As the title says this was done in Vue 4.2. All the birds are AlphaPlanes, as can be done in ZBrush with the difference being that in Vue the image is created on a withe background and the then same image is made black on a white background. In ZBrush the image is created on a black Background then applied using Plane3D with transparent turned on in the textures menu. from this you can use make 3D to create some interesting images.
Thanks for looking,
Stay healthy,
Deevee,
Joe. 
