# DP Card

The DP card is used to define points in space. These points are used to define the extent and orientation of other geometric entities and to locate excitations.

On the Home tab, in the Define group, click the  Point (DP) icon.

To avoid ambiguity each point is assigned a name (a 5 character string if column based format is used.) In other cards (for example the BL card) the points are referred to by their names.

## Parameters:

Point name
Name of the point.
X coordinate
X coordinate of the point in m (is scaled by the SF card).
Y coordinate
Y coordinate of the point in m (is scaled by the SF card).
Z coordinate
Z coordinate of the point in m (is scaled by the SF card).
Nurb control point weight
The weight of the control point when this point is used with the NU card (NURBS surfaces). If the field is empty, it defaults to 1.

## Examples of DP Card Usage

In addition to its coordinates, each point is also assigned the current label (see LA card), so that a group of points can be selected by label, for example when moving points with the TP card. Point names may use the characters a-z, A-Z, 0-9 and the special character _ and no distinction is made between upper and lower case characters. Thus P1a and p1A refers to the same point. In addition, when defining or using node names, simple variable names of the form A#i are allowed. The algorithm is that if a hash sign is found in a node point name, this hash sign and everything that follows is interpreted as a variable string, evaluated and rounded to the nearest integer. Thus if we have #k=15 and use or define a point P#k then this is equivalent to using P15 as point name.
[node!variable name]
For instance, it would now be possible to define the points P1 to P20 inside a loop.
!!for #k = 1 to 20
DP: P#k
!!next

Unlike most other geometry cards, the DP card (as well as the TP card) may also be used in the control section (after the EG card) of the .pre file. This allows defining the points required by the AP card in this part of the file.