Enhance TransformControls.js to center gizmo on geometry bounding box

Hi,

Not sure it is the right to ask for an enhancement.

I have used transformControls.js (V64) and realised that the gizmo is centered on local position (0,0,0) of an element. This doesn’t mean it is the real center of the mesh.

I have modified the update function, may be you could add it to the next release.

this.update = function () {

    if ( scope.object === undefined ) return;

    //sho - Add 2014/01/10 - set the gizmo at object center.
    if (scope.object.geometry) {
        if (!scope.object.geometry.boundingBox)
            scope.object.geometry.computeBoundingBox();
        worldPosition.getPositionFromMatrix(scope.object.matrixWorld);
        worldPosition.add(scope.object.geometry.boundingBox.center());
    } else {
        worldPosition.getPositionFromMatrix(scope.object.matrixWorld);
    }
    /******/        

    /*scope.object.updateMatrixWorld();
    worldPosition.setFromMatrixPosition( scope.object.matrixWorld );
    worldRotation.setFromRotationMatrix( tempMatrix.extractRotation( scope.object.matrixWorld ) );*/

    camera.updateMatrixWorld();
    camPosition.setFromMatrixPosition( camera.matrixWorld );
    camRotation.setFromRotationMatrix( tempMatrix.extractRotation( camera.matrixWorld ) );

    scale = worldPosition.distanceTo( camPosition ) / 6 * scope.size;
    this.position.copy( worldPosition )
    this.scale.set( scale, scale, scale );

    eye.copy( camPosition ).sub( worldPosition ).normalize();

    if ( scope.space == "local" )
        this.gizmo[_mode].update( worldRotation, eye );

    else if ( scope.space == "world" )
        this.gizmo[_mode].update( new THREE.Euler(), eye );

    this.gizmo[_mode].highlight( scope.axis );

}

[mstrater]

“If you want the conceptual origin to be somewhere other than (0, 0, 0), put your mesh in an Object3D and translate it such that the conceptual center of the mesh is at the Object3D’s origin.” This advice saved me so much time. Thanks a ton eric-wieser!

[eric-wieser]

@SebastienHo: Why is the center of the bounding box more meaningful than the origin of the mesh? The origin won’t move with respect to the rest of the model after an .applyMatrix, but the center of a bounding box will, due to it being axis aligned. If you want the conceptual origin to be somewhere other than (0, 0, 0), put your mesh in an Object3D and translate it such that the conceptual center of the mesh is at the Object3D’s origin.