Lines, Polylines and Fills

2D elements are essential in many places through out a BIM project; everything can’t be modeled or derived from a model element. We have several tools to compensate for non-modeled elements, but the three that are most prevalent are the line, polyline and fill tools.

It is critical to know the advantages and disadvantages of each. So here are a few highlights of what each tool can do and where they should and should not be used.


Lines are individual segments. These segments are selected individually, unless grouped. If the line segments are grouped they can not be edited unless grouping is suspended (after selecting the group). Because of this limitation, lines should seldom be used for plan, section or elevation graphics or detail elements. They should never be used where a continuous drafted element with a single line weight is being represented (elevation over drafting for example).

Lines should be used for plan symbols of GDL elements (in the GDL editor), drawing 2d pieces of a GDL element or component, or where any drafted element is a single segment or a multiple line segment which changes line weights along its length or perimeter.

All Edit>Reshape functions work with lines, which makes them preferred over polylines for single segments.

Lines can be consolidated by using the Edit > Reshape > Consolidate Linework function. This will eliminate overlapping lines and convert separate lines along a single vector into a single line segment. Lines can also be converted to polylines by using the Edit > Reshape > Unify function. This will convert any connected line or arc segments into a single polyline element.


Polylines have an advantage over lines, in that they are a continuous vector. This means you can select the entire polyline assembly with a single click. Polylines should be used for any drafted detail element, elevation or section over-drafting or non-modeled plan element or annotation.

Polylines do not work well for plan symbol portions of a GDL object or component. Lines and arcs should be used for this purpose.

Polylines have a few disadvantages. The most prominent two are that the intersect function does not work with polylines (all other reshape function work just as they do with lines), and the line weight needs to be continuous for the entire element.

Polylines can not be consolidated using the Edit > Reshape > Consolidate Linework function. Attempting a polyline consolidation will result in the polylines being converted to individual line & arc segments, which can then be consolidated, then reunified into a single polyline by using the Edit > Reshape > Unify command. Alternatively polylines can be consolidated by selecting and unifying. This will turn overlapping or abutting polylines into a single polyline. If the polyline has arrows they will be turned off once it has ben unified.


Fills with a border pen can be used in details in place of polylines in most cases. The only place polylines should be used in place of fills for details is where the line is not a continuously looped segment. Fills can be used to define the drafted perimeter of an interior elevation, with an integrated mask for cut elements. Fills should not be used to draw the drafted outline of an exterior elevation, however, since these are usually partial segments only.

Fills can be used as GDL plan symbol elements, and should be part of the plan symbol to create a mask ready object, as well as a single click selectable object.

Fills have very limited reshape functions; stretch, resize, split and offset are the only functions that can be applied to fills.

Also worth mentioning for fills is the ability to consolidate fills with the Edit > Reshape > Fill Consolidation function. This feature gives options for unifying overlapping or abutting fill elements.

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