The simple answer is Yes:
However, it makes the Graph Builder and the data table more complex. If using the Gantt Chart Addin as the structures model, you would have to add a new column to contain the new end data for each different type of fill pattern you want. And then the Graph Builder chart would have to be modified to add in a new Bar with the range set for the correct starting column to the new column in the data table that was created for the new category. Below is the code for the graph builder with just one new fill patter type. I changed the fill pattern, but it could have just as easily have been a solid pattern with just a different color.
Graph Builder(
Size( 907, 626 ),
Show Control Panel( 0 ),
Variables(
X( :Start Date ),
X( :donedate, Position( 1 ) ),
X( :End Date, Position( 1 ) ),
X( :Extended Date, Position( 1 ) ),
Y( :Task, Order By( :Start Date, Descending, Order Statistic( "Mean" ) ) )
),
Elements(
Bar( X( 1 ), X( 3 ), Y, Legend( 32 ), Bar Style( "Range" ) ),
Bar( X( 1 ), X( 2 ), Y, Legend( 20 ), Bar Style( "Range" ) ),
Bar( X( 1 ), X( 4 ), Y, Legend( 44 ), Bar Style( "Range" ) )
),
SendToReport(
Dispatch(
{},
"Start Date",
ScaleBox,
{Min( 3442521600 ), Max( 3487017600 ), Interval( "Month" ), Inc( 1 ),
Minor Ticks( 0 ), Label Row( Label Orientation( "Angled" ) )}
),
Dispatch(
{},
"Task",
ScaleBox,
{Label Row(
{Show Major Ticks( 0 ), Set Font( "Tahoma" ), Set Font Size( 11 )}
)}
),
Dispatch(
{},
"400",
ScaleBox,
{Legend Model(
32,
Level Name( 0, "Incomplete" ),
Properties( 0, {Fill Color( 77 )} )
), Legend Model(
20,
Level Name( 0, "Complete" ),
Properties( 0, {Fill Color( 53 )} )
), Legend Model(
44,
Properties( 0, {Fill Color( 74 ), Fill Pattern( "hatch heavy" )} )
)}
),
Dispatch( {}, "graph title", TextEditBox, {Set Text( "Gantt Chart" )} ),
Dispatch( {}, "X title", TextEditBox, {Set Text( "Date" )} ),
Dispatch( {}, "Y title", TextEditBox, {Set Text( "Tasks" )} )
)
);
And this is the data table with the modification I had to make to allow for the new bar category. Notice the new column called Extended Date. In the model I am proposing, additional columns like Extended Date would have to be added.
Jim