Using Pressure with Kangaroo to inflate.

Hi, I'm pretty new to Grasshopper, especially kangaroo, so I apologise if this is a pretty elementary post.

I’m trying to create a model that inflates a mesh, using pressure. I’ve been playing around but I know I’m not doing it right as the mesh is not changing when changing the pressure. I want to be able to really increase the pressure so I get a big expansion, whilst keeping the anchor points at the base so the expansion inflates upwards and outwards.   

Eventually I want to make a model that inflates a folded object so any advice on that would be a massive help.

Thanks for any help in advance,

Alex