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Rendering in 3D

A Photorealistic 3D Rendering
A Photorealistic 3D Rendering

Following on from our previous articles on the 3D Modelling, lighting, materials and textures and animation we now finish our 5 part series with a look at 3D Rendering.

In 3D graphics rendering means the calculation of the final image from the scene that includes models, textures, lights, special effects and cameras. The final image will be a 2D image made of pixels. Utilizing materials, lighting techniques, and renderer's settings one can render multitude of different images from a single 3D scene. Often the goal is to produce realistic rendering, for example in live action movies the goal is to render 3D effects as realistically as possible as it is a cheaper and easier alternative to building sets or hiring extras for a scene.

Photo Realistic Rendering:

Photo Realistic Render of 3D Diamonds
Photo Realistic Render of 3D Diamonds

With technology continuing to improve at a rapid rate renders from 3D sofwares are becoming more and more realistic. The ability to apply and map bitmap texture images is a big part of this realism but the key to real photo realism is generally attention to detail when lighting the scene but lighting a scene realistically is also one of the most challenging aspects of producing photo realistic renderings. If you haven't already, please see the article of the basics of 3D lighting types to help you get started.

Clay Model Rendering:

A Clay Render of a 3D Model
A Clay Render of a 3D Model

When 3D modeler's present their modelling skills they often produce a clay render. Clay render means a rendering which looks like a picture of a clay model. The idea of a clay render is to bring out the form of the model. This is not really a rendered effect however as it is generally the default form of a non textured model or a model without materials. However good lighting is necessary to effectively showcase a model in a clay style render.

Wireframe Rendering:

 A Wireframe Render of a 3D Model
A wireframe Render of a 3D Model

The purpose of wire rendering is to reveal the polygon structure of the model. Wire rendering displays only edges of the polygons. Wire render and clay render are often combined.

Cell Shading / NPR Rendering:

A Cell Shading Render
A Cell Shading Render

Cell Shading is a from of Non-photo realistic rendering (NPR). In contrast to traditional computer graphics, which has focused on photo realism, NPR is inspired by artistic styles such as painting, drawing, technical illustration, and animated cartoons and focuses on enabling a wide variety of expressive styles for digital art. NPR has appeared in movies and video games in the form of "cartoon shading", as well as in architectural illustration and experimental animation.

An example of a modern use of NPR is that of cell-shaded animation as seen above. Another form of NPR is cartoon style rendering means a material / rendering method that produces an image that looks like a hand drawn picture.

In order to test out some of these rendering techniques for yourself have at look at these free 3D Modelling Softwares.

Basics of 3D Animation

3D Character Animation
3D Character Animation
Following on from our previous articles on the basics of 3D Modelling, the basics of 3D lighting and 3D materials and textures we now continue on to look at the basics of 3D Animation.

Computer animation is essentially a digital successor to the stop motion techniques used in traditional animation with 3D models and frame-by-frame animation of 2D illustrations. 3D animations are more controllable than other more physically based processes, such as constructing miniatures for effects shots or hiring extras for crowd scenes, and because it allows the creation of images that would not be feasible using any other technology. It can also allow a single graphic artist to produce such content without the use of actors, expensive set pieces, or props.
Creation of 3D character animation is a very complicated process which consists of four separate steps:
  • Modelling the character
  • Rigging the character
  • Skinning the character
  • Animating the character

Modelling the character

Views of a 3D Character Model
Views of a 3D Character Model
A character, especially a realistic one is one of the most challenging subjects to model believably. If a character is going to be animated, the task is even more challenging. When creating 3D models which are going to be deformed (such as a human hand), one must be extra careful when defining the structure of the surface. The structure (orientation and type of polygons) of the 3D model defines how well it is suited for an animation.

Rigging the character

3d character rigging
3D Character Rigging
Character rigging means a process of creating the bone structure for a character. The bone structure is a set of helper objects that correspond to bones in real life. The bones (helper objects) will be animated and the character will move and deform accordingly. Bones itself won't show in the final rendered image.

Skinning the character

Skinning a 3D Character Model
Skinning a 3D Character Model
Character skinning means the process of defining how exactly the character responds to the movement of the bones. In the skinning process one goes through all the joints in the bone structure and carefully adjusts how the 3D model deforms while a certain bone is moving. As an addition to bones there are also other special tools and modifiers designed to help in character animation. For example facial animation is often carried out by morphing the face between several predefined states.

Animating the character

The last step in character animation is the animating itself. Animating requires a lot of skill and practice. An animator should understand at least the basics of character movement such as the concept of anticipation. Character animation process can be fluid when rigging and skinning are done with care.

For 3D animations, objects are modelled and 3D figures are rigged with a virtual skeleton. Then the limbs, eyes, mouth, clothes, etc. of the figure are moved by the animator on key frames. The differences in appearance between key frames are automatically calculated by the computer in a process known as tweening or morphing. Finally, the animation is rendered.

For 3D animations, all frames must be rendered after the modelling is complete. For pre-recorded presentations, the rendered frames are transferred to a different format or medium, such as film or digital video. The frames may also be rendered in real time as they are presented to the end-user audience.

The samples in this articles are all from the free 3D modelling software Blender but before you decide which 3D Modelling software is best for you have at look at this articel which reviews and rates the best free 3D Modelling Software.

Next up in the 3D Modelling and Animation series is the final stage, 3D Rendering.