Creating ground-based objects such as buildings and silos proved to be tricky, so we chose a mixed approach. The main part of the building was created or imported in Bryce, placed on the terrain and rendered to achieve consistent lighting and shadows and colour with the terrain. Then, during a game, sprites were overlaid, allowing the building to interact or animate. Care had to be taken with lighting and texturing the sprites to ensure visual consistency.
Here's a closeup of a pair of silos that Sheryn modelled and rendered in Bryce:
Enemy Design John Sledd was originally contracted to produce the sprite artwork, based on sketches provided by David. Sadly, John was unable to continue due to family commitments so David took over the role.
Out of the hundreds of ideas for enemies, most do not progress beyond a rough sketch. Often, what looks good on paper fails to impress on-screen. Due to the amount of work required to take an idea all the way to a finished product, unworkable ideas need to be culled as soon as possible. One that made the grade was the Shuriken, a deadly slice 'n dicer inspired by the tools of Mrs. Tweedy in the film Chicken Run.
The next stage is to take the sketch and build a 3D model of it. Cinema 4DXL was used because it's very stable, exports alpha channels, has a good interface and a fast renderer. Here, the blades of the Shuriken are tilted slightly in order to better catch the light when animated, providing useful visual clues in what would otherwise be a very small, flat object.
The model is animated over 6 frames in such a way that the animation can loop seamlessly:
Alpha frames are also created. These determine the translucency level of each pixel in the animation. This allows the sprite to have clean, anti-aliased edges - the lack of which is a common problem in sprite-based games. Without alpha maps, artists usually have to add black edges to their sprites and carefully watch the backgrounds over which the sprites are drawn.
The final animated Shuriken, complete with anti-aliased edges: