Єгошкін Д. І., Хижа О. Л., Комарова Л. В.

Дніпропетровський національний університет імені Олеся Гончара

KEY POINTS IN THE 3D MODELING

The development of computer technology and hardware improvements have allowed us to create sophisticated and at the same time effective programs. In this regard, the IT industry has increased sharply, which allowed to develop computing business in different directions. These factors gave us 3D graphics and the notion of 3D technology. In this report you will immerse into 3D graphics world.

What does 3D mean? It is 3 Dimensional, in other words we show the object in three parameters, which are: width, length, and depth. Look around, and you can see that everything is three-dimensional (walls, chairs, people, animals etc.). While working in the 3D programs, static and dynamic scenes are created as a result of long work. Static scene is the definite collection of geometric objects – flat and volumetric. They are three-dimensional, that is described by three coordinates x, y, z. Dynamic scenes are described by the new parameter – time. And "image" is a result of the work on static three-dimensional scene. The output of dynamic scene is a set of "pictures" or animation sequence depending on the time.

History. The phrase “Computer Graphics” was coined in 1960 by William Fetter, a graphic designer for Boeing. In 1960-1969 Many scientists have been developing their projects towards 3D graphics: Ivan Sutherland (1961 – created program called Sketchpad), Steve Russell (1961-created the first video game, Spacewar), E. E. Zajac( created a film called "Simulation of a two-giro gravity attitude control system" in 1963 ), Ralph Baer (came up with a home video game in 1966 that was later licensed to Magnavox and called the Odyssey) and many others. It was a big step into the Digital future.

Where we use 3D graphics? Today, 3D graphics are evolving very fast and have a lot of ways of their implementation. In medicine they are used to create 3D models of bones, skull, teeth, etc. It is need for recovery of injured tissue. In architecture 3D graphics are used to create accurate drawing and show the preview of future building [1]. It is also used in car, furniture modeling and other branches which need accurate drawings. In car modeling it helps to configure machine-tools which create finished car body.

And finally today 3D graphics evolving very fast in greatest branches which gave it a life. This branches are cinema, games, cartoons, and 3D cinema like IMAX 3D. In 1976 one of the first computer animation displays was “Futureworld”, which included an animation of a human face and a hand —produced by Ed Catmull and Fred Parke at the University of California. Than in 1974 Lucas gathered the best engineers, programmers, mathematicians and other different professionals. With their help, he created a huge center for special effects. He has created film which turned the representation about 3D graphics and opened its full potential. In 1977 the film was released in movie theatres. It was “Star Wars“.

The key point in the 3D modelling is the algorithm. Tjomin G. [4] considered the algorithm which consists of four steps. After my study of many programs (3Ds max Studio, Autodesk Maya, Zbrush, Autodesk Mudbox, Xfrog, MindAvenue AXELedge, Blender) the new algorithm was created.

In this work we suggest to consider the algorithm which consists of 13steps.

1. Computation of geometry that means when you want to create some model you must know your computer System Requirements. Preceding from this you can calculate how many points, ribs and faces you can control without overloading of your computer. It will help you in future when you start to move or modify your model. In this section you also the paper drawing of your future model is needed. It should look like carcass of ribs. If your model has point where it will be moving or modifying you should improve its mesh in this point.

2. Type of geometry. At first you need to choose type of geometry the segment or wire-frame model. Segment model consists of standard primitive objects (cube, sphere, etc.). This type of modeling is used to create very simple model which don’t overload computer. Wire-frame model looks like carcass of ribs. Wire-frame type is used to create high detailed model.

3. Method of creating geometry. In 3D programs you can create model by any mean. It can be: line, plane, NURBS (non-uniform rational B-spline), standard primitive objects (cube, sphere, etc.). Line and NURBS are basically used to create figure of rotation and also to create wire-frame model.

4. Creating Geometry. Having known how many points, ribs and faces you can control and viewing your future mesh. You can start to work with software. Everything starts from simple geometric objects – flat and volumetric. And then you need to modify it until you get what you need. Sometimes you need to merge a few objects working with very difficult models.

5. Create UVW unwrapping texture. UVW mapping is a mathematical technique for coordinate mapping. "UVW", like the standard Cartesian coordinate system, has three dimensions; the third dimension allows texture maps to wrap in complex ways onto irregular surfaces. In 3D program you can convert your model in UVW map and then repaint map and upload it back.

6. Texturing and overlay maps. Having created your 3D model you need to give it a color. For realistic models it is main part because it gives life picture. If you think that you need only one map I have to disappoint you because you also need diffuse map, opacity map, bump map, reflection map, glossiness map, specular map and others. It will help you to create a very realistic model.

7. Creation of the skeleton. In in this part you should count the place where your model will bend. On this basis you can create a skeleton for your model. Skeleton is made up of simple objects and hierarchical linking.

8. Setting up the skeleton. Move the skeleton inside a mesh model. Then set up the skeleton using the program which thinks that the mesh of a model is skin and gives each bone of skeleton a weight. (Weight – control area of points on mesh).

9. Muscles. Now when you set up skeleton you should create the muscles. It will help you to deform your model properly. It also creates a realistic bending and realistic model of a physical structure [2].

10. Rigging. In this part we will use a script language. We use it to create a link with slider or control panel. It also is used to create a new hierarchical linking. It will help you to control all bones of skeleton and simplify your work in animation.

11. Debugging lights, film cameras. You should set up lights and film cameras. Lights will help you to show your model in a good light. It is also used to create the atmosphere and environment effects like sun rings, sun light, create shadows and etc. Film cameras will help you to capture your model and then render (visualize) it.

12. Custom Animation. In this section you start to move your model or bones of skeleton and set the animation keys. Any 3D program has animation graphics which show motion of objects on the axes. You should always watch for it.

13. Visualization. Any 3D program has a built-in-visualizer. When you finished your work you need to see the result. Visualizer will help you. But you need to choose the quality of image or video, choose bit rate, format, stream size, color space, display aspect ratio, frame rate and etc. in 3D programs visualizer, also called the Render.

The suggested algorithm helped us to create: 1) The items7,8,10 are not needed for creation the realistic facial animation; 2) The items7,8,9,10 are not needed for creation the rain animation; 3) To create an animation of the character’s movements all the points have been used.

Review of 3D modeling done in this study revealed the presence of a typical algorithm for constructing 3D models. Algorithm which develops 3D modeling includes 13 points. The developed algorithm is used to create static and dynamic scenes. The obtained result is the following:1) files which describe the geometry; 2) the frame or sequence of them.

The list of references:

1. Web resource. – Access mode: http://www.autodesk.com/products/ autodesk-autocad-architecture/overview

2. Web resource. – Access mode: http://area.autodesk.com/tutorials-tips

3. Kelly L. Murdock 3ds Max 2010 Bible / L. Kelly. – Wiley Publishing, 2009. – 1312 p.

4. Темин Г. 3D Studio Max 5. Эффективный самоучитель / Г. Темин. – Diasoft, 2003. – 464 с.