When VTS builds a new application based on a layer (either the VTS layer or a customized application layer), it looks for a Template directory. Each new application that is built is given a blank template directory for you to use.
An example of layer inheritance can be seen when you create a new standard application based on the VTS layer. A Template directory resides within the VTS layer directory and includes several template files. When a new standard application is based on the VTS layer, the contents of the VTS layer's Template directory are copied directly into the new application's directory.
In addition to the contents of the VTS layer's Template directory, a new blank template directory is created in the new application's directory. This Template directory can be used to store directories and files that you wish to be copied to subsequent application layers.
Note: Not all files should be included in the template directory. For example, AppMod.SRC and GDI.WIF should never be included as template files. Examples of what should go into the template directory can be found in the topic: VTS Template Directories.
Since there are duplicates of certain files and directories within the application directories and within the VTS layer directory (e.g. the "Config.ini" configuration file, or the "Bitmaps" directory), you may wonder how VTS treats these duplicate resources.
Because applications are built in layers, with every new application being built on at least one layer (the VTS layer), VTS begins to search the uppermost application layer for the files and directories it relies upon to function. If it does not find them in the uppermost layer, it continues to search down through the layers until the appropriate files have been located. As a rule, VTS runs the first instance of a required file that it finds.
Therefore, when you run your application layer, VTS loads whatever files and directories it needs from this layer, and then searches the next layer for any files and directories it did not find in the upper layer. This process continues until VTS reaches the VTS layer; any files and directories not found in the upper layers will be loaded from the VTS layer, giving your application access to them.
Note: A slight variation of this process occurs with the configuration file, Config.INI. In this case, VTS loads the first instance of each configuration variable it finds from each of the configuration files. The configuration file is loaded from every layer, but for any given variable, only the first instance found is used. As a rule, configuration files in upper layers contain only the variables that are to differ from those in the underlying layers.
Points.MDB always copied
There is one exception to the template system: All tag instances in an OEM layer are always copied to a new application when it is created. It is not necessary to add the file Points.MDB to the template directory to achieve this.
Pages and drawn instances of the tags are not inherited unless the page files are included within the template directory.