A modular system for isometric pixel blocks
This seems to be just one approach to the problem. To my taste, the way they're drawing the vertical lines is ugly (because of the asymmetry), so it made me curious how notable professional isometric pixel art has solved the problem.I checked two games: Rollercoaster Tycoon 2 and X-COM: UFO Defense. Interestingly, they solve the vertical line problem in the same way as each other, but it's in a different way from the link.In those games, instead of having an explicit line border, the line is implied by a shading difference between the two faces, which eliminates the asymmetry. Additionally, the corners at top, middle, and bottom are 4 pixels wide instead of 2.(This strengthens my conviction in the following rule of thumb: when it comes to art, it's better to study professional work I like than to trust a guide.)