Intersection between TriMesh and Box

Troubleshooting graphics
1

Hi,



I need to compute the intersection between a TriMesh and a Box. This computation needs to be performed when the Box is visible, but the TriMesh is not. Is such a use case possible at all using the jMonkeyEngine?



Thanks,



Dan

2

Sure, bounding intersection is a math check and does not care about rendering

3

Thanks for the reply! It seems to work, indeed. but not as I expected.

Please see the screenshot below. The colored thing is a TriMesh, the textured thing is a Box. The green line is the collision that the findCollision returns to me. Do you have an idea of what I do wrong?



The following methods are called on both nodes:


      setModelBound(new OrientedBoundingBox());
      updateModelBound();
      CollisionTreeManager.getInstance().updateCollisionTree(node);



The collision code is something like this:


          CollisionResults results = new TriangleCollisionResults();
          results.clear();
          node.calculateCollisions(_inlineBox, results);
          int nr = results.getNumber();
          if (nr > 0) {
            for (int i = 0; i < nr; i++) {
              CollisionData data = results.getCollisionData(i);
              ...
              for (int j = 0; j < data.getTargetTris().size(); j++) {
                int triIndex = data.getTargetTris().get(j);
                _inlineBox.getTriangle(triIndex, tempVertices);
                for (Vector3f tempVertex : tempVertices) {
                  ...
                }
              ...
              }
              Line intLine = new Line("Intersection " + nrInt, vertices.toArray(new Vector3f[0]), normals.toArray(new Vector3f[0]), colors.toArray(new ColorRGBA[0]), textureCoords
                  .toArray(new Vector2f[0]));
              intLine.setSolidColor(new ColorRGBA(0, 1, 0, 1));
              intLine.setLineWidth(5);
              intLine.setAntialiased(true);
              intLine.setMode(Line.CONNECTED);
             ...
    }



http://wush.net/svn/geocraft/geocraft/trunk/wiki/demo/intersection.png

Thanks a lot,

Dan
4

The screenshot:


5

Sorry, my mistake!

I was reusing the tempVertices instance in the call below:



((TriMesh) node).getTriangle(triIndex, tempVertices);



Dan