With OlapCube writer, you can easily group column values into categories.

For example, you can easily create a Continent dimension, even if you only have a country column in your database.

Step 1
Click the country column in the preview window

Step 2
Select "Transform or convert this field"

Step 3
Click Add and select "Group values into categories"

Step 4
Select European countries and drag them in the right window

Step 5
Rename the category

Step 6
Click OK when you are done

Step 7
Rename the new column

The new column is now available, you can use it as any other column to create new dimensions

The red color indicates that it is a transformed column.