# Define a Mask for a Downstream Tool

When Cognex Deep Learning Tools are connected together in a tool chain, the mask for a preceding tool is used by the following tools. For example, if a mask is created in Tool 1, and Tool 2 is chained to Tool 1, Tool 2 inherits the mask of Tool 1. If you add an additional mask to Tool 2, then Tool 2 uses both masks.

To edit the mask of Tool 1 for use by Tool 2, select Edit Mask while Tool 1 is the active tool.