CODEWITHSUNDEEP
c#.netwpf3d
bradgonesurfing
bradgonesurfing

Reputation: 32192

What is Point4D used for in WPF 3D?

What is the normal use case for Point4D vs Point3D?

Is it for handling special geometry or just carrying a scalar field value around with the point or something more specialized?

Upvotes: 1

Views: 783

Answers (1)

Govert
Govert

Reputation: 16907

In order to represent a 3D affine transform where there might be a translation in addition to scaling and rotation as a matrix transform, you need to extend to 4D points and a 4x4 augmented matrix. (Consider that a 3x3 matrix could not translate the point (0, 0, 0) to a different location.)

In WPF the Matrix3D structure represents a 4x4 matrix, and Point4D is the augmented vector structure that you can multiply by a Matrix3D matrix. The extended vectors are sometimes called 'homogeneous 3D coordinates'.

Upvotes: 2

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