Immersion Techniques in 3D Environments
In games, 3D guided tours, games, environmental demos, games, architectural presentations, games; no matter the scene, the purpose is always to make the user feel like he’s actually in your demo. To create the illusion of being part of the world, developers use various techniques to maintain the illusion throughout the experience. In this article we will explore some of them, starting from the inside towards the outside boundary.
Naturally Blocking Line of Sight (LOS)
Almost every 3D environment starts out as a cube, or box shape. Our job is to make you feel like you are in a fully realized world with no boundaries. The first step in this process is to limit where the user can go while making it seem like the area stretches on for miles. Whenever we constrain the player by blocking his progress, the player needs to feel like it’s a natural obstacle that he can go around, not the “end of the level” wall. The realism of the scene comes in the illusion of vastness, of a complete world, not a shoe box.
Depending on your environment, there are many natural ways to block both line of sight and movement of the player. In a city scene, you can use a car pile-up, construction, ending the lane in a large building like a library or museum, police road block due to accident or robbery, the list goes on as far as your imagination. All of these will make the player feel like he’s in a real environment and serves the purpose of hiding the level border and adding realism.
Perspective Range
The 3D version of “Smoke and Mirrors”. Think of a level as having 3 stages of distance in order to provide the perspective of range and distance. The inner level is the playable field, with natural boundaries to constrain the player within it. The mid-level contains simplified geometry to provide ambience and a sense of scale. The outer level provides a sense of place or location in the world. This is mostly in part because of our perspective. As it changes, objects that are closer appear to move faster than objects that are far away.
Another great tool is distance fog. Representing the aspect of visual range, its a rolling fog that increases in strength the further away an object is. Its also a great way to represent heat haze and smog.
Skydome vs. Skybox
The cherry on top, you can’t have a world without atmosphere, sky and clouds. There are two popular ways to add this, Skydome and Skybox.
A Skydome is a sphere or half sphere that goes around your entire level. Effects like lens flare and animated clouds can add dynamic realism to the scene. It’s very easy and quick to make, but it adds more geometry to your scene and the slight spherical skewing may be noticeable.
A Skybox gives the sense of limitless sky and distance. It achieves this through a camera trick. In the development environment or game engine you create a cube outside of your box shaped level. To this you apply 6 seamless skyline images to each of the internal walls of the cube. With the cube as a reference, you tell the walls of your main level to “look through” the cube walls. Its almost better to describe it as a portal to a wall in the small cube, but since you can never reach the walls, its a visual illusion. And as it encompasses the entire level, it feels like a seamless sky.
God rays, or light cones and light bloom effects really add realism to the entire environment. Crisp shadows take care of all the rest.
Keeping all these techniques in mind when you create a level along with game play elements or directional flow of the tour/action will give you a very professional end product. And the entire reason we do all this work is so that no one notices that we DID do all this work, it has to feel natural. Mother Nature is a hard task master. ;)
-Juan
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Very nice Juan, extremely informative.
One of my favorite examples of some of these techniques, the ‘3 stages of distance’ in particular, is Half-Life 2 (esp. Episode 2) — they did a great job in that game of limiting the player’s movement very narrowly, yet used some clever geometry / skybox techniques to give you the sense that the world wasn’t just a little corridor.
I dig this level-design-specific stuff on 3DVIA. Perhaps gearing up for some new game content? :)
HOLY WOW
Ahh Half-Life 2 :) They do fantastic work and if anyone is looking for a nice little demo showcasing the techniques discussed above, I invite you to download the Half-Life 2 Lost Coast demo on Steam. Steam is a digital distribution portal by Valve the makers of Half-Life. All of it is free, and the demo is a fantastic interactive walkthrough.
I have the Wall•E video game with it I got Ratatuie (however you spell that name) and Cars videogame demos. I printscreened cars and found no atmosphere. That was because the atmosphere was actually a sphere over your head, following the game player around wherever Mcqueen goes. The game is actually pretty fun, but I switched to burnout paradise because of its 250 miles of HD realistic (should’nt say the same thing twice, I guess!) enviorment. Cars is similar game except it’s made for kids.
Lots of shockwave and virtools 3d games use these. Bee movie game is a good example for games I’ve played.
As far as I have seen with printscreen (Maybe that should be the ad: Everything you will have seen with print-screeeeeen with the classic annoying music) The skybox is better for traveling far distances like in long races and skydome is for having limited space like in the 3d roller coaster ride (See if it’s skybox or skyyyyydoooome when you download printscreen right-at-hoooooooooooooooooooooooome!)
Today!
Tomy you would be correct, I use skydomes mostly for stationary scene’s that contain limited movement or for a single render. Skyboxes for everything interactive like a game.
I use sky domes primarily in limited size worlds where I want to animate it (Moving clouds, etc). Sky boxes are more infinite and can be coded in (in VRML). Other things like fog combined with level of detail help also. Combine these with realistic light mapping and decent physics and you can create a pretty real looking, immersive experience.
Excellent article Juan!
I believe you can still add some dynamic elements to skyboxes, and you can most definitely mix and match to create the most immersive experience with the tools available.
Thanks rhalstead :)
Very nice, keep up the good job on the articles.
Video games? Reminds me of what I have been trying to say for a while, just couldn’t find the place for it. Anyone know how to get models from Myst III with printscreen? I still have it and it says it uses DirectX (DirectX8.0).
Hello nice to meet you…
Nice to meet you too Kevin
i don’t know if you choosed rightly Fallout 3 for description,because many users from here are from india.F3 was forbidden for seel in india because of the two-headed cows…unfair…
sorry dude, you are missing there a fabulous videogame. ITs a pitty nowadays people still censureing art, just becuase a 2headcow character they censure a whole game, come-on is SCI-FI!!!.
I have a question maybe you can unswer, what happens if NAture decides it?
regards