Hi Mala, I'm sorry I'm not undertanding your question:

> When I trimm the curve in order to make the form like I want, it seems to be cutted.

The Trim command does cut a curve, that's the job that it is meant to do.

Is it that you want to add some points to the curve? If so use Edit > Add pt for that, not Trim.

Is there maybe a 2D vector program that you're familiar with that uses a type of Cut tool for adding points to a curve? If so then that's a little different than MoI, MoI's trim tool is for cutting a curve into pieces, not just for adding points for point editing.

- Michael