How to apply outlines to edges of faces in a mesh?

Question

I have a spaceship model and it currently has no materials. How would I go about applying a black outline to the edges of this model for an "anime look". I've included pictures of it in object and edit mode. I would like my object to look like it does in edit mode if that makes sense.

I've experimented with line art tutorials and either they don't work or they only work for the outside of the object. I would like to be able to apply a black outline to the specific spaceship panels I want.

[![enter image description here][1]][1]

[![enter image description here][2]][2]

Answer 1

Using Cycles (bevel node is Cycles only), you can do the following to obtain a mask:

It compares the angle of the face normal to a normal generated by the bevel node.

The less they are the same, the more the map range output is, as the ranges are inverted, so that it provides a mask for the outlines.

(shade flat or autosmooth the model, shade smooth won't work)

---

To change the colors, you can mix the mask output to what you want, a mix color node (as below) or a mix shader, as you need:

Answer 2

If you want the line to be a mesh you can use a vertex group in combination with this geometry nodes setup:

The shader is to prevent the outline from being shown in reflections and from casting a shadow.