BIM Covering


Window
Pipe
BIM

BIM Covering

Menu location
3D/BIM → Covering
Workbenches
BIM
Default shortcut
C V
Introduced in version
1.2
See also
None

Description

The BIM Covering tool creates a parametric object representing a surface finish applied to a planar face. Typical use cases include floor tiling, wall cladding, ceiling finishes, roofing, skirting boards, and any other repeating surface material.

Depending on the selected Finish Mode, the object produces either individual 3D tile geometry with real joint gaps, a flat parametric representation, or a technical hatch pattern. All modes update a set of Quantity Take-Off properties on every recompute, making the object useful for material schedules and cost estimation regardless of the level of geometric detail chosen.

The Covering object is semantically equivalent to the IFC IfcCovering class. Its DataPredefinedType property maps directly to the IFC subtypes (FLOORING, CLADDING, ROOFING, MOLDING, SKIRTINGBOARD, CEILING, WRAPPING), making it suitable for BIM workflows that require IFC export.

Usage

From a pre-selection

  1. Select one or more faces or objects in the 3D View or the model tree. Multiple faces across different objects are allowed; the command will create one Covering per selected item in a single batch operation.
  2. Invoke the command via the Covering toolbar button or the (3D/BIM → Covering) menu entry.
  3. The task panel opens with the selection already populated. Adjust parameters and press OK.

From the command (no pre-selection)

  1. Invoke the Covering command with nothing selected.
  2. The task panel opens with the Pick button active (indicated by the red recording icon and the label "Picking…"). The 3D View is in selection mode.
  3. Click a face or object to select it as the base:
    • Objects can be selected from the model tree by a single click.
    • To select a specific face from the 3D View, click the object once to select it, then click the face a second time. Clicking an edge on the first or second click will clear the selection rather than adding to it.
    • Hold Ctrl while clicking to accumulate multiple items before confirming.
  4. Adjust parameters and press OK to create the Covering(s).

Edit mode

Double-click an existing Covering object in the model tree to reopen the task panel in edit mode. All parameters can be changed. To reassign the base face, activate the Pick button and select a new face.

Undo behavior

The undo behaviour differs between creation modes:

Finish Modes

The Finish Mode controls how the covering geometry is generated and displayed. It can be changed at any time without losing other settings.

All modes except Hatch Pattern support texture mapping via the Visuals task panel section.

Solid Tiles

Individual 3D tiles are generated with real joint gaps between them via boolean subtraction. Each tile is a separate solid extruded to the specified thickness. This mode is the most geometrically accurate and produces the most informative Quantity Take-Off data (including individual tile counts and waste). It is also the less performant. It is best suited for close-up renders, detailed drawings, and material schedules.

Performance note: When the tile count exceeds 10,000 or the joint width is less than 0.1 mm, the engine automatically switches to analytical mode: the geometry falls back to a single monolithic solid, while tile counts and areas are still computed mathematically. A warning is printed to the Report View when this occurs. At counts above 100,000, layout lines are also hidden.

Parametric Pattern

A grid of tile layout lines is drawn on a single flat slab without extruding individual tiles. The slab thickness is controlled by the Tile Thickness parameter. This mode is lighter to display and recompute than Solid Tiles, making it suitable for large-scale views, preliminary layouts, or performance-sensitive models.

Monolithic

A single continuous surface is produced with no tile subdivisions. The tile dimensions define the texture repeat period only. This mode is intended for seamless or near-seamless materials such as plaster, paint, polished concrete, carpet, or linoleum, where individual unit boundaries are absent or irrelevant.

Hatch Pattern

A 2D CAD-style hatch pattern is applied to a single flat slab using a standard .PAT pattern file. This mode is intended for technical drawings and plans. A PAT file and pattern name must be specified; FreeCAD's bundled FCPAT.pat is offered as the default. Texture mapping is not available in this mode.

Options

BIM Covering task panel

The task panel is divided into three collapsible sections that logically group all controls.

Covering Definition

Control Description
Base The face or object the covering is applied to. Click Pick to change it interactively.
Mode Selects the geometry generation strategy (see Finish Modes above).
Thickness Extrusion depth of each tile (or slab thickness in non-Solid modes).
Length Tile body length along the U axis.
Width Tile body width along the V axis.
Joint Width Width of the gap between tiles.
Stagger Running bond offset: None (stacked), 1/2, 1/3, 1/4, or Custom. The Custom option enables a free offset input.
Continue When checked, pressing OK creates the covering and immediately resets the panel for a new one, without closing the task panel.

Layout and Boundaries

Control Description
Rotation Rotates the entire tile grid around the face normal.
Alignment Preset or Custom grid anchor (see Alignment section below).
U Offset Manual offset of the grid origin along the face U axis. Active only in Custom alignment mode. FreeCAD expressions are supported.
V Offset Same as above, for V axis.
Border Setback Shrinks the tiling area inward from the face boundary by the given distance. Useful to keep tiles away from skirting boards or other perimeter elements.

Visuals

Control Description
Texture Image An image file mapped continuously onto the covering surface. The file is embedded in the document.
Texture Scale Multiplier applied to the texture repeat in U and V independently. Values above 1.0 stretch the texture; values below 1.0 compress it.

Alignment

The Alignment setting controls where the tile grid is anchored relative to the base face boundary.

Preset alignments

Five presets are available: Center, Top Left, Top Right, Bottom Left, Bottom Right.

For corner presets, the named corner of the lead tile is aligned to the named corner of the face. For instance, Top Right places the top-right corner of the lead tile flush with the top-right corner of the face. The lead tile is a conceptual anchor, not a physical tile: it's the one used to define the alignment. For Center, the center of the lead tile is placed at the center of the face.

Corner names follow the face orientation: on a rotated surface, Top Right refers to the top-right corner of the face itself, not of the viewport or the world. Grout joints at the aligned corner extend outward beyond the face boundary. For the Center preset, the center of a single tile is placed at the face center.

Custom alignment

Selecting Custom activates the U Offset and V Offset input fields, which shift the grid origin by an arbitrary distance along the face coordinate axes. The offset is measured from the face centre. FreeCAD parametric expressions are accepted in both fields, allowing the offset to be driven by a VarSet, spreadsheet cell or a model dimension.

Interactive

The Interactive button (available in Custom mode) enters an interactive grid placement mode. While active, a tile preview tracks the mouse cursor in the 3D View, anchored at its bottom-left corner.

Setting the origin: click any point in the 3D View — typically a vertex of the base face — to set the grid origin at that point. The click ends the interactive session: the U offsed, V offset and rotation fields are updated automatically and the alignment is switched to Custom. To exit without placing, press Esc.

Rotating the grid: optionally, before clicking to confirm the origin, press R to rotate the tile wireframe clockwise by one step, or Shift+R to rotate counter-clockwise. The Rotation field updates live with each keypress. The step size defaults to 15° and can be changed by setting ViewPickRotationStep in the View tab of the object's properties panel.

If a rotation has been entered manually in the Rotation field before activating Interactive, the wireframe will start at that angle rather than zero. It is not possible to manually enter the rotation in the input field during interactive mode.

Match Working Plane

The Match Working Plane button sets the grid origin to the projection of the current FreeCAD working plane origin onto the base face, expressed as a U/V offset. This allows the tile grid to be aligned to a known reference point in the model.

Texture Mapping

Texture images are mapped onto the covering surface using a continuous linear projection with a period equal to TileLength + JointWidth in U and TileWidth + JointWidth in V. The texture repeats seamlessly across the entire surface with no gaps.

Quantity Take-Off

The following properties are computed automatically on every recompute and can be read from the object's Data panel or referenced in a FreeCAD spreadsheet:

Property Description
DataCountFullTiles Number of tiles that fit entirely within the face boundary.
DataCountPartialTiles Number of tiles that are cut by the boundary.
DataHoleAreas The individual area of each hole in the base face, in mm², sorted by size (largest first).
DataNetArea Surface area of the base face (the area to be covered).
DataGrossArea Total area of material consumed, including partial tiles ordered as full units.
DataOuterArea The area enclosed by the outer boundary of the base face, ignoring any holes.
DataWasteArea GrossArea − NetArea: the area of cut-off material that is discarded.
DataTotalJointLength Sum of all joint centre-line lengths.
DataPerimeterLength Perimeter of the base face.

Physical vs analytical calculation

When the tile count is within normal limits (up to 10,000 tiles) and the joint width is at least 0.1 mm, quantities are derived from the actual computed geometry (physical mode): tile counts are obtained by counting the resulting solids, and areas are measured from their faces. This is the most accurate method.

When the tile count exceeds 10,000, or the joint is too narrow for stable boolean operations (< 0.1 mm), the engine switches to analytical mode: the geometry falls back to a single monolithic solid, and counts and areas are computed mathematically from the tile dimensions and face area. The QTO values remain valid and usable in schedules; only the 3D representation is simplified.

At counts above 100,000 (extreme count mode), layout lines are additionally hidden to prevent display freezes.

A status message is printed to the Report View whenever the engine falls back from physical to analytical mode.

Using QTO data in a spreadsheet

To reference a Covering's quantities in a FreeCAD spreadsheet, use the standard expression syntax. For example, to read the net area of a covering named Covering: 

=Covering.NetArea

Known limitations

  1. Because Coin3D (FreeCAD's 3D renderer) does not support discontinuous texture mapping, it is not possible to leave the joint region genuinely empty in the texture. As a workaround, the texture origin is shifted by half the joint width, so the tile body is centered within its period and the texture image is centered on the physical tile. Since the joint region cuts off only the outermost border of the texture on each side, this is visually indistinguishable from a true gap for typical joint widths (5–10 mm with 300 mm tiles). For cases where the joint is large relative to the tile — and the cut-off edge is noticeable — the joint appearance can be incorporated directly into the texture image itself, for example by including a grout-coloured border.
  2. Texture images will not be present in Covering objects exported in IFC format. This is a limitation of the exporter, not of the Covering object. It is also unclear how well supported this feature is in most IFC viewers.
  3. At this time, and unlike other BIM objects, Additions and Subtractions support is not yet implemented.
  4. If both the Covering and its base object (e.g. Slab) are moved, the final position of the Covering will not be correct. If a relocation is desired, either the base or the Covering can be moved, but only one at a time. This is a limitation of all BIM objects, but on Covering objects it's easier to select both at the same time, since the base is deliberately not shown as the Covering's child on the Tree View.

Properties

Data

An Arch Covering object shares the common properties and behaviors of all Arch Components.

Covering

Tiles

Boundaries

Quantities

Visual

Pattern

IFC

IFC Attributes

View

Standard FreeCAD ViewProvider properties (Visibility, ShapeColor, Transparency, etc.) are inherited from the Arch Component base class.

Interactive

Notes

Scripting

Covering objects can be created from Python using Arch.makeCovering(). 

import Arch

# Create a covering on a specific face of an object
box = FreeCAD.ActiveDocument.addObject("Part::Box", "Box")
FreeCAD.ActiveDocument.recompute()

covering = Arch.makeCovering((box, ["Face6"]))
covering.TileLength = 300.0   # mm
covering.TileWidth  = 300.0
covering.TileThickness = 10.0
covering.JointWidth = 5.0
covering.TileAlignment = "Center"
covering.FinishMode = "Solid Tiles"

FreeCAD.ActiveDocument.recompute()

The makeCovering function accepts:

Window
Pipe
BIM
BIM
User documentation