How to render a model in a ViewPort?

I would like to render a model in my viewport but the code I currently have isn’t working. Sorry if this question is somwhere already or the answer on the wiki, but I haven’t been able to find it. Sorry for the sloppy code!
/** Must add a light to make the lit object visible! */
DirectionalLight sun = new DirectionalLight();
sun.setDirection(new Vector3f(1, 0, -2).normalizeLocal());

	Spatial gun = assetManager.loadModel("Models/STG44/stg44.blend");

// gun.scale(0.05f, 0.05f, 0.05f);
// gun.rotate(0.0f, -3.0f, 0.0f);
gun.setLocalTranslation(1, 3, 1);

    Camera cam2 = cam.clone();
    cam2.setViewPort(5f, 1f, 0f, 0.5f);
    cam2.setLocation(new Vector3f(-0.10947256f, 1.5760219f, 4.81758f));
    cam2.setRotation(new Quaternion(0.0010108891f, 0.99857414f, -0.04928594f, 0.020481428f));
    view2 = renderManager.createMainView("Bottom Right", cam2);
    view2.setClearFlags(true, true, true);

I can’t see where to edit my post, but the behavior is just a black screen.

may not be THE issue but im pretty sure this line is not correct:

cam2.setViewPort(5f, 1f, 0f, 0.5f); perhaps you meant .5f for the first parameter

other than that your issue could be the camera not pointing at anything interesting. everything else looks correct.