Draft is necessary on surfaces parallel to the direction of die draw because it facilitates ejection of the casting from the die.
It is not common practice to compute the draft for each feature on a component, and it is normally generalised with exceptions noted. Twice as much draft is generally recommended for inside walls or surfaces as for outside walls or surfaces. The reason for this is that as the alloy solidifies and shrinks onto the die features that form the inside surfaces (usually located in the ejector half in conventional cold chamber diecasting), and away from the features that form the outside surfaces (usually located in the cover half in conventional cold chamber diecasting).
The following calculator identifies normal draft requirements for features in a diecasting. Input the depth of the feature from the parting line to see the draft angle required. Critical draft requirements tighter than standard may be achieved as a result of discussion with Dynacast.