: Design copyright (c) 2005 by Paul Greveson :
  - Tips & Tricks - Low Polygon modelling -

I've decided to gather together a little collection of tips, tricks and ideas to bear in mind when modelling low-polygon things for games. When I say low-polygon, I mean pretty much anything under 1000 triangles.

Optimisation:

When modelling with a low polygon budget, you need to keep one thing in mind - optimisation. Why use
4 triangles to define a shape when you can use 3, or even 2? Always try to get the desired effect without going overboard on geometry. Here I've assembled a pretty extreme example. I'm assuming this is not going to bend - if it was, it would require more geometry to allow it to deform properly.

Fig. 1

Anything in a straight line, with more than one edge defining that line, can be optimised down to one edge, as I have done to the lower part of this object. As you can also see on the upper part of the object in the side view, I have collapsed the extra edge down to a single vertex half-way along it. This saves geometry, and looks almost exactly the same in silhouette.
Do not collapse edges which are defining large changes in direction in the shape of the model - it is the change in direction that defines the silhouette of the model.

Here is another place where optimisation works well - a lot of people like to have their meshes all as one connected piece, but sometimes this is unneccessary and wastes triangles. Take a look at the image below.

Fig. 2

On the right is a model where the smaller cube is joined geometrically to the larger cube. On the left is a model that looks identical, but uses 6 less triangles due to the fact that the cubes are not physically connected.
6 triangles may not sound like much of a saving, but believe me, it all adds up...
Of course, this technique may be unneccessary in certain situations - such as higher polygon counts, the connection of meshes might make it easier to UV-map and animate, and the 6 triangles would be of no consequence. This is also the case on console games, where polygon counts are higher but texture resolution lower. There are pros and cons for both methods and it really depends on the situation and the modeller. It's up to you!

Edge Turning:

In low-polygon modelling, edge placement can be vital and even one or two slight changes can affect the look and quality of the whole model. Often just by "turning" an edge, you can make your model look smoother, and/or deform better during animation.

Fig. 3

Fig. 3(a) shows what edge turning actually is - changing the "inside edge" of a quadrilateral to attach between opposite vertices.
Fig. 3(b) shows how turning edges can make geometry look neater and less likely to "shear" when animating. Generally it is a good idea to have interior edges as short as possible.
The two edges turned in Fig. 3(b) were changed from being "long" edges to shorter edges. Long, thin triangles are best avoided - turning edges is a good way to combat this.

More to come later - I will add to this document as and when I learn new techniques and find the time to update the site.