Removing remnants of an extrusion operation

[pashman]

Folks, another newbie question. So I have a block, and I'm trying to create a foot-shaped indentation into it. I select a bunch of faces and do an extrusion operation to sink those faces into the shape. Sometimes that does what I want, but then other times it pushes a set of edges below the shape, which I don't want. It's like the cuts lose their resolution. I can grab both faces and dissolve it, but then it leaves a hole in my model. Attached is a case in point. What's the best way to take away from a shape in the way I'm trying?

[VladD]

to correct this particular mesh easily, from the current selection of faces, you could do this in the context menu:
(Left click) Scale Axis, then RIGHT click on 'Y' (to pick a point from), and initiate the scale by picking the topmost point of your initial selection. Then hit the TAB key and enter 0%. (or we could also use the Flatten command)
Finally, select your whole object and do a cleanup command.
Now, it's important to understand why it works, in this specific mesh: Since the previous scale trick perfectly stacked the extra edges the cleanup op' got rid of them easily.

Sometimes though, I'm betting that this won't be so easy. I guess it depends of how you started your modeling and I'm not sure how you got those "extra faces" from simple extrusions. In anycase, to carve out details, from experience I found that it is sometimes easier to do things in reverse: start from the recessed parts then extrude outward them to build up the shape.

In some cases, rather than extrude, you might also experiment with the Inset command. It is a very versatile tool (which can be used as a kind of "power extrude", with more options). As usual, be sure to check its many options, first when overing your mouse over its name in the context menu, since left, middle or right click will initiate a slightly different version of the tool. Then keep an eye on the info bar at the bottom, for further options. Including on the right part of it (for the Average/Along edge toggle keys). For what (I think that) you're trying to achieve, I would say that the Right click version of Inset is your best substitute for shaping up smooth feet imprints.

[pashman]

I think I got it. You need to be careful in an extrusion operation to not grab sides of objects, but rather just their top faces. Then, if you need to get rid of the sides that are left, it's very easy to not clear the previous selected face as you are selected the side faces to delete, and end up deleting more than you wanted. I think that's what happened to me. I have to believe there is a better way to do this, but I got done what I needed to.