Most system tools have a single output, but custom model and script tools—tools that you create—can have multiple outputs, and tool layers created from such tools can be quite useful since all the output of the tool is contained in the tool layer, as opposed to individual layers.
Two rules govern what data in the model will be added as sublayers to the tool layer when executing the tool layer.
- All data elements with Add to display checked.
- All output data element parameters.
Changes made in the model are not reflected in the tool layer until you execute the tool from the tool layer.
Tool layers contain a reference to the tool, not a copy
Tool layers do not contain a copy of the model. They merely contain a reference to the model. The user of the tool layer must have access to the toolbox containing the model. If you give another user a map document containing a model tool layer, you must also give them the toolbox containing the model.
Tool layers do not detect changes to parameters
Tool layers contain the definition of the parameters of the underlying tool. If you change the parameters in any way, you must delete and re-create the tool layer so that the new tool layer contains the new parameter definitions.
It is not necessary to re-create the tool layer if you change the model or script logic; it is only necessary when you change anything related to input and output parameters.