Deconstruct mesh& Construct mesh Problem

Hi everyone,

There are three parts of meshes, and i used the "WbJoin" component to join them into one.

And then, I wanted to separate them again after whatever i did something(like move some points) on the meshes.

I wondered how to improve the algorithm below, because obviously there are excessive vertices when doing "Construct mesh". And if there are a lot of meshes, the Ram in my computer would not be enough:(

Thanks for any help!