ifcopenshell.api.void

Create void relationships between openings and physical elements

An opening is a special element (created using ifcopenshell.api.root.create_entity()) that may then be used to create voids in other elements (such as walls and slabs). These voids may then be filled with doors, trapdoors, skylights, and so on.

Submodules

• ifcopenshell.api.void.add_filling
• ifcopenshell.api.void.add_opening
• ifcopenshell.api.void.remove_filling
• ifcopenshell.api.void.remove_opening

Package Contents

ifcopenshell.api.void.add_filling(file: ifcopenshell.file, opening: ifcopenshell.entity_instance, element: ifcopenshell.entity_instance) → ifcopenshell.entity_instance

Fill an opening with an element

Physical elements may have openings in them. For example, a wall might have an opening for a door. That opening is then filled by the door. This indicates that when the door moves, the opening will move with it. Or if the door is removed, then the opening may remain and need to be filled.

Parameters:

• opening (ifcopenshell.entity_instance) – The IfcOpeningElement to fill with the element.

• element (ifcopenshell.entity_instance) – The IfcElement to be inserted into the opening.

Returns:

The new IfcRelFillsElement relationship

Return type:

ifcopenshell.entity_instance

Example:

# A bit of preparation, let's create some geometric contexts since
# we want to create some geometry for our wall and opening.
model3d = ifcopenshell.api.context.add_context(model, context_type="Model")
body = ifcopenshell.api.context.add_context(model,
    context_type="Model", context_identifier="Body", target_view="MODEL_VIEW", parent=model3d)

# Create a wall
wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")

# Let's use the "3D Body" representation we created earlier to add a
# new wall-like body geometry, 5 meters long, 3 meters high, and
# 200mm thick
representation = ifcopenshell.api.geometry.add_wall_representation(model,
    context=body, length=5, height=3, thickness=0.2)
ifcopenshell.api.geometry.assign_representation(model,
    product=wall, representation=representation)

# Place our wall at the origin
ifcopenshell.api.geometry.edit_object_placement(model, product=wall)

# Create an opening, such as for a service penetration with fire and
# acoustic requirements.
opening = ifcopenshell.api.root.create_entity(model, ifc_class="IfcOpeningElement")

# Let's create an opening representation of a 950mm x 2100mm door.
# Notice how the thickness is greater than the wall thickness, this
# helps resolve floating point resolution errors in 3D.
representation = ifcopenshell.api.geometry.add_wall_representation(model,
    context=body, length=.95, height=2.1, thickness=0.4)
ifcopenshell.api.geometry.assign_representation(model,
    product=opening, representation=representation)

# Let's shift our door 1 meter along the wall and 100mm along the
# wall, to create a nice overlap for the opening boolean.
matrix = np.identity(4)
matrix[:,3] = [1, -.1, 0, 0]
ifcopenshell.api.geometry.edit_object_placement(model, product=opening, matrix=matrix)

# The opening will now void the wall.
ifcopenshell.api.void.add_opening(model, opening=opening, element=wall)

# Create a door
door = ifcopenshell.api.root.create_entity(model, ifc_class="IfcDoor")

# Let's create a door representation of a 950mm x 2100mm door.
representation = ifcopenshell.api.geometry.add_wall_representation(model,
    context=body, length=.95, height=2.1, thickness=0.05)
ifcopenshell.api.geometry.assign_representation(model,
    product=door, representation=representation)

# Let's shift our door 1 meter along the wall and 100mm along the
# wall, which lines up with our opening.
matrix = np.identity(4)
matrix[:,3] = [1, .05, 0, 0]
ifcopenshell.api.geometry.edit_object_placement(model, product=door, matrix=matrix)

# The door will now fill the opening.
ifcopenshell.api.void.add_filling(model, opening=opening, element=door)

ifcopenshell.api.void.add_opening(file: ifcopenshell.file, opening: ifcopenshell.entity_instance, element: ifcopenshell.entity_instance) → ifcopenshell.entity_instance

Create an opening in an element

It is often necessary to cut out openings in elements like walls and slabs to make space to insert doors, windows, and other services that go through these penetrations.

Whereas it is possible to simply draw the wall as a rectangle with a hole in it for the opening, often these openings have specific meanings. For example, an opening might be filled with a window, and so when the window moves, the opening should move with it. Alternatively, the opening itself might have fire or acoustic requirements, such that any service or equipment passing through that space must also comply with those requirements. For these types of semantic openings, you should have a distinct opening element which voids your regular element. For example, your wall will still be a rectangular prism with no hole in it, and a separate opening element will have a box representing the extents of the opening for a window. The opening element will automatically perform a geometric boolean operation to cut out the wall’s geometry.

Whenever you have an opening in you project, you should determine whether or not the opening is semantic (i.e. should be represented by a distinct opening object) or non-semantic (i.e. should simply be booleaned or be part of the shape of the object).

Parameters:

• opening (ifcopenshell.entity_instance) – The IfcOpeningElement to cut out the element.

• element (ifcopenshell.entity_instance) – The IfcElement to insert the opening into.

Returns:

The new IfcRelVoidsElement relationship

Return type:

ifcopenshell.entity_instance

Example:

# A bit of preparation, let's create some geometric contexts since
# we want to create some geometry for our wall and opening.
model3d = ifcopenshell.api.context.add_context(model, context_type="Model")
body = ifcopenshell.api.context.add_context(model,
    context_type="Model", context_identifier="Body", target_view="MODEL_VIEW", parent=model3d)

# Create a wall
wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")

# Let's use the "3D Body" representation we created earlier to add a
# new wall-like body geometry, 5 meters long, 3 meters high, and
# 200mm thick
representation = ifcopenshell.api.geometry.add_wall_representation(model,
    context=body, length=5, height=3, thickness=0.2)
ifcopenshell.api.geometry.assign_representation(model,
    product=wall, representation=representation)

# Place our wall at the origin
ifcopenshell.api.geometry.edit_object_placement(model, product=wall)

# Create an opening, such as for a service penetration with fire and
# acoustic requirements.
opening = ifcopenshell.api.root.create_entity(model, ifc_class="IfcOpeningElement")

# Let's create an opening representation of a 950mm x 2100mm door.
# Notice how the thickness is greater than the wall thickness, this
# helps resolve floating point resolution errors in 3D.
representation = ifcopenshell.api.geometry.add_wall_representation(model,
    context=body, length=.95, height=2.1, thickness=0.4)
ifcopenshell.api.geometry.assign_representation(model,
    product=opening, representation=representation)

# Let's shift our door 1 meter along the wall and 100mm along the
# wall, to create a nice overlap for the opening boolean.
matrix = np.identity(4)
matrix[:,3] = [1, -.1, 0, 0]
ifcopenshell.api.geometry.edit_object_placement(model, product=opening, matrix=matrix)

# The opening will now void the wall.
ifcopenshell.api.void.add_opening(model, opening=opening, element=wall)

ifcopenshell.api.void.remove_filling(file: ifcopenshell.file, element: ifcopenshell.entity_instance) → None

Remove a filling relationship

If an element is filling an opening, this removes the relationship such that the opening and element both still exist, but the element no longer fills the opening.

Parameters:

element (ifcopenshell.entity_instance) – The element filling an opening.

Returns:

None

Return type:

None

Example:

# Create a wall
wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")

# Create an opening, such as for a service penetration with fire and
# acoustic requirements.
opening = ifcopenshell.api.root.create_entity(model, ifc_class="IfcOpeningElement")

# Create a door
door = ifcopenshell.api.root.create_entity(model, ifc_class="IfcDoor")

# The door will now fill the opening.
ifcopenshell.api.void.add_filling(model, opening=opening, element=door)

# Not anymore!
ifcopenshell.api.void.remove_filling(model, element=door)

ifcopenshell.api.void.remove_opening(file: ifcopenshell.file, opening: ifcopenshell.entity_instance) → None

Remove an opening

Fillings are retained as orphans. Voided elements remain. Openings cannot exist by themselves, so not only is the opening relationship removed, the opening is also removed.

Parameters:

opening (ifcopenshell.entity_instance) – The IfcOpeningElement to remove.

Returns:

None

Return type:

None

Example:

# Create an oprhaned opening. Note that an orphaned opening is
# invalid, as an opening can only exist when voiding another
# element.
opening = ifcopenshell.api.root.create_entity(model, ifc_class="IfcOpeningElement")

# Remove it. This brings us back to a valid model.
ifcopenshell.api.void.remove_opening(model, opening=opening)