‘Thematic consistency’ describes a sense of unity in a piece of art. It is very important in level design.
The worst and most amateurish type of thematic consistency is simple: no thematic consistency. These levels draw visual vocabulary from many different sources and mix them haphazardly. This is common among beginner level designers. These maps are easy to pick out. In order to avoid the no-consistency problem, level designers generally go through a ‘hyper-consistent’ phase where they run to the other end of the spectrum. Instead of everything being chosen randomly, everything looks the same. Take this example: the classic Counter-Strike map de_dust:
Dust’s visual vocabulary is limited to a very small number of design elements. Everything comes from the same narrow band of tan and yellow colors. To make a hyper-consistent level, you simply make sure that every part conforms to your single narrow design theme.
This type of design will not provoke a negative emotional reaction, it will not provoke a positive one either. It lacks the ‘pop’ of really great art. Also note that that it cannot look real, because the real world very rarely conforms to a totally consistent visual theme. There are very few places on Earth, save Antarctica, where everything fits together visually with this level of consistency. Hell, even on Antarctica you will find meteors from time to time.
Obviously hyper-consistency sucks. The solution is to come full circle and start breaking consistency again. There are several ways to do this.
The first way is ‘multi-theming’. This essentially means taking multiple artistic themes, each fully internally consistent, and applying them to different parts of a level. Note that this does not imply mixing the themes at any point. It means that different parts of the level conform to different themes. These different parts can be entire areas, or specific ‘pieces’. So, to make a multi-themed level, you just make sure that every part conforms to one of your narrow design themes.
For example, I was consciously multi-theming when I created DM-Lightfalls and DOM-Aphrodite. In DM-Lightfalls below, I used two themes: the airy verdant jungle, and the blue alien metal. Here they are quite cleanly separated, with a structure of blue alien metal surrounded by a verdant jungle backdrop. There are no parts of the level that do not firmly fit within one or the other theme.
In DOM-Aphrodite, I got more creative. There are three themes: Greek classical stonework, wooden and iron scaffolding, and the same verdant jungle look from DM-Lightfalls. You should be able to see that the elements are mixed more organically than in Lightfalls. Note, however, that there is no single piece that conforms to more than one specific theme. The trees are pure jungle, the statues are pure Greek, and the walkways are pure wood and iron. You don’t see any wooden walkways, for example, with white stone parts.
Multi-theming this way can get you very far, especially with non-realistic themes. Allow me to p1mp myself here and note that I won a very expensive copy of 3dsmax with Lightfalls, and Aphrodite was a finalist in the Make Something Unreal contest. This stuff works.
If you want to do really tight non-realistic maps, however, or just decent realistic ones, you need something else.
What you need goes beyond multi-theming the level. It almost comes full circle, back into thematic inconsistency territory. But instead of being haphazard, this type of inconsistency is interesting while still maintaining an underlying sense of unity.
Organically multi-theming a level requires more than pure visual artistic vision. It requires a narrative context for the level. This means that you need to have thought out the social and physical conditions that created the environment in the first place. If all of the artwork is consistent with this specific narrative, it can be as visually inconsistent as you like on a surface level, but it will still come together as a unified whole.
If you want an example of this, go outside in almost any city. The visual appearance of the landscape is composed of countless different types of visual elements. There will be natural parts in the trees, bushes, and grass. There will be loud, colourful advertisements. There will be people sporting a hundred fashions, and cars in a hundred styles. Even the buildings will have been built over hundreds of years and conform to radically different architectural schools. Furthermore, these elements will be mixed in various frighteningly complex ways: Men and women of several subcultures lounge on stone and wood benches in a grassy park. Beside them is a 100-year-old bronze monument, half-built-over by a modern art nouveau masterpiece.
This stuff doesn’t look good in abstract. It uses every color and every shape. On the surface, there seems to be no consistency. But it all fits into a totally coherent narrative relating to how that city was built.
I present here my finest example of this type of organic multi-theming. You’ll notice many more colors, themes, and elements than Lightfalls or Aphrodite. But it fits together because it has a rational story behind it.
To execute an organically themed level like this, you must make sure every visual element can exist as a natural outgrowth of the narrative context of the level.
We had a big discussion about this article on this BeyondUnreal Forum Thread.