Talking about 3D Modeling Technology

Abstract: Three-dimensional modeling technology is the key part of three-dimensional film and television animation, and it is also the basis for the success of film and television animation. In 3D,

There are basically two kinds of objects: regular objects and irregular objects. The modeling process begins with structural analysis, and when we face it,

When creating a composite object, the existing geometry provided by software can be used to set its general shape, and the details can

Further processing, this idea is similar to the composition of the picture painted in the early stage of painting. In three-dimensional movies and TV animations

The main three-dimensional modeling methods are polygon modeling, non-uniform rational B-spline curve modeling and subdivision surface technology modeling.

[Keywords:] 3D modeling technology of film and television animation

1, Introduction

Before talking about 3D modeling, let's take a look at us.

The big environment of times life is like living in the movie "The Matrix".

Like junior high school, nothing is digitized.

Traces, things around us, such as newspapers, magazines, movies and television.

CDs, video games, even every TV advertisement, every one.

Posters and posters are all processed by computer images.

Although computer graphics has experienced a long time of development, but look

I have seen a lot of stereoscopic things for almost ten years. exist

In today's movies, 3D also plays an increasingly important role.

In China, it took IDMT four years to build a pure three-dimensional electricity.

The film Mobius Ring is a successful example. Film and television animation

This is especially true in movies and movie stunts.

Using three-dimensional animation technology, from Star Wars and refers to

Special effects production of thousands of shots in The Lord of the Rings, to Toys Always Move.

Member, stray rat country and Shrek are pure three-dimensional electricity.

The birth of film and the application of 3D have become the whole film and television industry.

A box office weapon, the domestic film Hero relies on its Excellence.

Three-dimensional special effects technology ranked first at the box office in North America for two weeks in a row, which

There are countless movies that can be listed in the movie.

The position of modeling in 3D is undoubtedly heavy.

Want it. Model is the carrier of material, and it is a pair of lighting and rendering.

Elephants are the masters of the 3D world. However, modeling is still far from 3D.

All of them, especially the movie special effects, some shots.

There is no trace of the model at all, which is a success for the film.

Yes, it means that the special effects fooled the audience's eyes. As a modeler,

There is no need to feel lost because of this, because its special effect is also

Is based on the right model. [ 1]

2. Object classification in 3D movie animation.

There are basically two kinds of objects in 3D: regular objects and.

Irregular objects. In 3D software, the shapes of objects can be communicated.

Described by some morphological rules, it has obvious characteristics in appearance.

Objects that can be accurately reproduced belong to regular objects. compare

Such as buildings, vehicles and boats, household appliances, etc. , these objects are controlled.

Grid has clear indicators, so it can be mass-produced, 3D.

It's called cloning. As a matter of common sense, one of the two modes

It is not surprising that exactly the same rule objects are put together. no

Details and even shapes of regular objects are arbitrary.

Mountain landforms, plants, animals and astronomical phenomena change endlessly.

For the same reason, when making three-dimensional objects,

The principle of artificial modification to make it natural is

It's impossible.

What is the practical significance of this classification? Because both

The production of animation models is very different.

General objects can be different according to standards.

People can make the same result, the difference of production level.

It all depends on the author's production time. Irregular object

There is no unique standard, how vivid and natural depends on the work.

The author's understanding of three-dimensional objects depends on the producer's experience and understanding.

Make love. Therefore, the production of this model is particularly challenging.

Ability. Take the most typical role modeling in biological modeling for example.

It is said that the most basic requirement is anatomical knowledge, not muscle.

And the basic principles of bones. And aesthetics.

The basic form, the proportion of characters should be appropriate, and all parts should have it.

A sense of wholeness. These requirements themselves cannot be quantified because

It is not a regular object, so it is difficult to learn.

Yes Plants are stranger than people we are familiar with and their rules.

The law seems to be traceable, but in fact it is chaotic. Put forward such a question

Materials, but also a lot of observation and research and calculation of it, which

It is no longer a simple 3D work.

3. The relationship between painting structure analysis and three-dimensional modeling.

The process of modeling begins with structural analysis, and when we face it,

For a composite object, you can first imagine what bases it has.

This geometry, maybe we can use software.

Set the general shape and details of the existing geometry.

Part can be further processed. This kind of thinking and the early stage of painting

The composition of the sketch is similar. Sketch structure line

The most important thing to pay attention to in the early stage is the direction of 3D model.

Things. However, for an experienced modeler, he doesn't.

Always analyze objects from head to toe like this, and

Will get involved in the details as quickly as possible according to their own habits, but

However, apart from the speed advantage, this practice may be difficult to guarantee.

It is proved that the grid layout is reasonable and the overall structure is accurate. In this way,

Sometimes I will rework, and sometimes I will stay in a tricky position.

Link, but it affects the speed. For strange objects, you must not

Don't reanalyze the structure. So, for a successful

As a modeler, he has excellent analytical ability and summary ability.

Ability is crucial. When we are as careful as painting

Observe the object carefully and make a reasonable judgment, and model it into one.

This is a simple and interesting job.

4. 3D modeling method in 3D movie animation.

Three-dimensional modeling methods in three-dimensional movie animation mainly include polygon modeling and non-uniform rational B-spline curve.

Modeling (NURBS), subdivision surface technology modeling (subdivision

Surface). Generally, models can be established by several methods.

There are two ways to obtain, but each has its advantages and disadvantages and simplification.

4. 1 polygon modeling

Polygon modeling is suitable for creating shape specifications.

Then, an object without a surface. With polygon modeling, you can first create

Basic geometry, and then use edit modifiers as needed.

The whole object shape, or through Boolean operation, lofting, surface patches.

The main advantage of polygon modeling is that it combines objects to build objects.

It is simple, convenient and fast, but it is difficult to generate smooth surfaces. correct

To create a good model with polygons, you can also adjust it.

Modeling parameters, obtaining models with different resolutions to adapt to virtual.

The requirements of real-time display of simulated scenes.

4.2NURBS modeling

NURBS is non-uniform and rational.

Abbreviation for B-spline (non-uniform rational B-spline curve),

It is purely a mathematical concept of computer graphics.

NURBS modeling technology is a three-dimensional movie animation that appears in recent years.

One of the most important modeling methods, especially suitable for creating smoothness.

Complex model, as well as universality and modeling in application.

The fidelity of details is unmatched by other technologies.

Advantage. However, NURBS modeling must use patches.

As its basic modeling unit, it also has the following limitations.

Properties: NURBS surfaces have only a limited number of topological structures and derivatives.

It is difficult to manufacture objects (such as belts) with complex topologies.

Empty object); The basic structure of NURBS surface patch is mesh.

Lattice, if the model is complex, will lead to sharp control points.

Increasing and uncontrollable, it is difficult for NURBS to construct "with branches"

"against it.

4.3 subdivision surface technology

Subdivision surface technology is a three-dimensional building introduced by 1998.

Modular method solves the problem of creating surface by NURBS technology.

In the face of difficulties, arbitrary polyhedron is used as the control network.

Grid, and then automatically generate a smooth song according to the control grid.

noodle The mesh of subdivision surface technology can be any shape, because

But you can easily build various topologies and always

Keeping the smoothness of the whole surface is another technique to subdivide the surface.

An important feature is "subdivision", that is, it only increases locally in the object.

Add details without increasing the complexity of the whole object.

While maintaining the smoothness of the object with added details. [2]