The affectsState() Method

The affectsState() method on SoNode indicates whether a node has a net effect on the state. (For example, SoSeparator changes the state, but it restores the state, so there's no net effect.) The default value for this method is TRUE, but some node classes such as SoSeparator, SoShape, SoArray, and SoMultipleCopy define it to be FALSE. When you define a new node class, you may need to redefine its affectsState() method if it differs from that of the parent class.