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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:
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3 direction vectors (X, Y, Z axes — orientation)
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1 position vector (T — translation)
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1 extra row that supports homogeneous coordinates
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Identity Matrix
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Does nothing when applied to a vector.
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Basis for understanding other transformations.
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Represents standard world coordinates.
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Uniform Scaled Matrix
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Modify all diagonal values equally.
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Scales objects equally in all directions.
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E.g.,
0.5
on all diagonal entries = mesh is scaled down by half.
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Axis Scaled Matrix
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Change individual diagonal values independently.
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Scales the object along specific axes.
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E.g., a 3 in the X-axis = stretches object 3x in X only.
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Mirror (Reflection) Matrix
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Multiply a diagonal entry by
-1
to mirror on that axis. -
E.g.,
-1
in X = flips mesh on the X-axis.
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Matrix with Normalized Basis
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Basis vectors (matrix columns) are unit length and orthogonal.
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Often used for pure rotation without scaling.
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Each axis remains perpendicular and consistent in size.
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Matrix with Non-Orthogonal Basis
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Columns are not perpendicular.
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Causes skewing—object axes are no longer at right angles.
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Matrix with Non-Normalized Basis
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Basis vectors may differ in length.
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Can scale along arbitrary axes (not just X, Y, Z).
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Rotation Matrices
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Represented by changing off-diagonal values (not just diagonal).
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Rotate vectors in space while maintaining their magnitude.
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Matrix Interpretation Tip
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Think of each matrix column as defining a new space axis.
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Multiplying a vector by a matrix expresses it in that new space.
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Let me know if you’d like a diagram or Unity version of any of these!