How can I modeling these case more efficiently?

I tried modeling as shown above. I separated the edge and moved the 3d cursor and origin. I also used multiple snaps and joined the edges back into their original objects to create faces. I got the results I wanted, but I felt my process was a bit complicated. The GIF below is a summary of my process.

The extrude region vertex normals (Alt + E) function is close to the operation I want, but it does not produce a flat surface if it carves out the interior.
Probably there seems to be a modeling technique I’m missing. If you have ideas for a faster process, please let me know.

And i attach the blend file for the convenience of the respondent who will show the example. Thanks for your attention.
Modeling Question.blend (88.3 KB)

Here’s a workflow with fewer steps.

  1. Delete faces not co-planar with the surface.
  2. Inset thickness value. Uncheck the “boundary” option.
  3. Inset depth value.
  4. Loop select top and face fill.
  5. Loop select bottom and face fill.


Oh … I didn’t know that the inset feature had a depth option. This is a very useful and fast.