Fundamentals > Fundamentals > Working with the Model > Layers > Layer Basics > Using a Template Layer Model
Using a Template Layer Model
To use predefined ruled layers, you must define a template model with the required ruled layers specified. This model is designated as the template layer model. To access the template layer model set the default_layer_model config option to <layer_model_name>. Where <layer_model_name> specifies the model name that would be used to define predefined ruled layers for all models (*.prt, *.asm, and *.drw) in session. You must specify the name of the default layer models without an extension. You can create template layer models for a part (*.prt), assembly (*.asm), and drawing (*.drw). For example, if the default_layer_model config option is set to DEF_LAYER_MODEL_NAME, then for a part, Creo Parametric will search for def_layer_model_name.prt, and for an assembly, Creo Parametric will search for def_layer_model_name.asm in the working directory, workspace, and template directory.
If you create a new entity in a part, assembly, or drawing that matches the criteria of any of the predefined rules in a template layer model, a new layer is added to the current model automatically, and the new entity is added to that layer. However, if the template model is not available in the current session and if it is undesignated, then the ruled layers are no longer driven by the template layer model.
When the template layer model is not available, then the existing ruled layers become non-ruled layers and do not collect any items or objects. Additionally, a layer driven from the template layer model (or default layer config) will have the option of making the layer independent of the default layer model. Models that already have layers before a default layer model is used will always have layers that are independent of the default layer model if rules are already defined for the previous layers.