XCOM Apocalypse

I worked on several of the alien terrain tile sets for this game, along with the UFOs and a couple of the creatures.

 

I've actually very little left over from this game in my archives but a few of the tile sets are as follows:

 

Creating 3D isometric maps for XCom games

The editor was an updated version of the one used for the earlier xcom games.

Every tile was designed to occupy a volume of space. Many tiles had multiple versions showing a succession of destroyed states.

In the description off each tile there was a series of properties such as ‘health value’ and ‘destroyed tile type’. when the health value was eroded away the tile would then be replaced by the ‘destroyed tile type’ (which in turn could have its own health and destroyed type). Chains like this could be as long or short as required. Tiles could of course also bed invulnerable.

This approach meant that potentially anything in the map could be blown apart and destroyed. This was made even more true in Apocalypse as tiles could also be flagged as supportive, and if a supportive tile was destroyed then those above it could also fall.

 

Tiles were complex data structures. Each one also had a reference to line of sight definition – this was a simple 4x4x4 grid – a sort 3d texture – where each cell was either solid or empty. There were a relatively small number of these solid line of sight definitions, but enough to approximate the 3D shape of any shape of tile created. This meant that the world was effectively broken into a 3d voxel grid where weapon fire could be accurately ray-traced. It was a ball ache to set up initially, as every tile had to have a line of sight definition assigned, but really made life easy later on as collision in game then became automatically generated from the map editor.

It was a genius approach, especially in the years before decent 3d raytracing – and one of the key identifying features of an xcom game. Players always loved being able to snipe enemy forces from right across the map through a couple of windows or blown open walls. It’s also a technique which I think useful to reinvent for use in conjunction with true 3D worlds and can think of lots of good mechanics you could use them for.

 

While some mission maps were hand crafted (especially apocalypse and the end missions of every game), many other mission maps in XCom games were made procedurally (especially in the earlier games).

 

The procedural rules would:

  1. Decide on the location type (e.g. farm, port, city etc)

  2. Then, using a look-up table specific to the location type selected a look up table would let a number of small hand crafted sections be chosen at random (though rules would restrict how often each piece could be chosen).

  3. Mix together these sections (with simple rules that specified which sections could be adjacent to which other sections).

 

The result was a vast number of possible layouts – for all intents and purposes near infinite, and unique to each user.

The procedural nature of these maps made the games feel more personal to each user.

The recent remake eschewed this approach and instead went for a large number of hand crafted maps instead, although with random starting points (which was a shame).

 

Sadly I don't have screenshots of the tools we used for these isometric games, but here's a few example screens from Apocalypse.

 

 

Scanning the models was tried, but was next to useless, and most of the ingame images were based on handcoloured photos of the original maquettes.

 

You can see some of Tim's original model photos over at his site:

http://www.tim-white.co.uk/pages/sculpturegallerypage1.html

 

I like Tim's artwork a lot - but the silhouettes and form of these creatures was too indistinct for this type of game.