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Anatomy of the Thorned Hulk

From Diablo 2 Wiki

A page from the archives, showing the design progress of the Thorned Hulk, from concept art through rendering into the final game appearance.

Every monster starts off with an initial design sketch made by a character artist. The sketch is then used to begin 3-D modeling of the monster. First, a wireframe model is built by manipulating polygons.
Textures are then applied to the faces of the polygons, which make up the monster. The finished model can then be rendered at game resolution, or at a higher resolution for other purposes such as cinematics and press materials.

Archives-act3 14lrg.jpg
Archives-act3 28lrg.jpg
And here we see the finished product, in two screenshots from Act III.