# SoGetMatrixAction.3iv man page

SoGetMatrixAction ā 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**