// create your text field and set its content.
var t:TextField = new TextField();
t.text = "Hello world!";
// create a BitmapData of your wished width and height
var bitmap:BitmapData = new BitmapData(100,100);
// Fill bmp with the content of your TextField.
//It's as if you took a picture of t.
bitmap.draw(t);
// Create a material with the resulting BitmapData and you can use it on any DisplayObject3D!
var material:BitmapMaterial = new BitmapMaterial(bitmap);
material.smooth = true;
material.doubleSided = true;
// Create cube
var cube:Cube = new Cube(material)