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Hybrid model

As explained in Geometry for Programmers

A hybrid model is a geometric representation that combines smooth surface elements and triangle mesh elements in one model or across interchangeable representations.

A hybrid model combines smooth surface elements with triangle mesh elements in one representation, or switches between them as an operation requires. This balances precise geometry for manufacturing with fast processing and rendering for interactive applications. section 11.0 section 11.6

Figure 11.1 A torus described as a smooth surface (left) and as a triangle mesh of ~10,000 triangles (right)
11-01

Compare a torus represented as a smooth surface with the same shape approximated by roughly 10,000 triangles. section 11.0

Choose the representation according to the practical task:

  • Use triangle meshes when computational cost and rendering speed matter, such as in games, augmented reality, virtual reality, and computer-generated imagery. section 11.0 section 11.6
  • Retain smooth surfaces when precise geometry matters, especially in computer-aided design and manufacturing workflows. section 11.0 section 11.6

3D printing

Traditional 3D printing relied heavily on triangle meshes, including STL files. Modern manufacturing-oriented workflows often preserve both triangles and smooth surfaces because printers and production processes now span curve-ready equipment and precise manufacturing data. section 11.0 section 11.6

How Geometry for Programmers covers it

How deep it goes
Motivates hybrid boundary representation through applications and trade-offs, but defers its mechanics to separate treatments of surfaces and triangles.
Examples
Uses a torus comparison, game models, STL-based printing, and manufacturing workflows as concrete examples.
What it assumes
Introduces the combination only after identifying smooth surfaces and triangle meshes as separate representations.
What you can do after
Evaluate and select smooth or triangular representations according to rendering, computation, or manufacturing requirements.
How it connects
Connects smooth surfaces, triangle meshes, boundary representation, computer-aided design, rendering, and 3D printing.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Geometry for Programmers. The section links point to the parts of the book it draws on.