It is possible to create Calculated Fields using attributes from other objects.
Cross-object references as part of custom data are slightly different from those used in the Text Mode interface for filters and views. Instead of using the bean reference (:), which is always in camel case, object aliases have been developed for the Custom Data interfaces.
With Text Mode attributes you navigate between relationships using a colon; however, when making these connections in Calculated fields you will use a period.
Remember it is not possible to reference data from child objects (subtasks). For example, you cannot pull task data into a project-level expression because of the sub level relationship. However, from the task perspective, you can always include project-level details.
Object: Project Name
Text Mode Reference: project:name
Custom Data Reference: project.name