how to create shell in this model?

this is the tutorial example in solidworks. Even though i followed the instructions I am unable to create shell with the thickness of 3 mm . can anyone help with this?

Accepted answer

Robert's got the right answer. I'm just adding an image to show the difference between your model and the tutorial.

Your model has a centerline running it's length, this is causing the Thin Feature Robert mentions.
The tutorial has a line (not a centerline). That allows the sketch to be "closed", and allows the Revolve feature to make a solid.


1 Other answer

The first solid feature in your model, Revolve-Thin1, shouldn't be a 'thin' feature.

Due to the 'thin' feature, your model is already sort of shelled, that is to say, it is hollow, and this hollowness is not allowing the shell command to work.