To connect attributes using connection lines
If you mouse over a compound attribute, the Node Editor automatically expands to expose its children to which you can make a connection.
As you mouse over the available inputs, all inputs that can receive the connection are highlighted. This indicates that it is possible to make a connection with this input.
All inputs that cannot receive a connection are greyed out. This indicates that a connection is not possible.
In addition, it also snaps to the ports to which you can make a connection. This allows you to easily identify the attributes that you can connect to.
To connect attributes without expanding the nodes
For more information regarding the different views of the nodes, see Node view modes.
For more information regarding the connection lines in the Node Editor, and what each color represents, see Connection colors in the Node Editor.
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