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Vectors describe positions or directions within a coordinate space.
Matrices describe how to transform vectors from one space to another.

 

[ Xaxis.x  Yaxis.x  Zaxis.x  Tx ]
[ Xaxis.y  Yaxis.y  Zaxis.y  Ty ]
[ Xaxis.z  Yaxis.z  Zaxis.z  Tz ]
[   0        0        0      1 ]

A 4×4 transformation matrix is made up of:

  • 3 direction vectors (X, Y, Z axes — orientation)

  • 1 position vector (T — translation)

  • 1 extra row that supports homogeneous coordinates

 

  • Identity Matrix

    • Does nothing when applied to a vector.

    • Basis for understanding other transformations.

    • Represents standard world coordinates.

  • Uniform Scaled Matrix

    • Modify all diagonal values equally.

    • Scales objects equally in all directions.

    • E.g., 0.5 on all diagonal entries = mesh is scaled down by half.

  • Axis Scaled Matrix

    • Change individual diagonal values independently.

    • Scales the object along specific axes.

    • E.g., a 3 in the X-axis = stretches object 3x in X only.

  • Mirror (Reflection) Matrix

    • Multiply a diagonal entry by -1 to mirror on that axis.

    • E.g., -1 in X = flips mesh on the X-axis.

  • Matrix with Normalized Basis

    • Basis vectors (matrix columns) are unit length and orthogonal.

    • Often used for pure rotation without scaling.

    • Each axis remains perpendicular and consistent in size.

  • Matrix with Non-Orthogonal Basis

    • Columns are not perpendicular.

    • Causes skewing—object axes are no longer at right angles.

  • Matrix with Non-Normalized Basis

    • Basis vectors may differ in length.

    • Can scale along arbitrary axes (not just X, Y, Z).

  • Rotation Matrices

    • Represented by changing off-diagonal values (not just diagonal).

    • Rotate vectors in space while maintaining their magnitude.

  • Matrix Interpretation Tip

    • Think of each matrix column as defining a new space axis.

    • Multiplying a vector by a matrix expresses it in that new space.

Let me know if you’d like a diagram or Unity version of any of these!