A TransformNode is an object that is not rendered but can be used as a center of transformation. This can decrease memory usage and increase rendering speed compared to using an empty mesh as a parent and is less complicated than using a pivot matrix.
The TransformNode can be used as a center of transformation (CoT) for a mesh and some lights and cameras by acting as a parent to them increasing versatility.
Remember that, as with any parent, transformations are relative to the frame of reference of the parent. In all of the following Playgrounds the purple sphere is created only to show the TransformNode position.
As a Center of Rotation
Set a TransformNode as a parent then rotate the TransformNode.
//create a Center of Transformationvar CoT = new BABYLON.TransformNode("root");box.parent = CoT; //apply to Box
The light blue cylinder is an additional stationary object to show that the camera is moving.
For those examples stating a dummy camera a black sphere is used to show the intended path of the camera in the Playground that follows it. The purple ray shows the direction of view of the camera and the tube an indication of the view covered by the camera.
Arc Rotate Camera
The center of transformation is placed at the target position of the arc rotation camera.Rotating Dummy Camera Rotating Arc Camera
Target position moved by moving center of tranformation.Rotating Dummy Camera Rotating Arc Camera
Camera position moved relative to center of transformation just changes the distance between the camera and target.Rotating Dummy Camera Rotating Arc Camera
The arrow keys will allow you to move camera position (reminder to click on canvas area before using keys).Rotating Universal Camera 1
You can also have a universal camera rotating in orbit around a target and move it with keys.Rotating Universal Camera 2
Those lights that have a position can use a TransformNode.
Point LightRotating Point Light Rotating Spot Light
As a Center of Translation or Position
When you move a center of transformation anything that is parented to it will move with it.
When you transform an object with a center of transformation as parent then that transformation takes place relative to the frame of reference of the center of transformation.
In the example below you can see that the simple movement given by
box.position.x += 0.01;
takes place along the rotating x axis of the center of transformation.Box Translation
Moving cameras and lights work in the same way.
As a Center of Enlargement
Obviously scaling has no effect on lights or cameras. Scaling takes place relative to the frame of reference of the center of enlargement.Box Scaling