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ShearingMatrix

ShearingMatrix[Theta, v, n]
gives the matrix corresponding to shearing by Theta radians along the direction of the vector v, and normal to the vector n.
  • ShearingMatrix gives matrices corresponding to shearing with the origin kept fixed.
  • ShearingMatrix gives matrices with determinant 1, corresponding to area- or volume-preserving transformations.
  • In 3D, ShearingMatrix does the analog of shearing a deck of cards by angle Theta in the direction v, with the cards being oriented so as to have normal vector n.
A shearing by Theta radians along the x axis:
Apply a 30° shear along the x axis to a square:
A shearing by Theta radians along the x axis:
In[1]:=
Click for copyable input
Out[1]//MatrixForm=
 
Apply a 30° shear along the x axis to a square:
In[1]:=
Click for copyable input
Out[1]=
Shearing along the x axis:
Shearing along the y axis:
Shearing in the x, y plane along the x axis:
Shearing the x, z plane along the x axis:
A shearing by angle theta in the {1,1} direction in the line {1,-1}.p==0:
Transformation applied to a 2D shape:
Transformation applied to a 3D shape:
Applying the transformation to a surface:
Generate all simple (directions parallel to axes) shearing matrices for dimension n:
All shearings in 2D:
All shearings in 3D:
All shearings in 4D:
The determinant of a shearing matrix is 1; hence it preserves areas and volumes:
The inverse of ShearingMatrix[Theta, v, n] is given by ShearingMatrix[-Theta, v, n]:
The inverse of ShearingMatrix[Theta, v, n] is also given by ShearingMatrix[Theta, -v, n]:
The n^(th) power of a shearing matrix is again a shearing matrix with the same v and n:
The order in which shearings are applied is significant:
Here the two different orders do not yield the same matrix:
The transformation is not defined for angles a such that cos a=0:
For non-orthogonal vectors, the direction is determined by the projection of the direction vector:
The transformation applied to a sphere:
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