Video Games as Soft Real-Time Simulations
Most two- and three-dimensional video games are examples of what computer scientists would call soft real-time interactive agent-based computer simulations. Let's break this phrase down in order to better understand what it means. In most video games, some subset of the real world -or an imaginary world- is modeled mathematically so that it can be manipulated by a computer. The model is an approximation to and a simplification of reality (even if it's an imaginary reality), because it is clearly impractical to include every detail down to the level of atoms or quarks. Hence, the mathematical model is a simulation of the real or imagined game world. Approximation and simplification are two of the game developer's most powerful tools. When used skillfully, even a greatly simplified model can sometimes be almost indistinguishable from reality and a lot more fun.
An agent-based simulation is one in which a number of distinct entities known as "agents" interact. This fits the description of most three-dimensional computer games very well, where the agents are vehicles, characters, fireballs, power dots and so on. Given the agent-based nature of most games, it should come as no surprise that most games nowadays are implemented in an object-oriented, or at least loosely object-based, programming language.
All interactive video games are temporal simulations, meaning that the vir- tual game world model is dynamic-the state of the game world changes over time as the game's events and story unfold. A video game must also respond to unpredictable inputs from its human player(s)-thus interactive temporal simulations. Finally, most video games present their stories and respond to player input in real time, making them interactive real-time simulations.
One notable exception is in the category of turn-based games like computerized chess or non-real-time strategy games. But even these types of games usually provide the user with some form of real-time graphical user interface.
What Is a Game Engine?
The term "game engine" arose in the mid-1990s in reference to first-person shooter (FPS) games like the insanely popular Doom by id Software. Doom was architected with a reasonably well-defined separation between its core software components (such as the three-dimensional graphics rendering system, the collision detection system or the audio system) and the art assets, game worlds and rules of play that comprised the player's gaming experience. The value of this separation became evident as developers began licensing games and retooling them into new products by creating new art, world layouts, weapons, characters, vehicles and game rules with only minimal changes to the "engine" software. This marked the birth of the "mod community"-a group of individual gamers and small independent studios that built new games by modifying existing games, using free toolkits pro- vided by the original developers. Towards the end of the 1990s, some games like Quake III Arena and Unreal were designed with reuse and "modding" in mind. Engines were made highly customizable via scripting languages like id's Quake C, and engine licensing began to be a viable secondary revenue stream for the developers who created them. Today, game developers can license a game engine and reuse significant portions of its key software components in order to build games. While this practice still involves considerable investment in custom software engineering, it can be much more economical than developing all of the core engine components in-house. The line between a game and its engine is often blurry.
Some engines make a reasonably clear distinction, while others make almost no attempt to separate the two. In one game, the rendering code might "know" specifi-cally how to draw an orc. In another game, the rendering engine might provide general-purpose material and shading facilities, and "orc-ness" might be defined entirely in data. No studio makes a perfectly clear separation between the game and the engine, which is understandable considering that the definitions of these two components often shift as the game's design solidifies.
Arguably a data-driven architecture is what differentiates a game engine from a piece of software that is a game but not an engine. When a game contains hard-coded logic or game rules, or employs special-case code to render specific types of game objects, it becomes difficult or impossible to reuse that software to make a different game. We should probably reserve the term "game engine" for software that is extensible and can be used as the foundation for many different games without major modification.
Clearly this is not a black-and-white distinction. We can think of a gamut of reusability onto which every engine falls. One would think that a game engine could be something akin to Apple QuickTime or Microsoft Windows Media Player-a general-purpose piece of software capable of playing virtually any game content imaginable. However, this ideal has not yet been achieved (and may never be). Most game engines are carefully crafted and fine-tuned to run a particular game on a particular hardware platform. And even the most general-purpose multiplatform engines are really only suitable for building games slot gacor in one particular genre, such as first-person shooters or racing games. It's safe to say that the more general-purpose a game engine or middleware component is, the less optimal it is for running a particular game on a particular platform.
This phenomenon occurs because designing any efficient piece of software invariably entails making trade-offs, and those trade-offs are based on assumptions about how the software will be used and/or about the target hardware on which it will run. For example, a rendering engine that was designed to handle intimate indoor environments probably won't be very good at rendering vast outdoor environments. The indoor engine might use a binary space partitioning (BSP) tree or portal system to ensure that no geometry is drawn that is being occluded by walls or objects that are closer to the camera. The outdoor engine, on the other hand, might use a less-exact occlusion mechanism, or none at all, but it probably makes aggressive use of level-of-detail (LOD) techniques to ensure that distant objects are rendered with a minimum number of triangles, while using high-resolution triangle meshes for geome-try that is close to the camera.
The advent of ever-faster computer hardware and specialized graphics cards, along with ever-more-efficient rendering algorithms and data structures, is beginning to soften the differences between the graphics engines of different genres. It is now possible to use a first-person shooter engine to build a real-time strategy game, for example. However, the trade-off between generality and optimality still exists. A game can always be made more impressive by fine-tuning the engine to the specific requirements and constraints of a particular game and/or hardware platform.
Engine Differences Across Genres
Game engines are typically somewhat genre specific. An engine designed for a two-person fighting game in a boxing ring will be very different from a massively multiplayer online game (MMOG) engine or a first-person shooter (FPS) engine or a real-time strategy (RTS) engine. However, there is also a great deal of overlap-all 3D games, regardless of genre, require some form of low-level user input from the joypad, keyboard and/or mouse, some form of 3D mesh rendering, some form of heads-up display (HUD) including text rendering in a variety of fonts, a powerful audio system, and the list goes on. So while the Unreal Engine, for example, was designed for first-person shooter games, it has been used successfully to construct games in a number of other genres as well, including simulator games, like Farming Simulator 15 ( FS 15 mods ) and the wildly popular third-person shooter franchise Gears of War by Epic Games and the smash hits Batman: Arkham Asylum and Batman: Arkham City by Rocksteady Studios.
Making plastic parts is one of the most efficient ways to design and manufacture parts. In numerous cases these days, it is necessary to join two or more plastic parts together. Fortunately there are a wide variety of ways you can do this. I want to show you five of the best ways to accomplish this just like the pros and not like the other guys.
Before we discuss the exact methods you will need some information about what you are trying to accomplish. Why is this important? To choose the best method to join two parts you must know exactly why the parts need to be joined. There is a big difference depending on your design needs how the part should go together. Here some examples of things to look at on your list of requirements.
Make a list of your requirements which will help you find the best way to find out how to proceed. Now let us get to some solutions.
Using screws is a very common way to assemble plastic parts. The advantages are that anyone with the ability to turn a screw can assemble the parts. Screws can be used to join plastic parts to different materials like metals and composites. This is also easy for smaller volumes. That said one disadvantage is that it costs more time, money and labor as the number of parts increases. Assembly labor or expensive machinery is required for high volumes. Screws do allow for disassembly but wear out the screw pocket if the product is disassembled frequently. Using some adhesive will lock in the screw.
The general practice is to have the hole molded on one part for the screw to go through. The part to be joined to the first will have a pilot hole. The pilot hole is smaller than the screw threads. When the screw is first driven into the pilot hole it will cut into it. This gives a strong joint for the screw to clamp both parts together. Using a metal insert can increase strength of the joint and allow more frequent disassembly.
As a general rule use screws with fat heads like a pan head or button head screw. Flat head screws should not be used as the cone shape head will over stress the plastic. Be cautious if you are joining rubber parts with screws.
One of the most popular methods for joining two plastic pieces is using hooks. A hook, sometimes called a snap, looks like a barb on a fishing hook. This hook snaps into a slot in the part it is being joined to. A hook can be setup for either a permanent or temporary joint.
If the hook is shaped like a fish hook with a very pointed barb, and the slot is not accessible that is ideal for a permanent joint. Toys and small appliances frequently use this attachment method.
If you want a removable joint, like a battery cover, the hook should have no back angle so it acts more like a detent. A detent is better if the parts must be removed a put back together. One good example of this is a Fastex buckle which can be found at here. You probably have seen these on luggage, baby seats and outdoor gear.
Adhesives can be used to join parts easily as well. Adhesives, like epoxy, are not only good at bonding plastics but can be used to bond plastics to metal, composite, or ceramic. If correctly selected, the joint can also seal water, dust and other contaminates out. Since each adhesive is different, follow the directions and warnings given by the adhesive manufacturer. You should consider using adhesives as permanent.
Be careful when selecting adhesives if the product will experience hot and cold temperatures in regular cycles. Some adhesives will be better choices depending on the conditions the product is subjected to. Be sure to look at which materials you are bonding and make sure the adhesive will work with all parts to be bonded. Special care should be taken with adhesives if the parts they are used on come in contact with sensitive body parts.
On approach that gets over looked is to not have separate parts at all. Storage boxes can use a living hinge to allow the box and lid to be molded as one part. One example is this battery box. Living hinges are a great way to simplify no matter if you plan to make a 100 or 1 million parts. Material selection is very important with living hinges so do your homework. Living hinges are generally a good way to attach parts but special steps must be taken if the hinge is permanently bent.
In a high volume production setting, sonic welding can be a fast and inexpensive method to joint two parts. In many cases the two parts are mirrored (they often are the left and right halves of some larger part) giving the parts a natural joining area. Sonic welding requires both parts to be specially designed for the task and requires a sonic welder. Once you have the proper machinery and setup, welding the material takes a few seconds. As with other methods, check to see if the materials will join together. Sonic welding makes good joints but can sometimes not align the parts exactly. The designer should make allowances for any misalignment that may occur.
Now that you know about these five methods of joining plastics part together and understand what you need to know before you choose one of them let review what I have said here. Make sure you know whether a joint is permanent or temporary. Check to see what the other requirements are. Select the method that best suits your needs.