The context for this topic is this bug report (3 comments and 1 video that quickly explains my confusion):
How should I put this?
Intuitively, I think of
Capture Attribute as remembering (data from) the previous state of a mesh, before being changed. Or just “Capturing” certain vertices to only
Raycast from those vertices alone, instead of the whole mesh.
Capture Attribute manual kind of says the same thing:
This node is essential because field input nodes like the Radius Node work in the context of the node they are connected to. Meaning that in order to pass data like radius to a geometry that doesn’t have radius, an explicit node link with the output of this node must be used.
According to Hans it seems that
Capture Attribute will work further down the node tree only if at the point you are using it, that object has that specific Anonymous Attribute that you want to manipulate. (i.e. if you Capture a Radius to use on a geometry that doesn’t have a Radius, then nothing will happen, contrary to the manual).
Solution proposed by Hans in the bug report is that I use
Transfer Attribute, but I don’t want to transfer or map/interpolate any data between any objects. I want to use data that exists at some previous point in the tree, and use it later.
This brief interaction left me with many questions:
- If that is the intended way of working for
Capture Attribute(in 3.0), then why does it work like I expected it to work, in 3.1, which is different? (download the example file from the bug report and see with 3.1 it behaves differently)
- Why have Capture Attribute at all, if you can just use
Transfer Attributethen? (difference of use case?)
- What should change? The Node, the Manual, or my understanding of these 2? (I can be hilariously wrong)
PS: I hope Hans won’t hate me for this thread. I’m not trying to point fingers at anyone or anything. I just feel that something, somewhere, isn’t clear as to what it should do and I’m hoping this thread can shed some light, and I don’t want to post this kind of discussion on the bug tracker…