.. meta::
    :description: Code snippets affine transform UnstructuredGrid

How to apply an affine transform to an UnstructuredGrid
=======================================================

In this example we will apply an affine transform to different UnstructuredGrid.
UnstructuredGrid is an abstract class who has 2 concrete subclasses:
HalfEdgeMesh and FaceVertexMesh.


Let's start by creating an instance of each of the UnstructuredGrid subclasses::

    from ORSModel import Channel
    from ORSModel import FaceVertexMesh, HalfEdgeMesh
    channel = Channel()
    channel.setTitle('demo channel')
    #set it sizes, since we use the default voxel size, the channel is for now 100 meter cube
    channel.setXYZTSize(100,100,100,1)
    channel.setXSpacing(0.01)
    channel.setYSpacing(0.01)
    channel.setZSpacing(0.01)
    #now the channel is 1 meter cube
    #initilize it for float32 data
    channel.initializeDataForFLOAT()
    channelBox = channel.getBox()
    channelBox.grow(orsVect(-channelBox.getDirection0Size()*0.5, -channelBox.getDirection1Size()*0.5, -channelBox.getDirection2Size()*0.5))
    channel.paintBox(channelBox,  1, 0)
    channelBox.grow(orsVect(-channelBox.getDirection0Size()*0.5, -channelBox.getDirection1Size()*0.5, -channelBox.getDirection2Size()*0.5))
    channel.paintBox(channelBox,  2, 0)
    channel.setDataDirty()
    #publish it so that it is visible in the Object properties list
    channel.publish()
    faceMesh = FaceVertexMesh()
    channel.getAsMarchingCubeMesh(1 - 0.001, True, False, 0, 1, 1, 1, False, True, None, faceMesh)
    faceMesh.setTitle('Face mesh')
    halfEdgeMesh = HalfEdgeMesh()
    channel.getAsMarchingCubeMesh(2 - 0.0001, True, False, 0, 1, 1, 1, False, True, None, halfEdgeMesh)
    halfEdgeMesh.setTitle('Half edge mesh')
    faceMesh.publish()
    halfEdgeMesh.publish()


Let's define an affine transform::

    translation = Matrix4x4()
    translation.setTranslation(channel.getBox().getDirectionSizeVector()*0.25)
    rotationAxis = orsVect(0, 1, 0)
    rotation = Matrix4x4()
    rotation.setAsRotation(rotationAxis, 3.1416/8)
    scale = Matrix4x4()
    scale.setScale(orsVect(0.5,1,2))
    #now let's concatenate these transformation, in an arbritrary order
    fullTransform = scale*rotation*translation

Let's apply the affine transformation::

    faceMeshT = faceMesh.copy()
    faceMeshT.setTitle(faceMesh.getTitle() + ' transformed')
    faceMeshT.publish()
    faceMesh.getTransformed(fullTransform, faceMeshT)
    halfEdgeMeshT = halfEdgeMesh.copy()
    halfEdgeMeshT.setTitle(halfEdgeMesh.getTitle() + ' transformed')
    halfEdgeMeshT.publish()
    halfEdgeMesh.getTransformed(fullTransform, halfEdgeMeshT)