How to Bevel on the inside of a corner?

Having this object here, I would like to make some inner round edges just like Bevel (ctrl + b) does for a corner on the outside but this time I want it on the inside.

Please note that I want the rounding done on the outer of the inner corners (red mark) not the inside of the inner corner (green mark)

I did try to slice the corner area and then use Bevel on that inner edge but that doesn’t seem to work either. See the video below:

To bevel you need to select an edge or an edge loop and press Ctrl B, what does it give?

This is what happens:

I can bevel but only from the inside corner to the inside of the box and I want in the opposite direction as described in the initial image, I want the bevel to be where the red marks are.

do you have an example of what you want to achieve, or a drawing? It’s not clear to me

Hi James. Is this what you are looking to do.

If so, I basically took a plane then shift-ctrl b for the 4 vertices that I wanted round. Then I counted how many vertices for each corner so that I could create the same number of vertices on another plane. So when I bridge edges, they match nicely. The two blue options have a bevel modifier applied to them to keep that crisp edge and also shaded smooth. Of course, you may have to play around with your vertices to get the results you want. Good luck and hope this gives you some ideas. File attached.roundedinsidecorner.blend (1000.3 KB)

Bevel or chamfer in the original meaning does cut of a sharp edge for example on a wood beam… Doing this again and again on the newly formed edges does some rounding effect… in 3D modelling there is also a inverse bevel possible (inner edges) putting material on the edges… doeing this in a symetrical way needs symetrical planes one both side sof the edges… (so your exmaple gets this unsymetrical curve) .So if you wanna do something like simulating milling or mortise on the given shape (inner rmeasures) you have to copy the inner geometry for reference, do the inner beveling and resize it so the inner radius fits into the ref… or model the inner geometry to fit on the wanted positions in the first place… (maybe make a sketch plan before)…