Three-dimensional graphics (3D Graphics, Three Dimensions of Image, 3 Dimensions, Russian 3 dimensions) is a section of computer graphics, a set of techniques and tools (both software and hardware) designed to depict three-dimensional objects. It is most often used to create images on the plane of a screen or sheet of printed materials in architectural visualization, cinema, television, computer games, printed materials, as well as in science and industry.

A three-dimensional image on a plane differs from a two-dimensional one in that it involves constructing a geometric projection of a three-dimensional model of the scene onto a plane (for example, a computer screen) using specialized programs. In this case, the model can either correspond to objects from the real world (cars, buildings, hurricane, asteroid) or be completely abstract (projection of a four-dimensional fractal).

To obtain a three-dimensional image on a plane, the following steps are required:

modeling - creating a three-dimensional mathematical model of the scene and objects in it.

rendering (visualization) - construction of a projection in accordance with the selected physical model.

output the resulting image to an output device - display or printer.

However, due to attempts to create 3D displays and 3D printers, 3D graphics do not necessarily involve projection onto a plane

Modeling

The scene (virtual modeling space) includes several categories of objects:

Geometry (a model constructed using various techniques, for example a building)

Materials (information about the visual properties of the model, such as wall color and window reflectivity)

Light sources (direction, power, lighting spectrum settings)

Virtual cameras (selection of point and projection angle)

Forces and impacts (settings for dynamic distortions of objects, mainly used in animation)

Additional effects (objects simulating atmospheric phenomena: light in fog, clouds, flames, etc.)

3D modeling problem- describe these objects and place them in the scene using geometric transformations in accordance with the requirements for the future image.

Rendering

At this stage, the mathematical (vector) spatial model turns into a flat (raster) picture. If you want to create a movie, then a sequence of such pictures - frames - is rendered. As a data structure, an image on a screen is represented by a matrix of dots, where each dot is defined by at least three numbers: the intensity of red, blue and green. In this way, rendering converts a three-dimensional vector data structure into a flat matrix of pixels. This step often requires very complex calculations, especially if the illusion of reality is to be created. The simplest form of rendering is to plot the outlines of models on a computer screen using projection, as shown above. Usually this is not enough and you need to create the illusion of the materials from which the objects are made, as well as calculate the distortions of these objects due to transparent media (for example, liquid in a glass).

There are several rendering technologies, often combined together. For example:

Z-buffer (used in OpenGL and DirectX 10);

scanning surface. The color of the pixel will be the same as the color of that surface (sometimes taking into account lighting, etc.);

Ray tracing (ray tracing) is the same as scanline, but the color of the pixel is refined by constructing additional rays (reflected, refracted, etc.) from the point of intersection of the viewing ray. Despite the name, only reverse ray tracing is used (that is, from the observer to the light source), direct ray tracing is extremely inefficient and consumes too many resources to obtain a high-quality picture;

Global illumination (English: global illumination, radiosity) - calculation of the interaction of surfaces and media in the visible spectrum of radiation using integral equations.

The line between ray tracing algorithms is now almost blurred. So, in 3D Studio Max the standard visualizer is called Default scanline renderer, but it considers not only the contribution of diffuse, reflected and intrinsic (self-luminous color) light, but also smoothed shadows. For this reason, more often the concept of Raycasting refers to backward ray tracing, and Raytracing refers to forward ray tracing.

The most popular rendering systems are:

PhotoRealistic RenderMan (PRMan)

Due to the large volume of similar calculations, rendering can be divided into threads (parallelized). Therefore, for rendering it is very important to use multi-processor systems. Recently, there has been an active development of rendering systems that use GPUs instead of CPUs, and today their efficiency for such calculations is much higher. Such systems include:

Refractive Software Octane Render

AAA studio FurryBall

RandomControl ARION (hybrid)

Many manufacturers of CPU rendering systems are also planning to introduce GPU support (LuxRender, YafaRay, mental images iray).

The most advanced achievements and ideas in three-dimensional graphics (and computer graphics in general) are reported and discussed at the annual SIGGRAPH symposium, traditionally held in the USA.

You are probably reading this article on the screen of a computer monitor or mobile device - a display that has real dimensions, height and width. But when you watch, for example, the cartoon Toy Story or play the game Tomb Raider, you are looking at a three-dimensional world. One of the most amazing things about a 3D world is that the world you see could be the world we live in, the world we will live in tomorrow, or a world that lives only in the minds of the movie or game creators. And all these worlds can appear on only one screen - this is at least interesting.
How does a computer trick our eyes into thinking that when we look at a flat screen we see the depth of the picture being presented? How do game developers ensure that we see real characters moving around in a real landscape? Today I will tell you about the visual tricks used by graphic designers and how it all is designed and seems so simple to us. In fact, everything is not simple, and to find out what 3D graphics is, go to the cut - there you will find a fascinating story, which, I am sure, you will immerse yourself in with unprecedented pleasure.

What makes an image three-dimensional?

An image that has, or appears to have, height, width, and depth is three-dimensional (3D). A picture that has height and width but no depth is two-dimensional (2D). Remind me where you find two-dimensional images? - Almost everywhere. Remember even the usual symbol on the toilet door, indicating a stall for one gender or another. The symbols are designed in such a way that you can recognize and recognize them at a glance. That's why they only use the most basic forms. More detailed information about a symbol can tell you what kind of clothes that little person hanging on the door is wearing, or the color of their hair, such as the symbolism of a women's restroom door. This is one of the main differences between the way 3D and 2D graphics are used: 2D graphics are simple and memorable, while 3D graphics use more detail and pack significantly more information into a seemingly ordinary object.

For example, triangles have three lines and three angles - all that is needed to tell what the triangle consists of and what it represents in general. However, look at the triangle from the other side - a pyramid is a three-dimensional structure with four triangular sides. Please note that in this case there are already six lines and four corners - this is what the pyramid consists of. See how an ordinary object can become three-dimensional and contain much more information needed to tell the story of a triangle or pyramid.

For hundreds of years, artists have used some visual tricks that can make a flat 2D image seem like a window into the real 3D world. You can see a similar effect in a regular photograph that you can scan and view on a computer monitor: objects in the photograph appear smaller when they are further away; objects close to the camera lens are in focus, which means, accordingly, everything behind the objects in focus is blurred. Colors tend to be less vibrant if the subject is not as close. When we talk about 3D graphics on computers today, we're talking about images that move.

What is 3D graphics?

For many of us, gaming on a personal computer, mobile device, or an advanced gaming system in general is the most striking example and common way through which we can contemplate 3D graphics. All of these computer generated games and cool movies must go through three basic steps to create and present realistic 3D scenes:

1. Creating a virtual 3D world
2. Determining which part of the world will be shown on the screen
3. Determining what a pixel on the screen will look like so that the full image appears as realistic as possible

Creating a virtual 3D world
The virtual 3D world is, of course, not the same as the real world. Creating a virtual 3D world is a complex work on computer visualization of a world similar to the real one, the creation of which uses a large number of tools and which implies extremely high detail. Take, for example, a very small part of the real world - your hand and the desktop underneath it. Your hand has special qualities that determine how it can move and appear externally. The finger joints bend only towards the palm, and not opposite it. If you hit the table, no action will happen to it - the table is solid. Accordingly, your hand cannot pass through your desktop. You can prove that this statement is true by looking at something natural, but in the virtual three-dimensional world things are completely different - in the virtual world there is no nature, there are no natural things like your hand, for example. Objects in the virtual world are completely synthetic - these are the only properties given to them using software. Programmers use special tools and design 3D virtual worlds with extreme care to ensure that everything behaves in a certain way at all times.

How much of the virtual world is shown on the screen?
At any given time, the screen shows only a tiny part of the virtual 3D world created for the computer game. What is shown on the screen are certain combinations of ways in which the world is defined, where you make decisions about where to go and what to see. No matter where you go - forward or backward, up or down, left or right - the virtual 3D world around you determines what you see when you are in a certain position. What you see makes sense from one scene to the next. If you look at an object from the same distance, regardless of direction, it should appear high. Every object must look and move in such a way that you believe that it has the same mass as the real object, that it is as hard or soft as the real object, and so on.

The programmers who write computer games put a lot of effort into designing 3D virtual worlds and making them so that you can wander around without encountering anything that makes you think, “That couldn't happen in this world!” The last thing you want to see is two solid objects that can pass right through each other. This is a stark reminder that everything you see is a sham. The third step involves at least as many more calculations as the other two steps and must also occur in real time.

On the left is computer graphics, on the right is a mocap actor

Lighting and perspective

When you enter a room, you turn on the light. You probably don't spend a lot of time wondering how it actually works and how the light comes from the lamp and travels around the room. But people working with 3D graphics have to think about this because all the surfaces and surrounding wireframes and things like that need to be lit. One method, ray tracing, involves sections of the path that light rays take as they leave a light bulb, bounce off mirrors, walls and other reflective surfaces, and finally land on objects with varying intensities from different angles. This is difficult, because one light bulb can produce one beam, but in most rooms several light sources are used - several lamps, ceiling lamps (chandeliers), floor lamps, windows, candles, and so on.

Lighting plays a key role in two effects that give the appearance, weight, and external solidity of objects: obscuration and shadows. The first effect, shading, is where more light falls on an object from one side than from the other. The shading gives the subject a lot of naturalism. This shading is what makes the folds in the blanket deep and soft and the high cheekbones appear striking. These differences in light intensity reinforce the overall illusion that an object has depth as well as height and width. The illusion of mass comes from the second effect - shadow.

Solids cast shadows when light falls on them. You can see this when you observe the shadow that a sundial or tree casts on the sidewalk. Therefore, we are accustomed to seeing real objects and people casting shadows. In 3D, shadow again reinforces the illusion, creating the effect of being in the real world rather than in a screen of mathematically generated shapes.

Perspective
Perspective is one word that can mean many things, but actually describes a simple effect that everyone saw. If you stand on the side of a long, straight road and look into the distance, it appears as if both sides of the road converge at one point on the horizon. Also, if trees are close to the road, trees further away will appear smaller than trees closer to you. In fact, the trees will appear to converge at a certain point on the horizon formed near the road, but this is not the case. When all the objects in a scene appear to end up converging on one point in the distance, this is perspective. There are many variations of this effect, but most 3D graphics use the same point of view that I just described.

Depth of field

Another optical effect successfully used to create three-dimensional graphic objects is depth of field. Using my example with trees, in addition to the above, another interesting thing happens. If you look at trees close to you, trees further away will appear to be out of focus. Film directors and computer animators use this effect, depth of field, for two purposes. The first is to enhance the illusion of depth in the scene the user is viewing. The second purpose is that directors' use of depth of field focuses their attention on the subjects or actors that are considered most important. To draw your attention to someone other than the film's heroine, for example, a "shallow depth of field" may be used, where only the actor is in focus. A scene that is designed to give you a full impression will instead use "deep depth of field" to keep as many objects as possible in focus and thus visible to the viewer.

Smoothing

Another effect that also relies on tricking the eye is anti-aliasing. Digital graphics systems are very good at creating crisp lines. But it also happens that diagonal lines have the upper hand (they appear quite often in the real world, and then the computer reproduces lines that are more reminiscent of ladders (I think you know what a ladder is when you examine the image object in detail)). So, to trick your eye into seeing a smooth curve or line, the computer can add certain shades of color to the rows of pixels surrounding the line. With this “gray color” of pixels, the computer actually deceives your eyes, and meanwhile you think that there are no more jagged steps. This process of adding extra colored pixels to trick the eye is called anti-aliasing, and it is one of the techniques that are manually created by 3D computer graphics. Another challenging task for a computer is creating 3D animation, an example of which will be presented to you in the next section.

Real examples

When all the tricks I've described above are used together to create a stunningly real scene, the result lives up to the effort. The latest games, movies, and machine-generated objects are combined with photographic backgrounds to enhance the illusion. You can see amazing results when you compare photos and a computer generated scene.

The photo above shows a typical office that uses the sidewalk as an entrance. In one of the following photographs, a simple plain ball was placed on the sidewalk and the scene was photographed. The third photograph represents the use of a computer graphics program, which created a ball that actually does not exist in this photograph. Can you tell there are any significant differences between these two photographs? I think no.

Creating animation and live action appearances

So far we've looked at tools that make any digital image appear more realistic - whether the image is a still or part of an animation sequence. If it's an animated sequence, the programmers and designers will use even more different visual tricks to make it look like it's "live action" rather than computer-generated images.

How many frames per second?
When you go to see a blockbuster movie at the local cinema, the sequence of images called frames runs at 24 frames per second. Since our retinas retain an image for slightly longer than 1/24 of a second, most people's eyes will blend the frames into one continuous image of movement and action.

If you don't understand what I just wrote, let's look at it this way: this means that each frame of a movie is a photograph taken at a shutter speed (exposure) of 1/24 of a second. Thus, if you look at one of the many frames of a racing movie, you will see that some of the racing cars are "blurred" because they were driven at high speed while the camera was open. This blurriness of things created by fast movement is what we are used to seeing, and it is part of what makes an image real to us when we look at it on a screen.

However, digital 3D images are not photographs after all, so no blurring effect occurs when the subject moves in the frame during shooting. To make images more realistic, blur must be explicitly added by programmers. Some designers believe that it takes more than 30 frames per second to "overcome" this lack of natural blur, which is why games have been pushed to the next level - 60 frames per second. While this allows each individual image to appear in great detail and display moving objects in smaller increments, it significantly increases the number of frames for a given animated action sequence. There are other certain pieces of imagery where accurate computer rendering must be sacrificed for the sake of realism. This applies to both moving and stationary objects, but that's a completely different story.

Let's come to the end

Computer graphics continues to amaze the whole world by creating and generating a wide variety of truly realistic moving and non-moving objects and scenes. From 80 columns and 25 lines of monochrome text, graphics have advanced significantly, and the result is clear - millions of people play games and run a wide variety of simulations with today's technology. New 3D processors will also make their presence felt - thanks to them, we will be able to literally explore other worlds and experience things we never dared to try in real life. Finally, back to the ball example: how was this scene created? The answer is simple: the image has a computer-generated ball. It's not easy to say which of the two is genuine, is it? Our world is amazing and we must live up to it. I hope you found it interesting and learned another piece of interesting information.

Three-dimensional graphics do not necessarily involve projection onto a plane.....

Encyclopedic YouTube

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✪ Theory of 3D Graphics, lesson 01 - Introduction to 3D Graphics

✪ Computer graphics in cinema

✪ Lecture 1 | Computer graphics | Vitaly Galinsky | Lectorium

✪ 12 - Computer graphics. Basic concepts of computer graphics

✪ Lecture 4 | Computer graphics | Vitaly Galinsky | Lectorium

Subtitles

Application

Three-dimensional graphics are actively used to create images on a screen plane or a sheet of printed materials in science and industry, for example, in design automation systems (CAD; for creating solid elements: buildings, machine parts, mechanisms), architectural visualization (this also includes the so-called “virtual archeology”), in modern medical visualization systems.

The widest use is in many modern computer games, as well as as an element of cinema, television, and printed products.

Three-dimensional graphics usually deals with virtual, imaginary three-dimensional space that is displayed on a flat, two-dimensional surface of a display or sheet of paper. Currently, several methods are known for displaying three-dimensional information in volumetric form, although most of them represent volumetric characteristics very conditionally, since they work with a stereo image. From this area we can note stereo glasses, virtual helmets, 3D displays capable of demonstrating a three-dimensional image. Several manufacturers have demonstrated production-ready 3D displays. However, 3D displays still do not allow the creation of a full-fledged physical, tangible copy of the mathematical model created by three-dimensional graphics methods. Rapid prototyping technologies that have been developing since the 1990s are closing this gap. It should be noted that rapid prototyping technologies use a representation of the mathematical model of an object in the form of a solid body (voxel model).

Creation

To obtain a three-dimensional image on a plane, the following steps are required:

• modeling- creation of a three-dimensional mathematical model of the scene and objects in it;
• texturing- assigning raster or procedural textures to model surfaces (also implies setting material properties - transparency, reflections, roughness, etc.);
• lighting- installation and configuration;
• animation(in some cases) - giving movement to objects;
• dynamic simulation(in some cases) - automatic calculation of the interaction of particles, hard/soft bodies, etc. with simulated forces of gravity, wind, buoyancy, etc., as well as with each other;
• rendering(visualization) - construction of a projection in accordance with the selected physical model;
• compositing(layout) - image refinement;
• output the resulting image to an output device - a display or a special printer.

Modeling

The most popular packages purely for modeling are:

• Robert McNeel & Assoc. Rhinoceros 3D ;

To create a three-dimensional model of a person or creature, Sculpture can be used as a prototype (in most cases).

Texturing

SketchUp

Visualization of 3D graphics in games and applications

There are a number of software libraries for visualizing 3D graphics in application programs - DirectX, OpenGL and so on.

There are a number of approaches to presenting 3D graphics in games - full 3D, pseudo-3D.

Such packages do not even always allow the user to operate the 3D model directly; for example, there is the OpenSCAD package, the model in which is formed by executing a user-generated script written in a specialized language.

3D displays

Three-dimensional or stereoscopic displays, (3D displays, 3D screens) - displays that, through stereoscopic or some other effect, create the illusion of real volume in the displayed images.

Currently, the vast majority of three-dimensional images are displayed using the stereoscopic effect, as it is the easiest to implement, although the use of stereoscopy alone cannot be called sufficient for three-dimensional perception. The human eye, both in pairs and alone, distinguishes three-dimensional objects from flat images equally well [ ] .

Three-dimensional graphics today have become so firmly established in our lives that sometimes we don’t even pay attention to its manifestations.

Looking at a billboard depicting the interior of a room or an advertising video about ice cream, watching the frames of an action-packed film, we have no idea that behind all this lies the painstaking work of a 3D graphics master.

3D graphics is

3D graphics (three-dimensional graphics)- this is a special type of computer graphics - a set of methods and tools used to create images of 3D objects (three-dimensional objects).

A 3D image is not difficult to distinguish from a two-dimensional one, since it involves creating a geometric projection of a 3D model of the scene onto a plane using specialized software products. The resulting model can be an object from reality, for example a model of a house, car, comet, or it can be completely abstract. The process of constructing such a three-dimensional model is called and is aimed, first of all, at creating a visual three-dimensional image of the modeled object.

Today, based on 3D graphics, you can create a highly accurate copy of a real object, create something new, and bring the most unrealistic design ideas to life.

3D graphics technologies and 3D printing technologies have penetrated into many areas of human activity and bring enormous profits.

3D images bombard us every day on television, in movies, while working with computers and in 3D games, from billboards, clearly representing the power and achievements of 3D graphics.

The achievements of modern 3D graphics are used in the following industries

1. Cinematography and animation- creation of three-dimensional characters and realistic special effects . Creation of computer games- development of 3D characters, virtual reality environments, 3D objects for games.
2. Advertising- the capabilities of 3D graphics allow you to advantageously present a product to the market; using 3D graphics you can create the illusion of a crystal-white shirt or delicious fruit ice cream with chocolate chips, etc. At the same time, in reality, the advertised product may have many shortcomings that are easily hidden behind beautiful and high-quality images.
3. Interior design- design and development of interior design also cannot do without three-dimensional graphics today. 3D technologies make it possible to create realistic 3D models of furniture (sofa, armchair, chair, chest of drawers, etc.), accurately repeating the geometry of the object and creating an imitation of the material. Using 3D graphics, you can create a video showing all the floors of the designed building, which may not even have started construction yet.

Steps to create a 3D image

In order to obtain a 3D image of an object, you must complete the following steps

1. Modeling- construction of a mathematical 3D model of the general scene and its objects.
2. Texturing includes applying textures to created models, adjusting materials and making models look realistic.
3. Lighting settings.
4. (moving objects).
5. Rendering- the process of creating an image of an object using a previously created model.
6. Compositing or compositing- post-processing of the resulting image.

Modeling- creation of virtual space and objects within it, includes the creation of various geometries, materials, light sources, virtual cameras, additional special effects.

The most common software products for 3D modeling are: Autodesk 3D max, Pixologic Zbrush, Blender.

Texturing is an overlay on the surface of a created three-dimensional model of a raster or vector image that allows you to display the properties and material of an object.

Lighting- creation, direction setting and adjustment of lighting sources in the created scene. Graphic 3D editors, as a rule, use the following types of light sources: spot light (divergent rays), omni light (omnidirectional light), directional light (parallel rays), etc. Some editors make it possible to create a volumetric glow source (Sphere light).

3D graphics is the process of creating a three-dimensional model using special computer programs. This type of computer graphics has absorbed a lot from vector, as well as raster computer graphics. Based on drawings, drawings, detailed descriptions or any other graphic or text information, a 3D designer creates a three-dimensional image.

In a special program, the model can be viewed from all sides (top, bottom, side), built into any plane and into any environment. Three-dimensional computer graphics, like vector ones, are object-oriented, which allows you to change both all elements of a three-dimensional scene, as well as each object individually. This type of computer graphics has great potential to support technical drawing. Using graphic editors of three-dimensional computer graphics, you can create visual images of parts and mechanical engineering products, as well as perform prototyping of buildings and architectural objects studied in the corresponding section of architectural and construction drawing. Along with this, graphic support can be provided for such sections of descriptive geometry as perspective, axonometric and orthogonal projections, because the principles of constructing images in three-dimensional computer graphics are partially borrowed from them.

Three-dimensional graphics can be of any complexity. You can create a simple 3D model, with low detail and a simplified shape. Or it could be a more complex model, in which the smallest details, textures are worked out, professional techniques are used (shadows, reflections, light refraction, and so on). Of course, this seriously affects the cost of the finished 3D model, but it allows you to expand the use of the 3D model.

Where is 3D graphics used?

Three-dimensional modeling (3D graphics) is used today in many areas. Of course, first of all, this is construction. This could be a model of a future home, either a private, apartment or office building, or indeed any industrial facility. In addition, visualization is actively used in interior design projects.

3D models are very popular in website development. To create a special effect, some website creators add not just graphic elements to the design, but three-dimensional models, sometimes even animated. Three-dimensional modeling programs and technologies are widely used in manufacturing, for example, in the production of cabinet furniture, and in construction, for example, to create a photorealistic design project for a future room. Many designers have long moved from using a ruler and pencil to modern three-dimensional computer programs. Gradually, other companies, primarily manufacturing and trading ones, are mastering new technologies.

Of course, 3D models are mainly used for demonstration purposes. They are indispensable for presentations, exhibitions, and are also used in working with clients when it is necessary to clearly show what the final result will be. In addition, three-dimensional modeling methods are needed where it is necessary to show in volume already finished objects or those objects that existed once upon a time. 3D modeling is not only the future, but also the past and present.

Benefits of 3D Modeling

3D modeling has many advantages over other visualization methods. Three-dimensional modeling provides a very accurate model that is as close to reality as possible. Modern programs help achieve high detail. At the same time, the visibility of the project increases significantly. Expressing a three-dimensional object in a two-dimensional plane is not easy, while 3D visualization makes it possible to carefully work out and, most importantly, view all the details. This is a more natural way of visualization.

It is very easy to make almost any changes to the 3D model. You can change the project, remove some parts and add new ones. Your imagination is practically unlimited, and you can quickly choose the option that suits you best.

However, 3D modeling is not only convenient for the client. Professional programs provide many benefits to the manufacturer as well. From a three-dimensional model you can easily extract a drawing of any components or the entire structure. Despite the fact that creating a three-dimensional model is a rather labor-intensive process, working with it in the future is much easier and more convenient than with traditional drawings. As a result, design time is significantly reduced and costs are reduced.

Dedicated programs allow integration with any other professional software, such as engineering applications, machine tools or accounting programs. The implementation of such solutions in production provides significant savings in resources, significantly expands the capabilities of the enterprise, simplifies work and improves its quality.

3D modeling software

There are quite a large number of different programs for 3D modeling. Thus, one of the popular programs that are specially designed for creating three-dimensional graphics and interior design is the 3D Studio MAX program. It allows you to realistically visualize objects of varying complexity. In addition, “3D Studio MAX” makes it possible to compose them, set movement trajectories and, ultimately, even create a full-fledged video involving three-dimensional models. Although such work, of course, requires a specialist to have serious skills, as well as large computer resources, primarily memory and processor speed.

The Maya editor is named after the Sanskrit word that means illusion. Maya was developed by Alias ​​Systems. In October 2005, Alias ​​merged with Autodesk. Maya is more commonly used to create animation and 3D effects in films.