[Closed] ObjectOffset Rotation/Transform

Its rare case but some people are lazy and the move cam pivot to get easy rotation in orbit style, When you do CANERA transfer you need OPTICAL CENTER LOCATION not PIVOT LOCATION. So transform node means PIVOT POINT and objectransform means “ACTUAL” OBJECT POSITION.

Read this:

[left]A node’s transform property contains the Node Transform Matrix, and reflects the position, rotation, and scale of the node’s pivot point. Accessing the pivot property will return the same value as the pos property. Setting the pivot property will move the pivot point location to the specified coordinates, however the node’s geometry will not be moved.
[/left]
[left]A node’s objectoffsetpos, objectoffsetrot, and objectoffsetscale properties contain the component parts of the Object-Offset Transform Matrix. A node’s objecttransform property contains the Object Transform Matrix. Since this matrix is a combination of the Node Transform and Object-Offset Transform Matrices, this property is read only. Note that these properties are always returned in the World coordinate system context.
[/left]

The object-offset transform is the offset of the object itself to its pivot i.e its node transform. I.e if you moved an objects mesh, leaving its pivot(node transform) behind you would be moving its object-offset relative to world space.

Generally with cameras, people dont tend to change the cameras actual pivot, they just parent it to another object an rotate that. If however you did and yes did infact need to get its original pivot it would be a little tricky and you would want to apply back its node transform to the the object, and the transform the object-offset by its inverse.

Alot of people find the object-offset and node transforms very strange and can over complicated it, max has one of the strongest matrix and node transform support. Essentially all your doing its applying an offset to a transform, the transform being the pivot and the object being the object or mesh itself.

The only reason an object would need to apply the object-offset back onto is if the node transform itself was positionally at zero or the camera’s pivot was wrong and an offset needed to be applied to it. Simliar to mocap data that needs to point up in z or y.

If your camera’s pivot is correct, and its orbiting or pan etc around another object, etc or even if its just moving it space all you really need to do is store its world transform over time.

Its funny that your adding an object-offset on top, isnt this just changing the cameras object and not its pivot? Does nuke use the actual object center? not node?

This should properly align the box:

a = box()
a.rotation = inverse $.transform.rotation
a.pos = $.pos

Note that the rotation is performed before translation, the other way around will not work due to the way matrices work.
A simpler method however would be:

a = box transform:$.transform

The objectoffset pos/rot/scale properties contain the offset from the pivot to the node’s actual geometry. So if you would select the target camera in your example, and move the camera’s pivot using “Affect Pivot Only”, the above scripts would not align the box to the camera node, but the pivot (just like it did before, but then the pivot wasn’t changed, so the objectoffsets where still aligned to the world). To force the script to align the box to the camera instead of its pivot, you need to multiply the offset transformation by the node’s transformation:

(
  -- calculate the offset transform matrix
  local TmScale  = scaleMatrix $.objectOffsetScale
  local TmRot    = $.objectOffsetRot as matrix3
  local TmPos    = transMatrix $.objectOffsetPos
  local TmOffset = TmScale * TmRot * TmPos

  a = box transform:(TmOffset * $.transform)
)

Luckily, nodes have a readonly property called objectTransform which already contains these multiplied matrices, so this would reduce the script to:

a = box transform:$.objectTransform

Hope this helps,
Martijn