Can shapes with rounded corners be extruded with even thickness?

Question

What I want to achieve is to extrude and scale the inner shape to the outer one like this:

The center of the shape seems to be attracted by the roundings, I tried to use bounding box center but this is still not what I want. Is there an easier solution then separated / extrude / join the parts?

Answer 1

There is a way to use the inset tool like an extrude for a flat shape.

1. Select the loop of vertices you want to extrude inwards.
2. Fill in the area with a face F
3. Inset the selected area I
4. Delete the face

You do get small size variations in the new edge lengths around the curve compared to the straight sides but the amount is very small.

This only works gong inwards so you will want to scale your shape up to the larger size and then inset to the smaller size. With a bit of effort you can create a bounding box around your shape, fill it in with faces and press O while insetting to change to outset to enlarge your shape. Note in this example that the corners overlap and need cleaning.

Answer 2

There is a script that is specifically tailored to this task, it's called "offset edges":

http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Modeling/offset_edges

It has many options that are very helpful, for example vertices at the ends of the offset edge loops can be aligned with the adjacent visible edges etc. You can use negative values of "Width" to offset inwards.

Here is how to use it:

Answer 3

Shapes with rounded edges can be extruded, it is not impossible but by extruding one face at a time, then the extruded portion will create a mesh collision or an unnecessary space between extrusions. I suggest that you click all the desired face that you want to extrude and, extrude them in the direction that you want.