It can be added to the scene or as a child of any Object3D.
It is specially useful for debugging purpose.
The Trident name is borrowed from the Away3D project http://away3d.com/livedocs/3.6.0_lib/away3d/primitives/Trident.html

Still there are some new objects created per frame there.

Just a single callback is now passed  to loader.load( "scene.js", callbackFinal ) - callback which is called when everything from the scene was already loaded.

If you want to use also callbacks for initialization of procedural synchronously created elements, you can set property of loader:

loader.callbackSync = function( result ) { ... }

If you want to get callback for load progress, set:

loader.callbackProgress = function( progress, result ) { ... }

Also added per scene creation of collision systems (it used to be singleton).

Only the first update should set the last updated timestamp, not constructor.

Added .name and .getChildByName( "objectName", doRecurse ) to Object3D. Added so scene-loader fills in .name property.

It works both for JSON models and textures. Handling of every asynchronously loaded asset triggers calls to "onLoadStart" and "onLoadComplete" callbacks.

Fleshed out RollCamera: refactored code out of example, add more keyboard controls, API and made it framerate independent.

Updated Loader and SceneLoader to automatically set "material.transparent" flag for materials with opacity < 1.

Updated builds.

Added handling of shadow geometry to scene loader. Made default light and camera option to Blender scene exporter. Made shadow geometry invisible in exported scene.

Added .castShadow to DirectionalLight and check this in the renderStencilShadow function in WebGLRenderer. castShadow is set to false by default. Updated examples.

Added functions for getPosition(), getColumnX(), getColumnY() and getColumnZ() to easier access the different components of the matrix.