We have decided not to make our model of Optimus Prime transform into a truck as this would necessitate a reduction in the quality and detail of our final model.
Our Optimus Prime is intended to be a very highly detailed museum-quality replica. The additional parts that would be required to enable a transformation at this scale would result in a model that would be quite dissimilar to the original. The electronic components that will evoke the nostalgia that we enjoy from the G1 series of The Transformers would not be possible in a transforming model.
Our final model will weigh over 11kg (24lbs), be fully poseable, and able to stand without the aid of supports which are important features of an Optimus Prime model that prevent transformation.