   problem with zoom and unproject
  My first problem here is for zooming.I actually load a model from an object file into the scene. The next thing I have to do is to draw strokes on the scene using mouse dragged event.This stroke has to appear infront of the model. I manged to do so but not sure if its the right way. I then implement rotation and zooming to my model and I have having problems with that.I am able to implement the rotation properly. but when it comes to zooming, it screws up. 1st way I tried was just put push the camera along the z axis towards the model.. then it looks bigger. when I do this, I am not able to see my stroke anymore.2nd way I tried was to translate the model, now that the model is moved away from the origin, when i do roatation, its still rotating about the origin and not about the model.Anyone has a solution to this?My second problem here is for gl.glUnproject.for the argument of this method how should I determine my z value?Also I would like to know why is it my canvas has the size of only like 1?Because when I draw the stroke, I realise the point that I am going through for the x axis is only from minimm of -0.6 to maximum of 0.65 roughly.Thanks in advance for the help.   