How to cut a part of a curved section

[rwalker43]

I am trying to create a vent cover for a project box.  I created a 10 mm cylinder and extruded it such that it's center is 8 mm deep and the walls are 2mm thick.  I want to cut out a third of the surrounding wall, but have been unable to make much headway.  Needless to say, I am a noob, so any help would be appreciated!

[hamid.sh.]

Is this what you want? I did it with a extrude cut starting from inside bottom up to the top surface.

If not, please export (*.f3d) and share your file here or at least a picture so forum users can help.

[rwalker43]

Thanks for your reply!  Yes, that is what I'm trying to do, but I don't understand how to limit the extrude to just that section!  How do I define the area to be extruded!

[hamid.sh. · Accepted solution]

I added two lines in the base sketch, and in the extrdue I used that area to cut. Note that I could have added one additional sketch on cylinder's bottom and define the area in this new sketch, but for this I needed to have edges of the cylinder (which I could get using Project tool in sketch), so I just did it in the first sketch that I already had cylinder edge.

If you right click on the second extrude and select Edit Feature you can see the profile that I used. Also check how I used From Object and To Object to start cut extrude from internal bottom to the top surface. 

[TheCADWhisperer · Accepted solution]

@rwalker43 

See alternative technique Attached.

[rwalker43 · Accepted solution]

I was able to use your drawing to create the object that I wanted, however, the other method cited turned out to be better for my purpose!  Thanks again!  What I learned will help in the future, I'm sure!

[rwalker43]

I was able to create exactly the object that I wanted.  Both solutions worked, but I was able to add other elements more easily using the method that you suggested!  I've attached the finished product!  Thanks for your help!