UV Unwrapping complex drilled cube I know that UV unwrapping is a black art, and I am just beginning to dabble in it and try and understand it. Most of the time with the things I need to unwrap either a Project From View or Smart Unwrap suffices. However I have come up against one scenario where neither will work, and all my attempts to manually unwrap have failed.

The object is basically a cube (extruded SVG shape consisting of 4 lines) into which (as you may have gathered from my other questions) lots of holes have been cut through it using a boolean modifier.

On fairly simple ones a smart unwrap works adequately, since I only need to texture the top and bottom surfaces. However when it gets more complex that fails, and you end up with a number of islands in a complete mess for one surface.  Manually adding seams around the edge of the model to slice it into 6 segments results in a complete and utter mess. Doing a cube projection ends up in a complete and utter mess.

So I am now trying to add seams around the ends of each and every hole drilled in the cube - however there are hundreds of them and doing it manually will take all week - with no guarantee of success.



Is this the right way to do it? Manually adding seams to the top and bottom edges of every hole drilled through the cube? Is there a faster way of selecting these edges to add seams? (the fastest way I have found so far is to look at it obliquely and do a box select around a hole in vertex mode, then add seam, then move on to the next hole).



I think part of the unwrapping nightmare I am having with this model is the horrible mess the boolean operator has made of the mesh. It seems to have made faces overlapping each other which isn't good. Not sure how I go about fixing that kind of thing. (update: adding enough subdivides to my cube solves that, and now I can use a smart unwrap, so this now isn't a problem as such, but good to know how to deal with this kind of thing in future).
Hit Shift+G in Edit mode while having one of the edges selected that you want to mark as a seam.

This brings up the select similar dialog which offers the possibility to select other elements by similar properties (in your example perhaps edge length)

Another way to speed things up is box selection (B) in edit mode or circle selection (C) in edit mode. If you want to get certain stuff out of the way while selecting hit H to hide elements. Just make sure you unhide them before you unwrap.