hierarchical transforms and pivot points

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Hi, I have a question about pivot points and transformations. If I want to rotate about a pivot point, I've read that you can translate to the point, do the rotation there and translate back. So a transformation matrix for this might look like: T = Rp * R * inverse(Rp) Where R = Rotation matrix, Rp = translation matrix for translation to the pivot point, and assume post point multiplication. (ie p` = T * p ) My question is would you specify the coordinates of the pivot in world space or local space? If its local space, would it be before or after taking into account the acutal rotation by R? I am pretty confused.

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The pivot point should be in the local space and should not have the rotation applied to it.

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Quote:
 Original post by JohnBoltonThe pivot point should be in the local space and should not have the rotation applied to it.

Thanks John, I worked out a few simple examples and came to the same conclusion. It seems that pivot points for scales should also be specified in local space too.

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