape shape = new BoxCollisionShape(
            ((BoundingBox) spatial.getWorldBound()).getExtent(new Vector3f()));
   
   return shape;
}

((BoundingBox) spatial.getWorldBound()).getExtent(new Vector3f()) returns correct extents data

but the extents of the shape objects has extents as (0,0,0)

[edit] the extents were empty in the spatial too
11

Sorry, I don’t understand you. Everything works as it should.

12

in CollisionShapeFactory

Code:
private static BoxCollisionShape createSingleBoxShape(Spatial spatial, Spatial parent) { spatial.setModelBound(new BoundingBox()); //TODO: using world bound here instead of "local world" bound... BoxCollisionShape shape = new BoxCollisionShape( ((BoundingBox) spatial.getWorldBound()).getExtent(new Vector3f())); return shape; }

spatial.setModelBound(new BoundingBox()); will erase(obiously) all extents
spatial.getWorldBound()).getExtent ... returns a 0,0,0 vector

so i changed my code (instead of using the factory function)
Code:
for(Spatial s:list) { BoxCollisionShape sShape = new BoxCollisionShape(((BoundingBox) s.getWorldBound()).getExtent(new Vector3f())); rootNode.attachChild(s); compoundShape.addChildShape(sShape,s.getWorldBound().getCenter()); System.out.println(sShape.getHalfExtents()); }

so far it works as i avoid to call setModelBounds on the spacial
the other shapes appeared

i don't get this, maybe a bug, or i used it in the wrong way

anyway thx for your help