image and geo anchors only work at the root of a scene

[blairmacintyre]

The transforms associated with the "anchor" are relative to the local coordinates.

If an anchor is below the root, we need to do the following:

• assume the parent you want to attach it to is P. mp = P.matrixWorldInverse
• attach an extra group node G to P. set G.matrix to mp. This should result in G.matrixWorld being the identity
• now attach the node that the anchor transform will be applied to as a child of G. Things will work

[joshmarinacci]

is there ever a reason to have an anchor not as an immediate child of the scene?

[blairmacintyre]

For "scene organization" type things: I have a group of content that I'd like to turn on/off together. Multiple geo nodes, for example. Putting them under a group would be obvious. But now the group is under the "scene origin anchor".

[blairmacintyre]

(@joshmarinacci I will still do this, I'm just marking it as Next to remind myself)