Class AcDbBlockReference

Represents a block reference entity in AutoCAD.

A block reference is used to place, size, and display an instance of the collection of entities within the block table record that it references. Block references allow you to reuse complex geometry by referencing a block definition multiple times with different positions, rotations, and scales.

Example

// Create a block reference
const blockRef = new AcDbBlockReference("MyBlock");
blockRef.position = new AcGePoint3d(10, 20, 0);
blockRef.rotation = Math.PI / 4; // 45 degrees
blockRef.scaleFactors = new AcGePoint3d(2, 2, 1); // 2x scale

// Access block reference properties
console.log(`Block name: ${blockRef.blockTableRecord?.name}`);
console.log(`Position: ${blockRef.position}`);
console.log(`Rotation: ${blockRef.rotation}`);

Hierarchy (View Summary)

Constructors

constructor

Accessors

attrs blockTableRecord color database geometricExtents layer lineStyle lineType linetypeScale lineWeight normal objectId ownerId position rgbColor rotation scaleFactors transparency type visibility

Methods

close draw getAttr getAttrWithoutException getLayerColor setAttr subGetGripPoints subGetOsnapPoints transformBy triggerModifiedEvent

Constructors

constructor

  • new AcDbBlockReference(blockName: string): AcDbBlockReference

  • Creates a new block reference entity.

    This constructor initializes a block reference with the specified block name. The position is set to the origin, rotation to 0, normal to Z-axis, and scale factors to 1.

    Parameters

    • blockName: string

      The name of the block table record to reference

    Returns AcDbBlockReference

    Example

    const blockRef = new AcDbBlockReference("MyBlock");
    blockRef.position = new AcGePoint3d(5, 10, 0);
    blockRef.rotation = Math.PI / 6; // 30 degrees

Accessors

attrs

blockTableRecord

  • get blockTableRecord(): undefined | AcDbBlockTableRecord

  • Gets the block table record referenced by this block reference.

    The referenced block table record contains the entities that the block reference will display.

    Returns undefined | AcDbBlockTableRecord

    The block table record, or undefined if not found

    Example

    const blockRecord = blockRef.blockTableRecord;
    if (blockRecord) {
      console.log(`Block name: ${blockRecord.name}`);
    }

color

database

  • get database(): AcDbDatabase

  • Gets the database in which this object is resident.

    When an object isn't added to a database, this property returns the current working database. After it is added to a database, it will be set automatically. You should never set this value manually.

    Returns AcDbDatabase

    The database this object belongs to

    Example

    const db = obj.database;
  • set database(db: AcDbDatabase): void

  • Sets the database for this object.

    This is typically set automatically when the object is added to a database. Manual setting should be avoided unless you know what you're doing.

    Parameters

    Returns void

    Example

    obj.database = myDatabase;

geometricExtents

  • get geometricExtents(): AcGeBox3d

  • Gets the geometric extents (bounding box) of this block reference.

    This method calculates the bounding box by transforming the geometric extents of all entities in the referenced block according to the block reference's position, rotation, and scale factors.

    Returns AcGeBox3d

    The bounding box that encompasses the entire block reference

    Example

    const extents = blockRef.geometricExtents;
    console.log(`Block bounds: ${extents.minPoint} to ${extents.maxPoint}`);

layer

  • get layer(): string

  • Gets the name of the layer referenced by this entity.

    Returns string

    The layer name

    Example

    const layerName = entity.layer;
  • set layer(value: string): void

  • Sets the name of the layer for this entity.

    Parameters

    • value: string

      The new layer name

    Returns void

    Example

    entity.layer = 'MyLayer';

ProtectedlineStyle

  • get lineStyle(): AcGiLineStyle

  • Gets the line style for this entity.

    This method returns the line style based on the entity's linetype and other properties.

    Returns AcGiLineStyle

    The line style object

    Example

    const lineStyle = entity.lineStyle;

lineType

  • get lineType(): string

  • Gets the name of the line type referenced by this entity.

    Returns string

    The linetype name

    Example

    const lineType = entity.lineType;
  • set lineType(value: string): void

  • Sets the name of the line type for this entity.

    Parameters

    • value: string

      The new linetype name

    Returns void

    Example

    entity.lineType = 'DASHED';

linetypeScale

  • get linetypeScale(): number

  • Gets the line type scale factor of this entity.

    When an entity is first instantiated, its line type scale is initialized to an invalid value. When the entity is added to the database, if a linetype scale has not been specified for the entity, it is set to the database's current line type scale value.

    Returns number

    The linetype scale factor

    Example

    const scale = entity.linetypeScale;
  • set linetypeScale(value: number): void

  • Sets the line type scale factor for this entity.

    Parameters

    • value: number

      The new linetype scale factor

    Returns void

    Example

    entity.linetypeScale = 2.0;

lineWeight

  • get lineWeight(): number

  • Gets the line weight used by this entity.

    Returns number

    The line weight value

    Example

    const weight = entity.lineWeight;
  • set lineWeight(value: number): void

  • Sets the line weight for this entity.

    Parameters

    • value: number

      The new line weight value

    Returns void

    Example

    entity.lineWeight = 2;

normal

objectId

  • get objectId(): string

  • Gets the object ID.

    AutoCAD uses 64-bit integers to represent handles, which exceed the maximum integer value of JavaScript. Therefore, strings are used to represent object handles.

    Returns string

    The object ID as a string

    Example

    const id = obj.objectId;
    console.log(`Object ID: ${id}`);
  • set objectId(value: string): void

  • Sets the object ID.

    Parameters

    • value: string

      The new object ID

    Returns void

    Example

    obj.objectId = 'new-object-id';

ownerId

  • get ownerId(): string

  • Gets the object ID of the owner of this object.

    Returns string

    The owner object ID

    Example

    const ownerId = obj.ownerId;
  • set ownerId(value: string): void

  • Sets the object ID of the owner of this object.

    Parameters

    • value: string

      The new owner object ID

    Returns void

    Example

    obj.ownerId = 'parent-object-id';

position

rgbColor

  • get rgbColor(): number

  • Gets the RGB color of this entity after converting color index.

    This method handles the conversion of color indices (including ByLayer and ByBlock) to actual RGB colors. It resolves layer colors and block colors as needed.

    Returns number

    The RGB color value as a number

    Example

    const rgbColor = entity.rgbColor;
    console.log(`RGB: ${rgbColor.toString(16)}`);

rotation

  • get rotation(): number

  • Gets the rotation value of the block reference.

    The rotation value is relative to the X axis of a coordinate system that is parallel to the OCS of the block reference, but has its origin at the position point of the block reference. The rotation axis is the Z axis of this coordinate system with positive rotations going counterclockwise when looking down the Z axis towards the origin.

    Returns number

    The rotation value in radians

    Example

    const rotation = blockRef.rotation;
    console.log(`Rotation: ${rotation} radians (${rotation * 180 / Math.PI} degrees)`);
  • set rotation(value: number): void

  • Sets the rotation value of the block reference.

    Parameters

    • value: number

      The new rotation value in radians

    Returns void

    Example

    blockRef.rotation = Math.PI / 4; // 45 degrees

scaleFactors

transparency

  • get transparency(): number

  • Gets the transparency level of this entity.

    Returns number

    The transparency value (0-1, where 0 is opaque and 1 is fully transparent)

    Example

    const transparency = entity.transparency;
  • set transparency(value: number): void

  • Sets the transparency level of this entity.

    Parameters

    • value: number

      The transparency value (0-1, where 0 is opaque and 1 is fully transparent)

    Returns void

    Example

    entity.transparency = 0.5; // 50% transparent

type

  • get type(): string

  • Gets the type name of this entity.

    This method returns the entity type by removing the "AcDb" prefix from the constructor name.

    Returns string

    The entity type name

    Example

    const entity = new AcDbLine();
    console.log(entity.type); // "Line"

visibility

  • get visibility(): boolean

  • Gets whether this entity is visible.

    Returns boolean

    True if the entity is visible, false otherwise

    Example

    const isVisible = entity.visibility;
  • set visibility(value: boolean): void

  • Sets whether this entity is visible.

    Parameters

    • value: boolean

      True to make the entity visible, false to hide it

    Returns void

    Example

    entity.visibility = false; // Hide the entity

Methods

close

  • close(): void

  • Closes the object.

    All changes made to the object since it was opened are committed to the database, and a "closed" notification is sent. This method can be overridden by subclasses to provide specific cleanup behavior.

    Returns void

    Example

    obj.close();

draw

getAttr

  • getAttr(attrName: string): any

  • Gets the value of the specified attribute.

    This method will throw an exception if the specified attribute doesn't exist. Use getAttrWithoutException() if you want to handle missing attributes gracefully.

    Parameters

    • attrName: string

      The name of the attribute to retrieve

    Returns any

    The value of the specified attribute

    Throws

    When the specified attribute doesn't exist

    Example

    try {
      const value = obj.getAttr('objectId');
    } catch (error) {
      console.error('Attribute not found');
    }

getAttrWithoutException

  • getAttrWithoutException(attrName: string): any

  • Gets the value of the specified attribute without throwing an exception.

    This method returns undefined if the specified attribute doesn't exist, making it safer for optional attributes.

    Parameters

    • attrName: string

      The name of the attribute to retrieve

    Returns any

    The value of the specified attribute, or undefined if it doesn't exist

    Example

    const value = obj.getAttrWithoutException('optionalAttribute');
    if (value !== undefined) {
      // Use the value
    }

ProtectedgetLayerColor

  • getLayerColor(): null | AcCmColor

  • Gets the color of the layer this entity belongs to.

    This method retrieves the color from the layer table for the layer this entity belongs to.

    Returns null | AcCmColor

    The layer color, or undefined if the layer doesn't exist

    Example

    const layerColor = entity.getLayerColor();

setAttr

subGetGripPoints

  • subGetGripPoints(): AcGePoint3d[]

  • Gets the grip points for this entity.

    Grip points are the control points that can be used to modify the entity. This method should be overridden by subclasses to provide entity-specific grip points.

    Returns AcGePoint3d[]

    Array of grip points as 3D points

    Example

    const gripPoints = entity.subGetGripPoints();

subGetOsnapPoints

  • subGetOsnapPoints(
        osnapMode: AcDbOsnapMode,
        gsSelectionMark: number,
        pickPoint: AcGePoint3d,
        lastPoint: AcGePoint3d,
        snapPoints: AcGePoint3d[],
    ): void

  • Gets the object snap points for this entity.

    Object snap points are the points that can be used for precise positioning when drawing or editing. This method should be overridden by subclasses to provide entity-specific snap points.

    Parameters

    Returns void

    Example

    const snapPoints: AcGePoint3d[] = [];
    entity.subGetOsnapPoints(AcDbOsnapMode.Endpoint, 0, pickPoint, lastPoint, snapPoints);

transformBy

  • transformBy(matrix: AcGeMatrix3d): this

  • Transforms this entity by the specified matrix.

    This method applies a geometric transformation to the entity. Subclasses should override this method to provide entity-specific transformation behavior.

    Parameters

    Returns this

    This entity after transformation

    Example

    const matrix = AcGeMatrix3d.translation(10, 0, 0);
    entity.transformBy(matrix);

triggerModifiedEvent

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