# tdpara

Defines the reference parallelogram for use with selected TDPACK routines.

*Available in version 4.3.1 and later.*

## Prototype

procedure tdpara ( uvw00 [3] : float, uvw10 [3] : float, uvw01 [3] : float )

## Arguments

*uvw00*

A float array of 3 elements defining the position of the "origin" of the parallelogram: the point with parallelogram coordinates (0,0).

*uvw10*

A float array of 3 elements defining the U, V, and W components of the vector from the origin of the parallelogram to the point with parallelogram coordinates (1,0).

*uvw01*

A float array of 3 elements defining the U, V, and W components of the vector from the origin of the parallelogram to the point with parallelogram coordinates (0,1).

## Description

This initialization routine is part of the low-level TDPACK package, which is a group of Fortran and C callable routines for projecting objects from a 3-dimensional coordinate system having U, V, and W axes to a 2-dimensional projection plane having X and Y axes and/or for drawing the projections of those objects. This can be referred to somewhat loosely as "drawing objects in three dimensions".

This routine may be thought of as an initialization routine or as just a routine to access certain internal values; it simply transfers the values of its arguments into TDPACK labelled common blocks for later use by other TDPACK routines.

Please see the documentation on TDPARA for a full description of this procedure.

## See Also

Initialization routines:
**tdinit**,
**tdclrs**

Parameter access routines:
**tdgetp**,
**tdgtrs**,
**tdsetp**,
**tdstrs**

Point transforming routines:
**tdprpt**,
**tdprpa**,
**tdprpi**

Line drawing routines:
**tdline**,
**tdlndp**,
**tdlnpa**,
**tdlpdp**,
**tdcurv**,
**tdcudp**

Grid drawing routines:
**tdgrds**,
**tdgrid**

Label drawing routines:
**tdlbls**,
**tdlbla**,
**tdlblp**,
**tdplch**

Surface drawing routines:
**tddtri**,
**tdstri**,
**tditri**,
**tdmtri**,
**tdttri**,
**tdctri**,
**tdotri**,
**tdsort**

Simplified interface routines:
**tdez2d**,
**tdez3d**

## Examples

There are no examples for this function currently. Please see the documentation on TDPARA for more information about this function.