When I issue SHOW statement of a large table/view/macro definition, Teradata Studio doens't show the result set in the Result Set Viewer. Instead, the script is exported as RequestText*.txt. Is this by design?
There is a preference that specifies that if a character column in a result set is longer than a specified value that the column will be treated as a CLOB. CLOB values are written to files. The preference is set in the Teradata Datatools Preferences > SQL Handling page of the dialog shown when you select the Preferences item in the Windows menu. The value is set in the Teradata tab of the preference page.
The default length is 16,384. If you want results whose column size is larger than that to be displayed in the Result Set Viewer, change that preference's value to something that is larger than the size of the result.
Alternatively, if you expand the Data Source Explorer to the table/view/macro, you can right-click on the object and select the "Show DDL" item from the "Teradata" sub-menu in the context menu. The object's DDL will be shown in a SQL Editor.