Class TIfcPolygonalFaceSet

Unit

Declaration

type TIfcPolygonalFaceSet = class(TIfcTessellatedFaceSet)

Description

Tessellated face set with all faces being bound by polygons. This is what is most commonly referred to as "a mesh" in 3D.

Spec: https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcPolygonalFaceSet.htm

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 850).

Hierarchy

Show Additional Members:

Overview

Methods

Protected class function IfcClassName: String; virtual;
Protected function WantsGlobalId: Boolean; override;
Public constructor Create(AOwner: TComponent); override;
Public destructor Destroy; override;
Public function BuildNode(const Mapping: TCastleIfcMapping; const ParentProduct: TIfcProduct; const LitAppearance, UnlitAppearance: TAppearanceNode): TAbstractChildNode; override;

Properties

Published property GlobalId: String read FGlobalId write FGlobalId;
Published property LayerAssignment: TIfcPresentationLayerAssignmentList read FLayerAssignment;
Published property StyledByItem: TIfcStyledItem read FStyledByItem write FStyledByItem;
Published property Coordinates: TIfcCartesianPointList3D read FCoordinates write FCoordinates;
Published property HasColours: TIfcIndexedColourMap read FHasColours write FHasColours;
Published property HasTextures: TIfcIndexedTextureMapList read FHasTextures;
Published property Closed: Boolean read FClosed write FClosed default false;
Published property Faces: TIfcIndexedPolygonalFaceList read FFaces;
Published property PnIndex: TIntegerList read FPnIndex;

Description

Methods

Protected class function IfcClassName: String; virtual;

This item is declared in ancestor TIfcPersistent.

Name for the IFC standard, used in IFC files. By default, this is just ClassName with prefix 'T' removed.

Source: scene/load/ifc/castleifc_ifc_types.inc (line 56).

Protected function WantsGlobalId: Boolean; override;

This item has no description. Showing description inherited from TIfcPersistent.WantsGlobalId.

If True, instances of this class will have GlobalId auto-assigned at saving, and they will be saved as part of the "data" list in IFC JSON files.

Strictly following the spec, this should be only defined for TIfcRoot, because only IfcRoot has GlobalId. In reality, we need GlobalId at TIfcPersistent to load some files, and we sometimes need WantsGlobalId = True to save some files.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 856).

Public constructor Create(AOwner: TComponent); override;

This item has no description.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 858).

Public destructor Destroy; override;

This item has no description.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 859).

Public function BuildNode(const Mapping: TCastleIfcMapping; const ParentProduct: TIfcProduct; const LitAppearance, UnlitAppearance: TAppearanceNode): TAbstractChildNode; override;

This item has no description. Showing description inherited from TIfcRepresentationItem.BuildNode.

Build a node to display this using Castle Game Engine. Returns Nil if not possible / not implemented.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 860).

Properties

Published property GlobalId: String read FGlobalId write FGlobalId;

This item is declared in ancestor TIfcPersistent.

Globally unique identifier for the object instance.

Note: Not declared as TGUID, because TGUID cannot be published, but also we don't really need it: for our purposes, this identifier is just an arbitrary string.

Note: IFC 4.3 specification puts this only at IfcRoot, not at every IFC class. But testcase https://github.com/buildingsmart-community/Community-Sample-Test-Files/blob/main/IFC%204.0.2.1%20(IFC%204)/ISO%20Spec%20archive/wall-with-opening-and-window.json (from IFC 4.0) shows this can be present at any IFC class, in particular TIfcGeometricRepresentationContext.

In fact, TIfcGeometricRepresentationContext needs to have GlobalId to be successfully saved (avoid recursively trying to serialize it) in some cases. We indicate such classes with WantsGlobalId.

IFC JSON documentation says this, which seems to (unfortunately it is not unambiguous enough...) allow this at any IFC class: "Whereas the globalId attribute is only available to those elements that are descendent of the IfcRoot entity in the EXPRESS schema, we encourage a broader use of this globalId, to enable referencing between objects in a JSON file when useful.".

Source: scene/load/ifc/castleifc_ifc_types.inc (line 79).

Published property LayerAssignment: TIfcPresentationLayerAssignmentList read FLayerAssignment;

This item is declared in ancestor TIfcTessellatedItem.

Assignment of the representation item to a single or multiple layer(s).

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 541).

Published property StyledByItem: TIfcStyledItem read FStyledByItem write FStyledByItem;

This item is declared in ancestor TIfcTessellatedItem.

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 547).

Published property Coordinates: TIfcCartesianPointList3D read FCoordinates write FCoordinates;

This item is declared in ancestor TIfcTessellatedFaceSet.

Ordered list of Cartesian points.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 835).

Published property HasColours: TIfcIndexedColourMap read FHasColours write FHasColours;

This item is declared in ancestor TIfcTessellatedFaceSet.

Reference to the indexed colour map providing the corresponding colour RGB values to the faces.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 839).

Published property HasTextures: TIfcIndexedTextureMapList read FHasTextures;

This item is declared in ancestor TIfcTessellatedFaceSet.

Reference to the indexed texture map providing the corresponding texture coordinates to the vertices.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 843).

Published property Closed: Boolean read FClosed write FClosed default false;

Indication whether the face set is a closed shell (TRUE) or an open shell (FALSE).

IFC spec says: If omitted no such information can be asserted. For our implementation, "no such information can be asserted" means it shall be treated as an open shell, so we don't introduce a 3rd state.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 870).

Published property Faces: TIfcIndexedPolygonalFaceList read FFaces;

List of polygonal faces.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 873).

Published property PnIndex: TIntegerList read FPnIndex;

The list of integers defining the locations in the IfcCartesianPointList3D to obtain the point coordinates for the indices at the indexed polygonal faces. If the PnIndex is not provided the indices at the indexed polygonal faces point directly into the IfcCartesianPointList3D.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 879).


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