# 3D Modelling

## Summary


A 3D model is a geometric representation of an object or a surface in a simulated 3D space. 3D modelling is about creating such models using computer software. Designers design completely new models or feed scanned images of existing objects into the computer to create 3D models. 

3D modelling is an art. It enables one to visualize the final output before building it. It also allows model derivations for detailed viewing. 

3D modelling is the bedrock of 3D printing. It evolved with the 3D printing industry that grew big in the 1990s. Almost every industry uses 3D modelling in some form. Video game development, filmmaking, architecture and engineering industries actively employ 3D modelling. It offers vital support for Industry 4.0 technologies to achieve a fully immersive interactive experience in virtual environments. Forecasts suggest the 3D modelling market will touch $7.6 billion by 2025.

## Discussion

### How is 3D modelling put to use?

The crux of 3D modelling is visualization and creativity. Modellers can create 3D models of a person, atmosphere or object of their choice. Using 3D modelling, one can easily understand complex designs. It allows modellers to fix drawing errors quickly. Modellers can design data-based models quite accurately. 

Different modellers use 3D modelling for different purposes. Engineers and designers use it to design new products or redesign existing products. Architects build visual demonstrations of buildings, landscapes and interiors using 3D modelling. Animation and game designers use it to create digital characters and assets. Filmmakers use it to produce visual effects. 

Medical industries 3D model designs for manufacturing prosthetics, dental implants and medicines. 

3D modelling offers cutaway visualization, surface curvature measurement and multispectral analysis. These are techniques to engage with materials in academic fields. 

Additive manufacturing technologies use 3D modelling to construct models for 3D printing or manufacturing items in layers. 

Augmented Reality (AR) and Virtual Reality (VR) developers apply 3D modelling to add a sense of reality to the non-existent realities they create. 


### Can you discuss some important types of 3D modelling?

**Solid Modelling** drafts models with simple shapes such as spheres, cubes and prisms. It suits best for models involving flat surfaces and simple curves of constant radii. It produces mathematically correct final outputs. 

**Wireframe Modelling** stitches the vertices of shapes in a web to make models. Each shape will have three or more vertices. So the web is a network of polygons. The triangle is its smallest polygon. The higher the number of triangles, the closer the 3D model will be to realism.  

**Surface Modelling** follows guiding lines to define the shape and curvature of a 3D part. Software tools estimate the smooth surfaces and connect these guiding lines. Surface modelling handles complex shapes. It can produce visuals impossible to replicate in the real world.    

Some other important methods are *Polygonal Modelling*, *Sculpting*, *Box Modelling*, *Non-Uniform Rational Basis Spline (NURBS)*, and *Non-Uniform Rational Mesh Smooth (NURMS)*. 

Modellers may convert wireframe models into 3D views and add surfaces. It takes specific modelling operations. For example, *Boolean Operations* help to combine objects, subtract objects and create intersections. *Parametric Modelling* is the best fit to create design intent between dimensions, parts and assemblies. 


### Can you describe the typical workflow of 3D modelling?

3D modelling starts with conception. Designers use reference images, real-world objects or existing concepts to conceive a model output.  

Planning for execution is the next step. The main idea is to fix the model's geometry, proportions and shapes before jumping in.  

In the execution stage, 3D modellers or artists use software to create primitive shapes that conform to the planned design. These shapes may not serve their best interests yet. So they add details to refine the design. And the model so refined will be of high polygon count. 

Since high-poly models are unsuitable for animation, modellers do a retopology on them. *Retopology* means simplifying complex models by reducing their polygon count. Low-poly models will need texturing. *Texturing* includes applying colours, textures, and material attributes to the surface of the 3D model. Put another way, texturing clothes the 3D model with 2D images called *Texture Maps*. Modellers consider how lights hitting on the 3D object's surface reflect its colour and surface texture. 


### What are some 3D modelling terms you need to know?

We note a few essential terms:

    + **3D**: The three spatial dimensions are width, height and depth.
    + **Axis of motion**: It's the imaginary line an object follows in a 3D space.
    + **Axis of rotation**: It's the line in a 3D space about which an object rotates.
    + **Beveling**: Modifying the edges of the 3D objects under design is beveling. It adds a hint of realism to the models.
    + **Extrusion**: An extrusion tool creates 3D objects by forcing a third dimension on a two-dimensional model.
    + **Nodes**: Nodes in 3D modelling are software functionalities packaged into atomic units. Nodes organized in a 3D environment are called node graphs. Modellers manipulate these node graphs via programmable APIs or visual interfaces by hovering a mouse. For instance, a *rotate node* produces rotated 3D textures. Similarly, a *pattern node* mixes patterns to form patterned textures.
    + **Sculpting**: Modellers sculpt objects on a 3D display using software tools. They perform operations such as pushing, pulling, pinching, and grabbing to manipulate shapes.

### What are some hardware considerations for 3D modelling?

Due to rendering, not every computer can perform 3D modelling efficiently. Rendering adds specifications and design enhancements to yield presentable finished model. It requires hardware that can handle intense graphics and heavy software applications.  

Some general component requirements are:

    + **Central Processing Unit (CPU)**: Select multiple cores if you need rendering. A single core would be sufficient if you are happy with 3D modelling alone.
    + **Graphics Processing Unit (GPU)**: It processes graphics and complex calculations. It gives good quality outputs and consumes less processing time. Opt for a GPU that suits you best. Currently, NVIDIA GTX 1060 or higher graphics in the NVIDIA series works best for modelling.
    + **Random Access Memory (RAM)**: Ensure you have at least 8GB for smooth operations.
    + **Hard Disk Storage**: Storage capacity will depend on the project size. However, adding a Solid State Device (SSD) storage boosts performance speeds.Apart from these, a monitor, a computer case, a power supply, cooling systems and other peripherals are essential. If the minimum requirements are not met, your system might work slowly. It may even freeze or crash. Overall, it will hamper productivity and frustrate you. 


### What are the software applications required for 3D Modelling?

3D modelling involves the following software:

    + **Platform**: We need a browser or an operating system (OS) to run 3D software applications. The OS requirements differ for different file formats and use cases. Most software applications run on top of Windows, macOS, iOS, Linux, or Android.
    + **Specialized Software Applications**: For example, Tinkercad, Meshmixer, and SketcUP Free specialize in direct modelling. SculpGL, Leopoly and ZbrushCoreMini are useful for sculpting. Vectary is good for mesh modelling and parametric modelling. Blender specializes in sculpting.
    + **Extension System**: Designers store 3D designs in standard file formats such as STL, IGS and OBJ. Devices compatible with these formats can access the designs.
    + **Component Library**: This feature offers a single source of truth to store and retrieve design components. It lends consistency to designers working on the same project. Design developers who prefer code components to images will find it helpful.


## Milestones

1963

Ivan Sutherland develops and releases the first 3D drawing software called Sketchpad. It runs on a Lincoln TX-2 machine designed in 1956. Sketchpad becomes a pioneering contributor in the Human-Computer Interaction (HCI) field. It's a forerunner of the CAD software that we use today. It later plays an important role towards the development of Computer Graphics (CG). Graphic designers use sophisticated object-oriented programming (OOP) and Sketchpad to create Graphic User Interfaces (GUIs). 

1964

IBM and General Motors join hands to develop DAC-1 (Design Augmented by Computer). It speeds up car production and provides quick and good-quality visualization. 

1971

Donald P. Greenberg produces an early, sophisticated CG movie at the General Electric Visual Simulation Laboratory. He calls it Cornell in Perspective.  Elsewhere, Dr Patrick J. Hanratty designs and introduces Automated Drafting And Machining (ADAM). It's a CAD software application. His company, Manufacturing and Consulting Services (MCS), supplies CAD software to major companies of the time, such as McDonnell Douglas. 

1974

Donald P Greenberg founds the Program of Computer Graphics (PCG) at Cornell University, New York. Greenberg's later works become foundational for many of the Computer Graphics applications in the market today. 

1975

Dr Kenneth Versprille introduces Non-Uniform Rational B-Splines (NURBS) to CAD while working under ComputerVision. NURBS finds wide application in later years. 

1980

The U.S. National Bureau of Standards introduces Initial Graphics Exchange Specification (IGES). It becomes the standard file format to move CAD files between different software. STEP replaces it in 1994. 

1982

John Walker founds Autodesk inc and introduces AutoCAD for computers. It's a handy tool for Architects and Engineers. AutoCAD would later introduce a 3D design that combines CAD tools and Building Information Modelling (BIM) for simulation and visualization. 

1988

Martin Newell designs Cobalt (CAD Program). It's an early parameter-based CAD program and 3D modelling. It runs on both Macintosh and Microsoft Windows Operating Systems. 

1992

Juergen Heimbach sets up Cadenas, an engineering firm that provides software solutions to 3D models. Cadenas' digital catalogues permit access to component information from anywhere in the world. 

1994

ISO Standard for the Exchange of Product Data (STEP) takes over as the new format for exchanging 3D data. It's a widely accepted international standard. STEP file is also addressed as ISO 10303-11. 

1995

MIT Blackjack member, Jon Hirschtick, launches SolidWorks. It's a 3D CAD software that works on Windows platforms. It's easy to use and affordable. 

2010

Autodesk releases AutoCAD 360. It's the mobile version of AutoCAD that enables designers to work from anywhere. 

2012

Autodesk moves CAD to Cloud. Cloud enables several teams to work on the same design simultaneously. 

2015

Mindesk's co-founder, Gabriele Sorento, presents a prototype that facilitates a Virtual Reality (VR) Interface for CAD software. 

2019

Autodesk releases CAD to AR inventor app. It permits the view of inventor models in Augmented Reality (AR).