Modeling flat surface shapes on a cylinder

Question

I started making one of these fun little posing dolls for a project, figuring that it would be an ultra easy task and a little bit of fun with rigging. I've run into a problem with the basic modeling. If you take a look at the pelvis piece, you'll see it is essentially a cylinder with a flat area on the front. Creating this flat area has proven to be a challenge, or I'm just missing the very obvious. I tried to draw the arc using the verticies and then scale all evenly on that axis, and it sort of works but looks very sloppy. How would you go about creating this little puzzle? Here is a picture of the area in question... I know I'm probably missing something obvious.

https://gyazo.com/35b7a85d7a7f217eb6fbdeb1281eb9a7

Answer 1

A possible solution is to use a boolean modifier

Starting with your round shape:

Create a cube and rotate it in the angle you need for the flat surface:

Then place the cube where you need the cut:

On the pelvis object add a boolean modifier, usnig difference mode ans selecting the cube as object:

To view the results just move the cube to a different layer or make it invisible (H) and unrenderable (CtrlH

The advantage of this method is that you can still adjust the angle and placement by moving the cube, and when you are done you can apply the modifier.

The disadvantage is that you'll end up with some n-gons

Other way to do this is with the knife tool, in wireframe mode choose a side view for the cut and press K along with the Zkey to greate a straight cut:

Then you'll have to do some cleanup to get rid of unwanted vertices.