I would like to create a segmented look of my spaceship with hatches and paneled armor segments. I have the outline of it already modeled, but I am lost how to create the segments. I don't want to model them, I would much rather paint them on with a texture.
UV unwrapping gives me a texture, but painting the UV externally makes it very difficult to figure out what the final distortion will be.
How can I paint on nice, straight geometric lines directly onto the model?
Not that this is preferable, but at least you can make something happen with bump if you want.
First we set up our object to paint, and set up a 4k image texture to the Bump slot of our object, checking the box to use Float.
Next we turn on Face select masking so that we can make a selection while in texture paint.
Next we use View>Align to View>Top to get our object view to the top of the selection so we can make as straight a curve as possible.
After setting stroke method to 'Curve', use ctrl-click to set points along the features you want from view, making sure to follow the curve of the underlying wireframe as reference.
Turn off Face select masking, and press the Return key to stroke the curve - I use a small brush radius here, but be careful not to zoom in and out because that will mean a lot of variation in stroke width.
Lastly, you can preview the result after switching to Object mode, and then determine if you need to invert the color of your texture to get the opposite direction. White is up, Black is down, and grey is middle.
A new way occurred to me - you can draw on the surface with Grease Pencil strokes and then convert them to disconnected curves, and then give them some depth in the curves panel - then bake the main object with AO to get a black and white mask (sorta) to use for lines - also on the left, the curves actually look cool too.
