Scaling a Stroke Object
Flash CS4 Tutorial
How to Scale a Stroke Object with or without Scaling the Line in Flash
Stroke objects can be created with the Pen tool, Pencil tool and Line tool. When you first create the object it has a stroke, but no fill. If you attempt to scale your object with the Free Transform tool, Properties panel, Subselection tool or Transform panel the line weight never changes. However if you want the line weight to scale as you enlarge the object it must first be converted to a symbol.
Create a stroke based object with the Pen tool.
Select the object and convert it to a Movie Symbol (F8)(Modify > Convert to Symbol).
With the symbol selected, choose the Free Transform tool (q key).
Scale the object by clicking and draging the transform corner boxes and the line weight increases.
Another Approach to Object Scaling
In this example you can also set the Pen tool to draw lines that don't scale. First select the Pen tool, then open the Properties panel. From the Scale pull down menu, choose None.
Now when the object is converted to a Movie Symbol and scaled, the line weight remains the same.