Anchor is a Grouping node that can contain most nodes. When the user selects any of the geometry contained by the Anchor node, the browser either jumps to another viewpoint (similar to HTML bookmark) or else loads content (such as X3D, an image or HTML) specified by the url field. Newly loaded content completely replaces current content, if the value of parameter field indicates using the same window.

The Anchor node belongs to the Networking component and requires at least level 2, its default container field is children. It is available since VRML 2.0 and from X3D version 3.0 or higher.


+ X3DNode
  + X3DChildNode
    + X3DGroupingNode (X3DBoundedObject)*
      + Anchor (X3DUrlObject)*

* Derived from multiple interfaces.


SFNode [in, out] metadata NULL [X3DMetadataObject]

Information about this node can be contained in a MetadataBoolean, MetadataDouble, MetadataFloat, MetadataInteger, MetadataString or MetadataSet node.


SFString [in, out] description “”

Author-provided prose that describes intended purpose of the url asset.


  • Many XML tools substitute XML character references for special characters automatically if needed within an attribute value (such as & for & ampersand character, or " for “ quotation-mark character).

SFBool [in, out] load TRUE

The load field has no effect, Anchor operation is only triggered by user selection.

MFString [in, out] url [ ] [URI]

Address of replacement world, or #ViewpointDEFName within the current scene, or alternate Web resource, activated by the user selecting Shape geometry within the Anchor children nodes.


  • Jump to a world’s internal viewpoint by appending viewpoint name (for example, #ViewpointName, someOtherCoolWorld.x3d#GrandTour).
  • Jump to a local viewpoint by only using viewpoint name (for example, #GrandTour).
  • Binding a different Viewpoint triggers an isBound event that can initiate other user-arrival reactions via event chains to interpolators or scripts.
  • MFString arrays can have multiple values, so separate each individual string by quote marks “” “” “etc.”
  • Alternative XML encoding for quotation mark “ is " (which is an example of a character entity).
  • Can replace embedded blank(s) in url queries with %20 for each blank character.
  • Pop up a new window with url value as follows: “‘somePage.html’,’popup’,’width=240,height=240’);location.href=’HelloWorld.x3d’”
  • X3D Scene Authoring Hints, urls


  • Strictly match directory and filename capitalization for http links! This is important for portability. Some operating systems are forgiving of capitalization mismatches, but http/https url addresses and paths in Unix-based operating systems are all case sensitive and intolerant of uppercase/lowercase mismatches.

MFString [in, out] parameter [ ]

If provided, parameter tells the X3D player where to to redirect the loaded url.


  • Set parameter value as target=_blank to load the target url into a new browser frame.
  • Set parameter value as target=frame_name to load target url into another browser frame.
  • MFString arrays can have multiple values, so separate each individual string by quote marks. “” “” “etc.” Interchange profile
  • This field may be ignored, applying the default value regardless.

SFTime [in, out] autoRefresh 0 [0,∞)

The [autoRefresh field has no effect, Anchor operation is only triggered by user selection.

SFTime [in, out] autoRefreshTimeLimit 3600 [0,∞)

The [autoRefreshTimeLimit field has no effect, Anchor operation is only triggered by user selection.

SFBool [in, out] visible TRUE

Whether or not renderable content within this node is visually displayed.


  • The visible field has no effect on animation behaviors, event passing or other non-visual characteristics.
  • Content must be visible to be collidable and to be pickable.

SFBool [in, out] bboxDisplay FALSE

Whether to display bounding box for associated geometry, aligned with world coordinates.


  • The bounding box is displayed regardless of whether contained content is visible.

SFVec3f [ ] bboxSize -1 -1 -1 [0,∞) or −1 −1 −1

Bounding box size is usually omitted, and can easily be calculated automatically by an X3D player at scene-loading time with minimal computational cost. Bounding box size can also be defined as an optional authoring hint that suggests an optimization or constraint.


  • Can be useful for collision computations or inverse-kinematics (IK) engines.
  • Precomputation and inclusion of bounding box information can speed up the initialization of large detailed models, with a corresponding cost of increased file size.
  • X3D Architecture, 10.2.2 Bounding boxes /Part01/components/grouping.html#BoundingBoxes
  • X3D Architecture, 10.3.1 X3DBoundedObject /Part01/components/grouping.html#X3DBoundedObject

SFVec3f [ ] bboxCenter 0 0 0 (-∞,∞)

Bounding box center accompanies bboxSize and provides an optional hint for bounding box position offset from origin of local coordinate system.


MFNode [in] addChildren

Input field addChildren.

MFNode [in] removeChildren

Input field removeChildren.

MFNode [in, out] children [ ] [X3DChildNode]

Grouping nodes contain an ordered list of children nodes.


  • Each grouping node defines a coordinate space for its children, relative to the coordinate space of its parent node. Thus transformations accumulate down the scene graph hierarchy.
  • InputOnly MFNode addChildren field can append new X3DChildNode nodes via a ROUTE connection, duplicate input nodes (i.e. matching DEF, USE values) are ignored.
  • InputOnly MFNode removeChildren field can remove nodes from the children list, unrecognized input nodes (i.e. nonmatching DEF, USE values) are ignored.
  • X3D Architecture 10.2.1 Grouping and children node types /Part01/components/grouping.html#GroupingAndChildrenNodes




See Also

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