triangles

5reg

triangles

Replaced by &xml-tri;

Content Model
    triangles ::= (&xml-triangle;*)
Attributes
Name | Type
`ntriangles` | `NUMBER` (required)

&eltdepver;7.0

## Description

This element was used in the past to store all triangles in a 2-manifold triangulation. Since ®ina; 7.0, these triangles are now stored directly within the &xml-tri; element (which replaces the old &xml-packet; element for triangulation packets), and each triangle is encoded in a &xml-simplex; element (as opposed to the &xml-triangle; elements described here).

A &xml-triangles; element stores the entire set of triangles forming a 2-manifold triangulation.

The total number of triangles must be specified by the `ntriangles` attribute. The individual triangles are numbered 0, 1, 2, etc., and their edge gluings are described by the corresponding child &xml-triangle; elements. There must be precisely `ntriangles` child &xml-triangle; elements in total.

### Parents

The following elements contain `triangles`:

- &xml-packet-dim2triangulation;

.

### Children

The following elements occur in `triangles`:

- &xml-triangle;

.

## Attributes

`ntriangles`

- The total number of triangles in this set. Note that there must be precisely this many child &xml-triangle; elements.

## Example

The following &xml; snippet represents a triangulation of the Klein bottle with two triangles.

    <triangles ntriangles="2">
      <triangle> 1 1 1 5 1 0 </triangle>
      <triangle> 0 1 0 5 0 0 </triangle>
    </triangles>