Revisions to How to compute the origin/pivot point of objects in a hierarchy

corrected spelling

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edited Dec 4, 2021 at 12:43

Suic

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float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Matrix.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Matrix.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Matrxbone3Matrix.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Matrix.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Matrix.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Matrx.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Matrix.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Matrix.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Matrix.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

Made a mistake in my last example

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edited Dec 4, 2021 at 12:17

Suic

119
6

float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Rotationbone1Matrix.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Rotationbone2Matrix.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Rotationbone3Matrx.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Rotation.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Rotation.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Rotation.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Matrix.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Matrix.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Matrx.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

added my current understanding of how i could possibly do it with matrices

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edited Dec 4, 2021 at 11:57

Suic

119
6

Using matrices this is what i thought could potentially work, but im not 100% sure: if i were to rotate Bone1 which has 3 children(including indirect) (Bone 2-4)

float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Rotation.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Rotation.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Rotation.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

And the origin of each bone would just be the translation part of their matrix(just a guess)

the rotation of each bone would either be the accumulated rotation or the initial rotation(i'd assume it's the latter)

Using matrices this is what i thought could potentially work, but im not 100% sure: if i were to rotate Bone1 which has 3 children(including indirect) (Bone 2-4)

float rotation = PI / 4; // 45 degrees

Matrix bone1Matrix = Matrix.identity().translate(Bone1.localPosition).rotateX(rotation)

Matrix bone2Matrix = bone1Rotation.multiply(Matrix.identity().translate(Bone2.localPosition).rotateX(rotation)

Matrix bone3Matrix = bone2Rotation.multiply(Matrix.identity().translate(Bone3.localPosition).rotateX(rotation)

Matrix bone4Matrix = bone3Rotation.multiply(Matrix.identity().translate(Bone4.localPosition).rotateX(rotation)

And the origin of each bone would just be the translation part of their matrix(just a guess)

the rotation of each bone would either be the accumulated rotation or the initial rotation(i'd assume it's the latter)

added 47 characters in body

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edited Dec 4, 2021 at 7:54

Suic

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added 521 characters in body

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edited Dec 4, 2021 at 7:49

Suic

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added 648 characters in body

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edited Dec 3, 2021 at 22:35

Suic

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asked Dec 3, 2021 at 22:23

Suic

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