Bones1 - This shot shows the face of the 3700 polygon skeletal demo character in wireframe mode with bones and blended vertices showing. This character has over 40 bones in his head alone! Notice that many of the strands of hair actually have bones in them so they can be individually animated. The colors on the vertices represent the number of bones that influence those vertices, Green = single bone influence, Red = 2-bone blend, Pink = 3, Light Blue = 4 and White = 5 or higher. 

Detail1 - 2 - These shots illustrate increased polygon levels over standard Unreal and Unreal Tournament scenes that the engine can now handle.

Face1-4 - These shots illustrate facial animation using our skeletal animation system. As shown in Bones1.jpg, this character has several bones in his face for controlling muscles, lips, eyebrows (the eyebrows were missing from this model but please imagine that they're there!), teeth, eyes, and even hair. These animations were created by hand but at Epic we plan to use facial motion capture on our future game titles. Imagine a game like Deus Ex with facial motion capture so detailed you can zoom in on the characters and see completely realistic expression on their face to match the dialog. 

Skel1 - 4 - The character model in these shots weighs in at 3,700 polygons. This is roughly 5 times more detailed that the most detailed characters you saw in either Unreal or Unreal Tournament. The skeletal animation system, using quaternion-based interpolation, allows for both loss-less and lossy compression of the motion data. The rendering pipeline of the engine is being modified so that characters (and additive solid geometry) can be processed through the hardware T&L pipeline of Direct3D cards with that feature. That means the theoretical limit for polygons and, more importantly, the numbers of characters on screen jumps substantially for applications intended for Microsoft X-Box or computers equipped with hardware T&L-capable cards like Nvidia GeForce or ATI Radeon and the myriad of others that will follow. The new features of DirectX 8 in particular will enable skeletal characters to make full use of the hardware to accelerate rendering of smooth-skinned meshes.

LOD - The Unreal Engine features continuous progressive level-of-detail support (LOD) for meshes. Here our 3,700 polygon test model is shown from a distance with the LOD settings manually adjusted to simulate the automatic distance-based polygon reduction done by the engine. The upper pictures shows the model in varying polygon counts from 1890 visible polygons down to 266 visible polygons. The lower picture approximates how distant the character would be before the system reduced the polygon counts to those levels by shrinking the picture to the same proportion as the polygon counts reduction. Developers can also instruct the Unreal engine to reduce polygon counts based on the number of characters on screen which helps keep performance stable when scenes contain a lot of characters. Can you see the difference, at this size, between 1890 polygons and 988 polygons? The engine continuously reduces polygon counts on the fly. If you think it's difficult to see the differences here, it's even less obvious when the characters are moving and the distances are correct.

Terrain1 - 4 - One of the most exciting new features of the Unreal Engine is large scale terrain support. Epic Game programmer Jack Porter, who programmed the terrain system, supplied this write-up on the large-scale terrain feature:

The castle is created with the same BSP technology seen in Unreal and Unreal Tournament.  It has a little higher polygon count than a typical Unreal Tournament level, but is created exactly the same way.  What we've done is integrated an outdoor terrain engine, and made it coexist with the BSP engine so that the BSP areas and the terrain areas can be seamlessly joined together. The terrain is based on a heightmap system. The heightmaps can be generated with 3D terrain software such as Bryce, and tweaked in Photoshop. This particular terrain has around 128,000 polygons with the entire scene weighing in near 170,000 polygons.  It is rendered using the Hardware Transform capabilities of the Nvidia GeForce 256. 

The level designer designs the terrain in layers. Each layer has its own texture associated with it, as well as an "alpha map" describing how the layer should blend in with the other layers. For example, in this scene we have six layers, including rock, grass, dirt, a mottled grass/rock layer, and a shadow layer.  The use of layers and the alpha maps allows the level designer to create a detailed terrain environment without any obvious texture tiling artifacts. The trees are meshes, also rendered using hardware transform, and they have alpha textured leaves to allow smooth blending between the leaves and the background.

In UnrealEd, the level designer can control the terrain heightmap and layers, and instantly see the results in UnrealEd's 3D view in the bottom left corner.  Adjusting the TerrainInfo actor's properties (second editor screenshot) changes the properties of the terrain layers.

Snow 1 - 2 - To demonstrate that terrain can be used in playable game levels we quickly put together this Unreal Tournament Capture The Flag level using terrain. 

So there you have a look at some of the newer technology in the Unreal Engine. Please note that all of this technology will work on all supported PC and console platforms. Thanks to skeletal animation programmer Erik De Neve and terrain programmer Jack Porter for their input.
