These are basic tips for optimizing and improving low-polygon work in the areas of modeling and texturing.
Core of low-polygon work is to do a lot with little; Do something good with limited number of polygons and with small textures. Limitations are set by the game engine and platform the content is for – these days low-poly is usually for mobiles and other handheld devices. One very good way of getting the most out of your limited resources is doing stylised designs. I recommend this: Start by designing for low-poly. One of the best examples of such styling is the look of World of Warcraft.
- Make use of every triangle. Sounds simple but is easy to overlook when people are used to modeling with quads or n-gons(more than 4 sided-polys). Since every polygon is triangulated(divided to triangles) anyway when exported to game engine(or rendered), you could just as well divide the polygons yourself. That gives you one more edge to define the shape with. The example shows how shape is created by placing edges dividing the quad polygons and what the result would be if the edges were misaligned – something you may get if you let the software triangulate for you.
- Model volume on the outside of the joints. This way, when the limb bends, the outside preserves shape even when bent ‘open’. The example shows setup you could use for knee or elbow and some others for fingers.
- Focus in modeling the profile and the main shape landmarks. Polygons not used for better joint deformation or for defining general shape are extra – something you can do without. Create that extra detail with texture-map, instead.
- Add shape with texture by drawing some shadows&highlights into textures. But do it sparingly. Strong always present shadows or highlights look false.
- Make holes with texture. Say you need a grate with lots of holes. Modeling them would mean a lot of polygons. Why not make plane and texture that with a transparent texture (if your game engine supports it)? You could even have two planes, one see-through grate above and other below it with a well/whatever deeper place painted on it. Simplest solution is of course ‘holes’ painted in the main texture.
- Use multiple textures on your object. Game engines(and other software) allow textures only up to a certain size. But if they allow multiple textures, you can get around the limitation. Of course don’t go adding textures beyond what the target device can comfortably handle. One main reason to use multiple textures is when your game engine allows replacing parts of geometry in game. Say you have a character with skin(texture1) and clothes(texture2). The latter texture(2) and the geometry it covers could be interchanged in-game to another version when character changes set of clothes or armor. Even if your engine doesn’t allow interchanging parts, using multiple textures is a good way to do many variations of one model.
- For more texture detail somewhere on your model make that part bigger in your UV-map. Sure this leaves less space for other parts, but some areas are more important than others (character face for one). Example has the gargoyle skin-texture with uvw-map overlayed.
- Paint your texture in 3D-painting software and detail futher in 2D-software. Sure you could paint all in 2D-software like Photoshop but there is no comparison to 3D-painting. Simple thing like making a straight line around a character becomes a pain if you have only 2D-paint to work with. Here are several 3D-paint softwares listed. Tattoo for one is free for personal non-commercial use.
- Colour your textures by hand. Painting in shades of grey, black’n white, and then overlaying colour on might be easier, but if you instead both choose and paint the colours by hand, the end result is more vibrant and alive. Same applies to gradients. They tend to be too mechanical, too perfect. Paint the colour-shift yourself.
- Use duplicate-parts in your character/object. Hands can often be mirror-copies of each other, same with legs. This is how you can save in UV-space and hence make all parts bigger in the UV-map and so more detailed. This is ever more true with objects like buildings where you can use same textures over and over. Clever and creative UV-worker can create many variations from just one texture-map.