Friday, December 28, 2012

Costing items multiple different ways per item in Dynamics AX 2009


In AX 2009 inventory costing is controlled by the Dimensions group assigned to an Item when using the weighted avg costing method.

Dimension group setup is found under "Inventory Management > Setup > Dimensions > Dimension groups" and the dimension group is assigned to an item under "Item details > General tab > Dimension group field".

On the dimension group inventory dimensions can be marked as Active to become available for entry and selected for "Financial inventory" to be considered for costing purposes.

Imagine if you setup your inventory dimension group to have Size (inventsize), Color (inventcolor), Site (inventsiteid), and Warehouse (inventlocationid) to be active and financial inventory. This means that when inventory is issued (sold) the cost of the inventory is calculated based on all existing inventory that matches the combination of size, color, site, and warehouse. Another way of saying this is that the inventory is averaged by these dimensions.


Inventory is purchase at a cost of $10 per unit for a specific item, size, color, site, and warehouse. Then the same quantity is also purchases for $20 per unit with the same combination of item, size, color, site, and warehouse. If the inventory is now sold, it will be taken out of inventory at a cost of $15 per unit. Any inventory receipts that match this specific combination of item and dimensions will therefor effect the issue cost.


One problem with this approach is that an item can only be assigned to one inventory dimension group. An example of when this can be an issue is when we want to cost items of one color one way and items of a different color another way. It would be possible to setup up additional items to accomplish this, but if this is a common practice you would not want to have to duplicate items to handle this.


One work around for this problem is to modify the code where the dimension group is found and used to use a different dimension group based on a dimension value. The way we handled this was to add a new field to the dimension group table (inventDimGroup) which references another dimGroupId on the same table. In this way we can assign one dimension group to an item, but then also assign special purpose dimension groups.

Once this is done the class InventOnHand::newFinancialUpdate() method should be updated to first inspect the inventDim passed in and then choose whether to initFinancialInvent with the passed in _movement.dimGroupId or with the new field we added to that table.

Example code

//Find the dimGroupId for RED items
redGroupId = inventDimGroup::find(_movement.dimGroupId()).dimGroupIdRed;

if(_inventDim.InventColorId == inventparameters.redColor && asnGroupId != "")