# How do I get the 3d coordinates of my model Instance? [LibGDX]

I want to get the 3d coordinates (as a Vector3) from my model Instances. with the following code I can only get the original coordinates, but in the render method, my model is rotating around the Y-axis (and moving at the same time) and I want to get its coordinates each frame. I'm using a little class created by @Xoppa :

public static class GameObject extends ModelInstance {
public Vector3 center = new Vector3();
public Vector3 dimensions = new Vector3();

public BoundingBox bounds = new BoundingBox();

public GameObject (Model model, String rootNode, boolean mergeTransform) {
super(model, rootNode, mergeTransform);
calculateBoundingBox(bounds);
bounds.getCenter(center);
bounds.getDimensions(dimensions);
}
}


and here's my code:

public void render(float delta) {
super.render(delta);
}

Gdx.gl.glViewport(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);

batch.begin();
backgroundSprite.draw(batch);
batch.end();

for(GameObject instance : instances){
instance.transform.rotate(new Vector3(0, 1, 0), 0.5f);
float x = instance.bounds.getCenterX();
float y = instance.bounds.getCenterY();
float z = instance.bounds.getCenterZ();
System.out.println(x+" "+y+" "+z);
if(isVisible(cam, instance)){
modelBatch.begin(cam);
modelBatch.render(instance, environment);
modelBatch.end();
}
}
}


Try something like:

Vector3 position;
position = modelInstance.transform.getTranslation(new Vector3());


This gets the position and stores it in the position vector.

Sometimes you might have to transform the transform with the view and projection matrix to get the correct result.

/* Make sure that you use a new Matrix4, otherwise you will
change the models transform, which we don't want to do. */
Matrix4 modelTransform = new Matrix4();
modelTransform.set(modelInstance.transform);
/* Multiply the transform with the combined matrix of the camera. */
modelTransform.mul(camera.combined);
/* Extract the position as usual. */
Vector3 position;
position = modelTransform.getTranslation(new Vector3());


This gets the position and stores it in the position vector and the transform and stores it in the modelTransform matrix. You should probably re-use this vector and matrix every time you get the position instead of creating new ones.