How to perform sketch and action like below

artur_maczynski936

https://cad.onshape.com/documents/a6c6c5963c8393a7e1aaa5b5/w/312d9d8a453301a73ff68484/e/9dd5bc8710897bce43768222

Sketch on line 
which is on the surface of loft face.
to evenly sketch and extrude shape on this line
How ?

robert_scott_jr_

Hello Artur. I'm not able to understand what you are trying to achieve based on your description. Can you take a screen shot with added annotations?

STEG

I don't understand either what you're trying to do.

First recommendation I can give after looking at your document: get rid of all the exclamation marks in the feature tree!

glen_dewsbury

I'm with Robert & Steg. Way too many empty sketches and planes left behind. This only helps to confuse. Not so much need for all the planes, sketches can be drawn on implicit mates based on existing geometry hat will self adjust when changes are made up stream. Not sure what all the splits are about!
A trip through the learning center will help to clarify a number of things. Especially OS Fundamentals and Cad Basics.
https://learn.onshape.com/catalog?labels=%5B%22Self-Paced%20Courses%22%5D&values=%5B%22All%22%5D
I had some time this morning so I made an other part studio as a sample of my 'interpretation' of what you're trying to accomplish. Hope it provides some useful ideas that you can use. Note the reduction in features from 60 something down to 25. Could've reduced further.
https://cad.onshape.com/documents/628236187e79cb8f3d2effc0/w/0f40fafa08b6c7627aec313f/e/d5da09e49f8dac1a9ce7d281

I like the surface text FS. I'll have to put that on my list.