getPreviousSkinnedPosition( builder ) {

		const skinnedMesh = builder.object;

		if ( this.previousBoneMatricesNode === null ) {

			skinnedMesh.skeleton.previousBoneMatrices = new Float32Array( skinnedMesh.skeleton.boneMatrices );

			this.previousBoneMatricesNode = referenceBuffer( 'skeleton.previousBoneMatrices', 'mat4', skinnedMesh.skeleton.bones.length );

		}

		return this.getSkinnedPosition( this.previousBoneMatricesNode, positionPrevious );

	}
Computes the transformed/skinned vertex position of the previous frame.

@param {NodeBuilder} builder - The current node builder.
@return {Node<vec3>} The skinned position from the previous frame.