Class TIfcAxis2Placement2D

Unit

Declaration

type TIfcAxis2Placement2D = class(TIfcPlacement)

Description

Location and orientation to place items in a two-dimensional space.

Spec: https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcAxis2Placement2D.htm

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 2838).

Hierarchy

Show Additional Members:

Overview

Methods

Protected function WantsGlobalId: Boolean; virtual;
Protected class function IfcClassName: String; virtual;
Public function BuildNode(const Mapping: TCastleIfcMapping; const ParentProduct: TIfcProduct; const LitAppearance, UnlitAppearance: TAppearanceNode): TAbstractChildNode; virtual;
Public function P(const AxisCoord: T2DAxis): TVector2;
Public procedure GetTransform(out Translation: TVector3; out Rotation: TVector4); override;

Properties

Published property GlobalId: String read FGlobalId write FGlobalId;
Published property LayerAssignment: TIfcPresentationLayerAssignment read FLayerAssignment write FLayerAssignment;
Published property StyledByItem: TIfcStyledItem read FStyledByItem write FStyledByItem;
Published property Location: TIfcPoint read FLocation write FLocation;
Published property RefDirection: TIfcDirection read FRefDirection write FRefDirection;

Description

Methods

Protected function WantsGlobalId: Boolean; virtual;

This item is declared in ancestor TIfcPersistent.

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_types.inc (line 52).

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).

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

This item is declared in ancestor TIfcRepresentationItem.

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

Parameters
ParentProduct
Parent TIfcProduct, to be used with TCastleIfcMapping.ConnectShapeAndProduct call.

It can be Nil (and TCastleIfcMapping.ConnectShapeAndProduct is already prepared to handle it too) if no particular TIfcProduct is parent of this, which (right now) only happens for some internal usage in UpdateCrossSection for throw-away shape instances.

LitAppearance
Appearance that should be used for all shapes created here, if they are supposed to be lit (made of polygons). May be given as Nil.
UnlitAppearance
Appearance that should be used for all shapes created here, if they are supposed to be unlit (made of lines, points). May be given as Nil.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 368).

Public function P(const AxisCoord: T2DAxis): TVector2;

Axes of the created coordinate system. Always normalized and orthogonal.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 2843).

Public procedure GetTransform(out Translation: TVector3; out Rotation: TVector4); override;

This item has no description. Showing description inherited from TIfcPlacement.GetTransform.

Get translation and rotation defined here. Rotation is expressed just like TCastleTransform.Rotation and TTransformNode.Rotation, so it's axis and angle (in radians).

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 2845).

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: TIfcPresentationLayerAssignment read FLayerAssignment write FLayerAssignment;

This item is declared in ancestor TIfcRepresentationItem.

Assignment of the representation item to a single or multiple layer(s). Nil if none.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 374).

Published property StyledByItem: TIfcStyledItem read FStyledByItem write FStyledByItem;

This item is declared in ancestor TIfcRepresentationItem.

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. Nil if none.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 380).

Published property Location: TIfcPoint read FLocation write FLocation;

This item is declared in ancestor TIfcPlacement.

This item has no description.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 2019).

Published property RefDirection: TIfcDirection read FRefDirection write FRefDirection;

Direction of the local X axis. May be Nil.

Source: scene/load/ifc/castleifc_ifc_standard_types.inc (line 2848).


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