Exercise: Creating a User Defined Roof Panel

The following is one way to place a user defined cross bar panel along the surface using a point grid on the surface and a intermediary ShapeGrid.

Click the (Point) tool in the Place Geometry ribbon toolbar. In the model view, the point is attached to the mouse pointer.
Press and hold <Ctrl> before clicking on the BSplineSurface (bsplineSurface1). Click to place it anywhere on the surface. A new node point5 is added to the Graph. It's technique is set to ByUVParametersOnSurface, and one of its required inputs Surface is automatically connected to the overall node on bsplineSurface01.
In the Graph, right click on point5 and select Edit. The Node Properties dialog opens.
Replace the current U and V required input values with Series functions to obtain a grid of points rather then a single point.
1. Enter Series(0.0,1.0,0.05) for the U input.
2. Enter Series(0.0,1.0,0.1) for the V input.
You will see a diagonal set of points. In order to get the full grid of points you need to toggle the replication option of the point.
In the Graph, right click on point5 and select Switch Replication Style. The diagonal set of points is changed to a full grid of points.
Note: Next create a Polygon.ByPointGrid based on the point grid just created. This grid serves as the placement method for a diagonal cone grid of the roof.
In the Node Types dialog, select the Polygon node and set its technique to ByPointGrid.
In the Graph, draw a wire from the polygon1's Points required input to the overall node on point05.
Record User Changes into Transaction file.