TIN Files

TIN files are used for storing triangulated irregular networks. The TIN file format is shown in Figure 1 and a sample file is shown in Figure 2. The TIN file format can be used to import a simple set of xyz coordinates since the triangle information (beginning with the TRI card) does not need to be present. If you have a file of xyz coordinates you only need to add the TIN, BEGT, and VERT nv cards to the top of the file and the ENDT card at the end.

TIN

/* File type identifier */

BEGT

/* Beginning of TIN group */

TNAM name

/* Name of TIN */

TCOL id

/* TIN material id */

VERT nv

/* Beg. of vertices */

x1 y1 z1 lf1

/* Vertex coords. */

x2 y2 z2 lf2

 

.

 

.

 

.

 

xnv ynv znv lfnv

 

TRI nt

/* Beg. of triangles */

v11 v12 v13

/* Triangle vertices */

v21 v22 v23

 

.

 

.

 

.

 

vnt1 vnt2 vnt3

 

ENDT

/* End of TIN group */

Figure 1. TIN File Format.

 

TIN

BEGT

TNAM Aspen

TCOL 255 255 255

VERT 408

0.0 3.1 7.8 0

5.3 8.7 4.0 1

.

.

2.4 4.4 9.0 1

TRI 408

5 1 4

4 1 2

.

.

4 2 3

ENDT

Figure 2. Sample TIN File.

 

The cards used in the TIN file are as follows:

Card Type

TIN

Description

File type identifier. Must be on first line of file. No fields.

Required

YES

 

Card Type

BEGT

Description

Marks the beginning of a group of cards describing a TIN. There should be a corresponding ENDT card at a latter point in the file. No fields.

Required

YES

 

Card Type

TNAM

Description

Provides a name to be associated with the TIN.

Required

NO

Format

TNAM name

Sample

TNAM aspen

Field

Variable

Value

Description

1

name

str

The name of the TIN.

 

Card Type

TCOL

Description

Defines a default color for the triangles of the TIN

Required

NO

Format

TCOL color_red color_green color_blue

Sample

TCOL 255 255 255

Field

Variable

Value

Description

1

color_red

0-255

The red color component of TIN triangles.

2

color_green

0-255

The green color component of TIN triangles.

3

color_blue

0-255

The blue color component of TIN triangles.

 

Card Type

VERT

Description

Lists the vertices in the TIN

Required

YES

Format

VERT nv

x1 y1 z1 lf1

x2 y2 z2 lf2

.

.

xnv ynv znv lfnv

Sample

VERT 4

0.0 3.1 7.8 0

5.3 8.7 4.0 1

2.4 4.4 9.0 1

3.9 1.2 3.6 0

Field

Variable

Value

Description

1

nv

+

The number of vertices in the TIN

2-4

x,y,z

Coords. of vertex

5

lf

0,1

Locked / unlocked flag for vertex (optional). 0=unlocked, 1=locked. Repeat fields 2-5 nv times.

 

Card Type

TRI

Description

Lists the triangles in the TIN

Required

NO ( a set of triangles can be generated from the vertices)

Format

TRI nt

v11 v12 v13

v21 v23 v23

.

.

vnt1 vnt2 vnt3

Sample

TRI 4

5 1 4

4 1 2

4 2 3

5 4 3

Field

Variable

Value

Description

1

nt

+

The number of triangles in the TIN.

2-4

v1,v2,v3

+

Vertices of triangle listed in a counter-clockwise order. Repeat nt times.

 

Card Type

ENDT

Description

Marks the end of a group of cards describing a TIN. There should be a corresponding BEGT card at a previous point in the file. No fields.

Required

YES