#### INITIAL_MATERIAL_DIRECTION

###### Initial conditions
*INITIAL_MATERIAL_DIRECTION
"Optional title"
nid, $\hat{x}_x$, $\hat{x}_y$, $\hat{x}_z$, $\bar{y}_x$, $\bar{y}_y$, $\bar{y}_z$
##### Parameter definition
VariableDescription
nid Node ID
$\hat{x}_x$, $\hat{x}_y$, $\hat{x}_z$ Direction of local x-axis
$\bar{y}_x$, $\bar{y}_y$, $\bar{y}_z$ Vector needed for the definition of the local y- and z-axis
##### Description

This command is used to define local material directions. Data is input for the element corner nodes. The local directions at the element integration points at time 0 are interpolated from the element corner node values. The local y-axis ($\hat{\mathbf y}$) and z-axis ($\hat{\mathbf z}$) are defined as:

$\displaystyle{ \hat{\mathbf z} = \frac{\hat{\mathbf x} \times \bar{\mathbf y}}{\vert \hat{\mathbf x} \times \bar{\mathbf y} \vert}}$
$\displaystyle{ \hat{\mathbf y} = \hat{\mathbf z} \times \hat{\mathbf x}}$

Alternative commands for definitions of local material directions are INITIAL_MATERIAL_DIRECTION_VECTOR and INITIAL_MATERIAL_DIRECTION_WRAP.