Any time. It's REALLY easy to turn models invisible. Also it is only invisible in-game. To make models invisible go into the models stuff (like polygons, headers etc) and go into Materials1 and select on of the things. Now make the thing that says ''Type'' towards the right will say a number. Change it to 3 and it will be invisible. Do that to all of them and you are done.
Would this work on Ivysaur's bud for example? I can't seem to get rid of it without problems.