Working with Overlay (“Inherited”) VPEs
An overlay VPE (also referred to as an inherited VPE) is created from one or more VPEs and maintains a link to the original(s) so that updates to the parent(s) get passed on to the child.
You can make customizations to the overlay VPE, and these customizations get re-applied after the overlay is updated from a parent VPE. Individual data points in all VPE tables can be overridden, along with individual files in the cost model.
An overlay VPE can inherit values from up to four different parent VPEs, one each for the following:
• Cost Model information
• Material Catalog
• Machines
• Tool Shops
Note: Plant Variables in an overlay VPE are inherited from the Machine VPE. In previous releases, these values were inherited from Cost Model VPE.
When you save an overlay VPE, only the customizations are stored. When you open an overlay VPE, aPriori first loads the data from the parent VPE(s), and then applies all the local customizations.
You can create an overlay VPE from a starting point VPE, a custom VPE, or from another overlay VPE.
Note: Implementing overlay VPEs in a logical fashion requires some advance planning and set-up. For example, if you are just beginning to set up your overlay VPEs, it does not make much sense to assign different starting point VPES to the different areas of your overlay VPE (such as aPriori USA to the Cost Model VPE field, aPriori Mexico to the Material Catalog field, and aPriori China to the Machines field, etc.) Rather, you might create a master overlay VPE for your company from one of the starting points, and customize it with company-specific overrides, and then create regional overlay VPEs from that master with their own customizations for machines and materials, and so on down to finer levels of resolution.
Why use overlay VPEs?
aPriori starting point VPEs provide a starting point for you to set up your production VPEs. You are likely to create one or more custom VPEs to adjust or add some data and logic that reflect your manufacturing practices and buying power. You need to maintain your configurations and customizations, but you also want to continue to update data and logic from aPriori’s semi-annual starting point updates.
Overlay VPEs can be useful in this environment because they inherit from their parents, and then re-apply customizations. This means that VPEs that are derived from an aPriori starting point VPE automatically inherit semi-annual starting point updates, without overwriting your customizations. When you use overlay VPEs, you minimize the number of places you need to update data and logic.
Here are some examples of how you might use overlay VPEs:
• Use an overlay VPE to create a customized cost model based on aPriori starting point data, allowing you to keep it updated with semi-annual starting point VPE updates.
• Create a master custom cost model, but then create regional overlay VPEs from it which inherit the majority of the model but which include small regional customizations (for example, the overlay VPEs all share the same underlying cost model for common processes, but each have their own routing structures).
• Same as above, except that the only difference between the child VPEs and the parent are the machine data, material rates, and logistics logic.
• Create a European overlay VPE in Euros that is based on the USA starting point VPE in US dollars.
• Create a European overlay VPE in Euros that is based on a custom European VPE in Euros.
The following illustrations provide additional visual examples of overlay VPE usage.
Note: Updates to a parent VPE are guaranteed to be propagated to child VPEs only after a restart of aPriori.
It is important to realize that the cost model defines metadata such as columns and column types for machine, material, and tool shop tables. Therefore, if overlay VPE “Company_XYZ_Germany” inherits its cost model from starting point VPE “aPriori Germany”, the only allowable columns for “Company_XYZ_Germany” machines and materials are those defined in the cost model versions for the various process groups in “aPriori Germany”.
If you wanted “Company_XYZ_Germany” to have different columns for machines, materials or tool shops, you would want to create another overlay which inherits from “apriori Germany” and modify the metadata there. You could then have “Company_XYZ_Germany” use that VPE for its cost model base.
Note: Currently, when you override a material or a machine, there is no direct way to determine if a value is inherited or overridden.
To create an overlay VPE
1 If the VPE Toolset is not already open, click Tools > VPE Toolset.
2 Select File > Copy VPE > Maintain inheritance with Source VPE (copy and link)...
This displays the Select Base VPEs dialog.
This displays the Select Base VPEs dialog.
3 Select the VPEs that you want to use as parents for this overlay VPE. Note that if you populate the Cost Model VPE: field, any of the other three VPE fields that are empty will be auto populated by this selection.
In the screenshot below, a number of custom VPEs (probably overlays themselves) have already been created for the company, and these custom VPEs are used as parent for this new overlay VPE.
4 Enter a descriptive name for the new overlay VPE in the New VPE Name: field.
5 Click OK.
6 When done, click the Publish icon (
) to save your changes.
) to save your changes.To determine if a VPE is an overlay
Unless you use a special naming convention, it may not be immediately obvious whether or not a VPE is an overlay. Use this procedure to check, and to identify what VPEs it inherits from.
1 If the VPE is not already open, click File > Open VPE from the aPriori VPE Toolset and then select the VPE from the Select VPE window. Click Open.
2 In the resulting aPriori VPE Manager window, click the top-level entry in the left pane, and then examine the entries in the right pane.
If the VPE is an overlay, you will see an inheritance path for the following lines:
• VPE Inheritance
• VPE Material Inheritance
• VPE Machine Inheritance
• VPE Tool Shop Inheritance
Notes:
1. Regional Data Libraries (RDLs) will display “**Unavailable** in the VPE Inheritance fields.
2. Standalone VPEs will display “N/A” in the VPE Inheritance fields.
1. Regional Data Libraries (RDLs) will display “**Unavailable** in the VPE Inheritance fields.
2. Standalone VPEs will display “N/A” in the VPE Inheritance fields.
To use the Update to Latest buttons
The inheritance lines in the display for an overlay VPE will be appended with Update to Latest buttons in the following circumstances:
• If you or another admin have loaded a newer Regional Data Library or have installed a baseline update for your VPEs.
• If you export this overlay VPE and import it into a newer environment.
Update to Latest for Material, Machine, and Toolshop inheritance tells aPriori to use the latest VPE Data available in the database for the given VPE.
Update to Latest for “VPE Inheritance” applies to the CSL/Base VPE and tells aPriori to use the Cost Model Versions (CMVs) that are shipping with the latest RDL. It does NOT change the actual CMV being used. For example, if in 16,2, you were using CMV 5 and in 17.1 aPriori provides CMV 10, Update to Latest will still result in CMV 5 being used, but now from the 17.1 version.
Update to Latest intentionally does not move you to the latest CMV on the latest RDL because aPriori wants this to be an explicit action on your part, since it is not known what additional migration upgrade work might be required. If your site has performed customizations, simply bumping the CMV could result in a VPE that doesn’t work correctly. This mechanism does allow you to implement bug fixes for older CMVs.
To push plant variables to descendants
You can propagate updates to top level VPE plant variables to all overlay VPEs that inherit machine data from a specific VPE. This is useful for VPE managers who utilize Overlay VPEs within their deployment. For example, if your tool crib labor rate has increased, and your deployment has many VPEs which inherit their machine data from a single “template” VPE, that update can be made in the “template” VPE and this feature can be used to push the updated value down to all of the VPEs that inherit machine data from the “template” VPE..
1 From the VPE Toolset toolbar, click Tools > Push Plant Variables to Dependents
2 From the pull-down menu, select the parent VPE from which you wish to push plant variables.
3 Click OK.
To rename or rebase overlay VPEs
Renaming or rebasing (i.e., changing which VPEs an overlay inherits from) overlay VPEs can be done with out-of-the-box aPriori Professional, but the procedure is manual, complex, and subject to errors due to typos.
If you need to rename or rebase your overlay VPEs, please contact aPriori Customer Support and request the optional “Overlay VPE Rename Script”.