computer science

Wire-frame model

Wire-frame model is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Wire-frame model rather than just read about it. In short: In 3D computer graphics, a wire-frame model (also spelled wireframe model) is a visual representation of a three-dimensional (3D) physical object. It is based on a polygon mesh or a volumetric mesh, created by specifying each edge of the physical object where two mathematically continuous smooth surfaces meet, or by connecting an object's constituent vertices using (straight) lines or curves.

Key takeaways

Wire-frame model belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Wire-frame model to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Wire-frame model from memory before moving on to harder problems.

Reference excerpt

In 3D computer graphics, a wire-frame model (also spelled wireframe model) is a visual representation of a three-dimensional (3D) physical object. It is based on a polygon mesh or a volumetric mesh, created by specifying each edge of the physical object where two mathematically continuous smooth surfaces meet, or by connecting an object's constituent vertices using (straight) lines or curves. The object is projected into screen space and rendered by drawing lines at the location of each edge. The term "wire frame" comes from designers using metal wire to represent the three-dimensional shape of solid objects. 3D wireframe computer models allow for the construction and manipulation of solids and solid surfaces. 3D solid modeling efficiently draws higher quality representations of solids than conventional line drawing. Using a wire-frame model allows for the visualization of the underlying design structure of a 3D model. Traditional two-dimensional views and drawings/renderings can be created by the appropriate rotation of the object, and the selection of hidden-line removal via cutting planes. Since wire-frame renderings are relatively simple and fast to calculate, they are often used in cases where a relatively high screen frame rate is needed (for instance, when working with a particularly complex 3D model, or in real-time systems that model exterior phenomena). When greater graphical detail is desired, surface textures can be added automatically after the completion of the initial rendering of the wire frame. This allows a designer to quickly review solids, or rotate objects to different views without the long delays associated with more realistic rendering, or even the processing of faces and simple flat shading. The wire frame format is also well-suited and widely used in programming tool paths for direct numerical control (DNC) machine tools. Hand-drawn wire-frame-like illustrations date back as far as the Italian Renaissance. Wire-frame models were also used extensively in video games to represent 3D objects during the 1980s and early 1990s, when "properly" filled 3D objects would have been too complex to calculate and draw with the computers of the time. Wire-frame models are also used as the input for computer-aided manufacturing (CAM). There are three main types of 3D computer-aided design (CAD) models; wire frame is the most abstract and least realistic. The other types are surface and solid. The wire-frame method of modelling consists of only lines and curves that connect the points or vertices and thereby define the edges of an object.

Simple example of wireframe model An object is specified by two tables: (1) Vertex Table, and, (2) Edge Table. The vertex table consists of three-dimensional coordinate values for each vertex with reference to the origin.

Edge table specifies the start and end vertices for each edge.

A naive interpretation could create a wire-frame representation by simply drawing straight lines between the screen coordinates of the appropriate vertices using the edge list. Unlike representations designed for more detailed rendering, face information is not specified (it must be calculated if required for solid rendering). Appropriate calculations have to be performed to transform the 3D coordinates of the vertices into 2D screen coordinates.

Technical communication explosions In the field of technical communications, technical writers working in mechanical engineering are often assigned to modify, or "explode", engineering models and provide part callouts. CAD wireframe explosions are used to simplify assembly and/or maintenance instructions. Having this capability allows technical writers to independently custom-orient CAD models to improve complex procedural step comprehension. Special CAD software is normally used for this very specialized work and is often available through major CAD software developers. In recent years, however, many new programs for this work are available through smaller developers who specialize in CAD rendering tools.

See also Animation 3D computer graphics Computer animation Computer-generated imagery (CGI) Mockup Polygon mesh Vector graphics Virtual cinematography

References

Further reading Principles of Engineering Graphics by Maxwell Macmillan International Editions ASME Engineer's Data Book by Clifford Matthews Engineering Drawing by N.D. Bhatt Texturing and Modeling by Davis S. Ebert 3D Computer Graphics by Alan Watt

Illustrations

Wire-frame model: Image of a wire-frame object, using hidden-line removal — Image of a wire-frame object, using hidden-line removal

Worked examples

Example 1 — a first encounter with Wire-frame model

Start with the simplest possible case. Write down what Wire-frame model claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Wire-frame model before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Wire-frame model ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Wire-frame model

In research: Wire-frame model appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Wire-frame model in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Wire-frame model is common in secondary-school and first-year university syllabi. It links to neighbouring topics 3D imaging, Computer graphics data structures, Virtual reality, so understanding it makes those chapters shorter.
In everyday life: Look for Wire-frame model outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Wire-frame model in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Wire-frame model means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Wire-frame model out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Wire-frame model in simple terms?

Why does Wire-frame model matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Wire-frame model?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Wire-frame model.