Expand a 2D-Mesh in Orthogonal direction as seen from each individual Edge

[Rabbit]

Imagine the letter S with some Thickness and in 3D (Picture one).

I now want to expand the bottom 2D-Surface of that letter orthogonally along the XY-Plane, so that when viewed from above (Picture 2) the bottom surface is thicker and scaled out orthogonally and evenly to each individual edge of the bottom Surface.

I need a procedural way to do this for many different letters’ bottom Surface. I imagine something like the insect Faces “I” command but outwards instead of inwards. Could probably be done with geometry nodes but I am not proficient enough in those.

background information: It is a 3D-print for a cast mould. For better stability of the cast iron, the bottom of the Letters needs to be thicker.

[Hadriscus]

You want what the shrink/fatten transform operator does, essentially ? moving every vertex along its normal, but constrained to the XY plane ?

If I understand correctly, you could

1. isolate the desired vertices (by their Z position for instance)
2. use the normal input node to move those vertices, use a vector scale node to control the effect
3. keep only the X and Y components of the transform, type 0 into Z, and plug the result into the offset input of the set position node

Something like this :