Since v4.3.0

Introduction

Void areas or cut outs in shapes can be used in several ways. Most typical use case include possibility to create a cut out in bigger shape like room, so that certain construction elements like pillars can be omitted. 

This also creates on opportunity to easily place another shape in a cutout, for example to place "room within a room".

System supports import of void areas from various formats like IFC or Fi2. The void contour will be processed and represented as a "cut out" in the master shape. 

As a result, we can address problems described earlier:

• a shape with a void area or cutout will exist and be possible to select only in area actually covered by this shape

• there will be no overlapping colors / shades in normal view and when the presentation is applied

• we will be able to accurately detect smaller shape within a bigger shape, e.g. for purpose of move management (moving objects from one room to another)

A sample 3D representation of a "room within a room":

Open

A 2D representation of room polygons:

Open

Note that with support for Void areas, the inner shape is independent and its not covered by the bigger outer shape.

Handling Void areas during import

Various formats have their own representation of void areas. 

Currently import of the following formats supports void areas:

• IFC 

• FI2 v 1.22 (IFC based)

• FI2 v 1.3 (FI2 proprietary geometries)

Adding Void areas manually

In cases where object overlay is added manually and void areas must be added the process can be controlled manually.

This process has several limitations:

• A shape with void (empty) area is a single combined shape

• Merging several shapes together to create a void area is non-reversible process.
  What does it mean? When we combine a room polygon with a round pillar represented by circle element, both shapes will be converted into single path element.
  Should you need to extract these shapes, they will remain as individual shapes but as paths and not the original type. This might have implications how the extracted shapes can be edited. 

• If two shapes are combined, and they only partially overlap, only the part where they overlap will create a void area. Overlapping part (void) is indicated by the arrow:
  
  

Creating room with voids

First, draw a shape of the room, polygon or rectangle:

Then, draw shapes covering areas that should be used as voids. Use regular shapes that best suite void areas: rectangle, polygon, circle or ellipse.

Note: the order in which the shapes are drawn is not relevant.

Select all shapes - room and pillars, then right click on main shape and select Combine contours function:

This will process your shapes by converting them into single path element. Overlapping parts will create void areas.

 Important: From the selection, the shape that is right clicked will be used as a primary shape:

• Primary shape will have "positive" area value

• All secondary shapes will have a "negative" area value, regardless if they overlap with primary shape or not.

Sample shape is colored in light blue with red outline to illustrate where the void areas are located:

 Now one can add additional shapes by drawing new void area and using Combine contours function or Extract contours split shapes back to individual entities: