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Commands

### triangles command

**Syntax:**

triangles surf-ID M N

- surf-ID = user-assigned name for triangulated surface
- M = number of vertices that follow
- N = number of triangles and edge connections that follow

**Examples:**

triangles cell 150 100
triangles ER 27000 16000

**Description:**

Define a surface with M vertices and N triangles from successive lines
of the input script. If surf-ID already exists, the new triangles are
added to it. If it doesn't exist, a new surface is created with
default permeability settings for all species.

The ID of a surface can contain alphanumeric characters and
underscores and dashes.

Following the triangles command, the next line in the input script is
skipped (leave it blank). 3 sections of information follow, separated
by blank lines.

The first section has M vertex lines, each with an index (1-M) and 3
coordinates (x,y,z in microns).

The second section has N lines, each with an index (1-N) and 3 integer
vertex indices (1-M) which define the corner points of each triangle.
The 3 indices should be ordered so that applying the right-hand rule
yields a normal vector pointing in the "outward" direction from the
triangle face.

The third section has an index (1-N) followed by 6 integers: i ei j ej
k ek. I,J,K are the 3 triangles this triangle is connected to across
its 3 edges where its 1st edge is between vertices 1-2, its 2nd edge
is between 2-3, and its 3rd edge is between 3-1. I,J,K are integer
values between 1-N. Ei,Ej,Ek is the edge (1-3) on the other triangle
that this edge is connected to. If a triangle has no connection
across a particular edge, than the 2 associated values (e.g. I,Ei)
should be 0.

Note that a long list of triangles can be put in a separate file and
read in via the include command.

**Restrictions:**

The bin command must be used before defining a triangulated
surface.

**Related commands:**

region

**Default:** none