# udfGetNbcAuxRefCrd()

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

## Syntax

auxCrd = udfGetNbcAuxRefCrd( 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 reference 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 initial condition nodal coordinates at the auxiliary nodes. If mesh
displacement is active, the returned coordinates include the initial conditions for the mesh
displacement; that is, the initial deformed configuration. For
example,

```
Real* auxCrd ;
Real x, y, z ;
Integer node ;
...
udfCheckNbcNumAuxs( udfHd, 1 ) ;
auxCrd = udfGetNbcAuxRefCrd( udfHd ) ;
for ( node = 0 ; node < nItems ; node++ ) {
x = auxCrd[0*nItems+node] ;
y = auxCrd[1*nItems+node] ;
z = auxCrd[2*nItems+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.