# SoGetMatrixAction.3iv man page

SoGetMatrixAction — computes transformation matrix for subgraph

## Inherits from

SoAction > SoGetMatrixAction

## Synopsis

**#include <Inventor/actions/SoGetMatrixAction.h>**

Methods from class SoGetMatrixAction:

**SoGetMatrixAction(const SbViewportRegion &newRegion)****void** **setViewportRegion(const SbViewportRegion &newRegion)****const SbViewportRegion &** **getViewportRegion() const****SbMatrix &** **getMatrix()****SbMatrix &** **getInverse()****SbMatrix &** **getTextureMatrix()****SbMatrix &** **getTextureInverse()**

Methods from class SoAction:**virtual void** **apply(SoNode *node)****virtual void** **apply(SoPath *path)****virtual void** **apply(const SoPathList &pathList, SbBool obeysRules = FALSE)****static SoType** **getClassTypeId()****virtual SoType** **getTypeId()****virtual SbBool** **isOfType(SoType type)****virtual void** **invalidateState()**

## Description

This action computes transformation matrices for a given subgraph. It computes the cumulative transformation matrix and its inverse, along with a cumulative texture transformation matrix and its inverse.

This action is unlike most others in that it does not traverse downwards from groups. When applied to a node, it computes the matrix for just that node. (This makes sense for transformation nodes, but not for others, really.) It is much more useful when applied to a path. When applied to a path, it gathers the transformation info for all nodes in the path and those that affect nodes in the path, but it stops when it hits the last node in the path; it does not traverse downwards from it as other actions (such as rendering) do. This behavior makes the most sense for this action.

## Methods

**SoGetMatrixAction(const SbViewportRegion &newRegion)**

Constructor takes viewport region to use for picking. Even though the matrix computation may not involve a window per se, some nodes need this information to determine their placement. **void** **setViewportRegion(const SbViewportRegion &newRegion)****const SbViewportRegion &** **getViewportRegion() const**

Sets/returns current viewport region to use for action. **SbMatrix &** **getMatrix()****SbMatrix &** **getInverse()**

Returns cumulative transformation matrix and its inverse. Warning: the matrices returned by these routines should not be changed (unless you are implementing your own transformation nodes). **SbMatrix &** **getTextureMatrix()****SbMatrix &** **getTextureInverse()**

Returns cumulative texture transformation matrix and its inverse. Warning: the matrices returned by these routines should not be changed (unless you are implementing your own transformation nodes).

## See Also

**SoGetBoundingBoxAction**