Freeform Architectural Cast Glass. Nathan Allan designers were looking to create a new Architectural Cast Glass. As a result, our Freeform Series glass was formed. In contrast to our Classic Textures which are relatively opaque, Freeform Series glass is clear. However, the surface of this glass is deep, lofty, and 3-Dimensinal. As a result, protruding Convex shapes are formed on the front surface of each panel. But on the contrary, a Concave depression is formed on the back side. For these reasons, this Architectural Cast Glass is like no other.