# udfGetNbcAuxCrd()

Return the nodal coordinates for the nodal boundary condition at the auxiliary nodes.

## Syntax

auxCrd = udfGetNbcAuxCrd( udfHd ) ;

## Type

AcuSolve User-Defined Nodal Boundary Condition

## Parameters

- udfHd
- The opaque handle (pointer) which was passed to the user function.

## Return Value

- auxCrd (Real*)
- Pointer to three dimensional real array of nodal coordinates at the auxiliary nodes. The first (fastest) dimension of the array is the number of nodes, nItems, the second dimension is the number of auxiliary nodes, nAuxs, and the third (slowest) dimension is three, for the x, y and z coordinates. If nAuxs is one, then the array may be treated as two dimensional.

## Description

This routine returns the nodal coordinates at the auxiliary nodes. If mesh displacement is
active, the returned coordinates are for the current (deformed) configuration. For
example,

```
Real* auxCrd ;
Real x0, y0, z0, x1, y1, z1, x2, y2, z2;
Integer node, nAuxs=3 ;
...
udfCheckNbcNumAuxs( udfHd, nAuxs ) ;
auxCrd = udfGetNbcAuxCrd( udfHd ) ;
for ( node = 0 ; node < nItems ; node++ ) {
x0 = auxCrd[nItems*(0*nAuxs+0)+node] ;
y0 = auxCrd[nItems*(3*nAuxs+0)+node] ;
z0 = auxCrd[nItems*(6*nAuxs+0)+node] ;
x1 = auxCrd[nItems*(0*nAuxs+1)+node] ;
y1 = auxCrd[nItems*(3*nAuxs+1)+node] ;
z1 = auxCrd[nItems*(6*nAuxs+1)+node] ;
x2 = auxCrd[nItems*(0*nAuxs+2)+node] ;
y2 = auxCrd[nItems*(3*nAuxs+2)+node] ;
z2 = auxCrd[nItems*(6*nAuxs+2)+node] ;
...
}
```

## Errors

- This routine expects a valid udfHd.
- This routine may only be called within a Nodal Boundary Condition user function.
- The corresponding command must have a valid auxiliary_nodes parameter.