Using 3D sketch to create new part in assembly (SW2016)

Hi everyone,
I'm modeling a tubular frame of three-wheeled vechicle. I have a welded prototype and I've already measured and put all important points in the model and now I would like to add new part to the model which are bent tubes which will fit the rest of parts.
I wanted to use 3D sketch and welded construction module, but is it possible to add a new part directly in assembly using 3D sketch?
When I'm trying to do so the 3D sketch icon is inactive, and I have to chose the plane to start normal 2D sketch.
I've used welded construction module before, but never directly in assembly.
I would be grateful for any advice.
Thank you.

1 Answer

You need to first add the new part with 'insert, component, new part'. Then 'edit component' on the new part and you should be able to now draw 3d sketches that reference the important points in the model.