Solidworks Animator Problem

I'm a bit stuck...

How would I go about animating a balloon expanding in Solidworks - is
there a way of making say an assembly of lots of different size
balloons (one showing at a time) and morphing between the sizes?
(without it looking like one part fading in and out of transparency).

Thanks.

 

You can animate a sketch to achieve this

I used to use that technique for rubber membranes and inflating seals.

 

What do you mean animate a sketch? Change the skecth which alters the
model? I want to animate the model - a series of render frames.

 

Yes you can drive the model sketch as you change its shape it will
update the model and when you render it it will inflate like a balloon