Plant No Other Tree

“Have you people ever seen … a tree?” bellows the voice of Three Dog, the talkative Galaxy News Radio presenter in Fallout 3. After your visit to the barren outback of the Capital Wasteland, you most certainly have.


Look past the soot and scorch marks, and the trees that line the game’s devastated mid-Atlantic landscape look like those you might find in your own backyard. The branches protruding from their trunks are formed with a quirkiness that nearly equals the work of Mother Nature herself. And if you make the trip to the unexpectedly lush settlement of Oasis at the northern edge of the map, you get the impression that the virtual forest wasn’t created by human hands at all. It looks completely natural, like it has organically intruded on the Capital Wasteland and is planning to overgrow the entire landscape, one ruined block at a time.

The people at Bethesda Softworks, the videogame developer that created Fallout 3, didn’t model all of those trees themselves. Instead, they used a piece of middleware called SpeedTree to automatically generate the game’s foliage and make it look as though it’s a natural part of the landscape. “We even built in features that allow game developers to make their trees look scorched or dead, like in a post-nuclear environment,” says Kevin Meredith, Director of Business Development at Interactive Data Visualization, the South Carolina-based company that developed and sells SpeedTree. “They can darken the bark or add a burned-looking texture to it, remove the leaves or modify the code in order to bend the physics of the trees.”

Of course, SpeedTree wasn’t developed exclusively with Fallout 3 in mind. The origins of the software go back long before the game was even a twinkling in Bethesda’s eye. SpeedTree has its roots in a golf simulation that IDV worked on at the start of the new millenium. Because the rustle of the trees is a well-known natural cue to golf players about the direction and speed of the wind, IDV scoured the market for software that could make the trees on their virtual golf course react naturally to simulated weather conditions and came up empty-handed. So they decided to develop the software themselves. “After a while, we were so impressed with our trees that we decided to make a product out of them,” Meredith says.

IDV didn’t have much to do with the videogame industry at that time. It was a services firm, working primarily for urban development projects, architects and the like. But their invention was soon found invaluable for game developers.

The first commercial videogame that incorporated an early version of SpeedTree was Trials of Atlantis, a 2003 expansion of the MMOG, Dark Age of Camelot. After that, SpeedTree was licensed for use with games such as Auto Assault, WWII Online, Vanguard: Saga of Heroes, Irth Online, as well as integrated with Unreal Engine 3.0. Once IDV added real-time physics to their middleware, it started popping up in more mainstream titles. SpeedTree was named the sole foliage middleware partner for the “next-generation Xbox platform” (a.k.a. Xbox 360) in March 2005. Later that month, Linden Labs licensed the technology for use in the virtual world Second Life. Electonic Arts used SpeedTree in its own golf game, Tiger Woods PGA Tour 06, and Bizarre Creations used it in its racing simulator, Project Gotham Racing 3, where the displacement of air caused by speeding vehicles made the leaves in the background rustle appropriately.

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But the breakthrough implementation of SpeedTree came with 2006’s The Elder Scrolls IV: Oblivion, which used a version of SpeedTree that Bethesda modified according to research conducted with the University of Maryland’s geology lab. The developers deepened their understanding of how soil erodes, how trees grow naturally in a landscape and how rocks form, and used that knowledge to make the first entirely computer-generated forest in a videogame. “We’re very proud of what they did with our technology,” Meredith affirms. “It showed the endless possibilities in solid videogaming applications.”


After Oblivion, SpeedTree quickly became a household name in videogame development. The technology was featured in games like Call of Duty 3, Resistance: Fall of Man, Grand Theft Auto IV and Lord of the Rings: Conquest, not to mention more recent outings like Divinity II: Ego Draconis, Batman: Arkham Asylum and Empire: Total War. Big-name game publishers like EA, Take Two and Activision are recurrent licensees. And the development of the software itself has kept pace with its sales: SpeedTree now offers a library consisting of 150 foliage species, ranging from American Elms and Madagascan Baobabs to Weeping Willows and Cinnamon Ferns. The company has also developed a separate piece of middleware, SpeedGrass, to create naturally-looking soil overgrowth, and it’s recently obtained its first licensee in the movie business. Industrial Light and Magic, one of the vessel companies of George Lucas’ Skywalker Ranch empire, is using SpeedTree Cinema in an as-yet-unnamed animated movie.

It’s not that 3D modelers didn’t know how to make trees before SpeedTree came along. The problem is that it was an extraordinarily time-consuming chore. IDV tackled that problem by coding some basic laws of nature into computer algorithms. The software basically copied the natural principle that all growth in a tree takes place at the tip of a stem, where leaves can grow but auxillary buds can also develop into an entirely new stem, creating branches. Randomizing that process, they could make it so that no two software-generated trees, even of the same species, look the same. Then they added some physics properties to all of these components to make the self-generated trees react believably to wind and rain.

The process at the heart of of SpeedTree is called procedural modeling, and it’s currently taking the videogame development world by storm. The idea is that by using parametrical data to model objects in videogame environments instead of crafting them by hand, you can not only save time but achieve a more natural-looking final product as well. Procedural modeling is also used for building realistically-looking roads (with random concrete deformation) and strewing props across a backdrop in a way that it looks like it’s been done haphazardly.

Methods like SpeedTree are clever ways to develop games with fewer headaches and make game development cheaper – hand-crafting a good tree can take up to several weeks of labor for a modeler, so the advent of procedural modeling offers the prospect of working with smaller development teams and, therefore, smaller development budgets. It’s graphic design 2.0, relegating 3D-modeling craftsmanship only to where it’s absolutely necessary and building the rest of the environment through algorithms. “It saves you a lot of time, especially for objects that are both generic and hard to model right, like trees,” says Bert Van Semmertier, a Graphics Engineer at Divinity II: Ego Draconis developer, Larian Studios. “But an artist always wants to have maximum control over his material, and the possibilities of procedural modeling are limited by the mathematical principles behind it. You could build a house using algorithms and computer-generated brick textures, but hanging a poster on one of its walls would be much harder.”


Procedural modeling will probably never be able to build landmark backdrops like Assassin’s Creed II‘s almost pixel-perfect renditions of the Santa Maria del Fiore cathedral and the Santa Croce basilica. With natural objects, the importance of honest handiwork hasn’t entirely vanished, either. Responding to explicit demand from game developers, IDV has built a new hand-modeling tool into the recently released version 5.1 of SpeedTree. “At the end of the day, game development is about doing your own thing,” says Meredith. “If the goal is to save time and means, procedural modeling is a great method. But if someone wants to make his own, perfect virtual tree, he should be able to do so as well.”

The scorched trees in Fallout 3 look perfect enough, though. The MacGuffin in the main quest of the game was a so-called Garden of Eden Creation Kit, a piece of technology with the power to turn barren wasteland into fertile ground. It’s a fantasy device first dreamed up by the creators of the first Fallout game, developed by Interplay back in 1997. Little did they know that the people making one of the future installments of the series would actually use such a device. Most gamers were probably not aware that the makers of the game actually simulated virtual life with SpeedTree in order to make the Capital Wasteland look so natural.

To them, it’s just a bunch of trees.

Ronald Meeus ([email protected]) is a freelance contributor to The Escapist.

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