Separate group and model
As #8289 (closed) showed, the sao design of separating Group and Model definition is a safer design. Also it will reduce the memory consumption as the Model will be shared between all the level of the tree.
As #8289 (closed) showed, the sao design of separating Group and Model definition is a safer design. Also it will reduce the memory consumption as the Model will be shared between all the level of the tree.