01. Box modelling
"To create the wise stag for The Paper Fox interactive book, I
start by box-modelling in Maya, using reference images for proportions. The models are very low-poly with hardened normals. This helps imitate the flat planes of folded paper, and also allows the models to be used on low-powered mobile platforms."
02. Adding imperfections
"After the main form has been modelled, I spend a great
deal of time adding imperfections. As I’m trying to make the creatures look as though they were created by hand, this is imperative to remove the digital feel. I simply spend time moving, jostling and rotating faces and vertices ever so slightly to ensure that there are no perfect boxes or edges."
"For the texture, I created a coloured set of tiling paper
textures using a base texture I created from royalty-free paper images. To finish the illusion of paper, I created a normal map using Nvidia’s Photoshop plug-in from the same set of textures. This normal map creates the subtle detailing that helps sell the hand-crafted look."
"Rendering the animal portrait, I use V-Ray with a very simple lighting set-up. For a fill light, I use one large V-Ray area light and cast it downward. A smaller area light is used for a key light to illuminate the opposing side, which pops the character from the drop sheet."
05. Render passes
"I also render out a Z-depth pass, which I use in Photoshop to create the depth of field. This is crucial for creating the illusion of realism. Once I’ve balanced the levels and sharpened the image, I create a combined flattened layer Ctrl+Shift+Alt+E and apply a layer mask. I use the exported Z-depth pass for the layer mask and then use a Lens Blur to add depth of field."
06. Multiple textures
"As I’m also using these creatures in a game engine, using multiple tiling textures isn’t optimal. To get around this, I use Maya to bake the multiple textures into one texture sheet. For each shader applied, I set the ambient colour to V:1.000 and the diffuse value to 0.000. This ensures no lighting information will be baked in. I then use mental ray’s batch bake to bake the light and colour into one map."
"In addition to colour, I bake an occlusion pass and a directional light pass. The latter is to give the character a subtle gradient and helps to create the illusion of sun light. I create a directional light pointing downward and bake out an only-light pass. In Photoshop I apply this pass at the top of the stack and set it to Soft Light."
08. UV image
"To complete the in-game character texture, I add some wear to the edges and corners to enhance the illusion of paper craft. An exported image of the UVs is perfect for this. I lay the UV image at the top of the stack, apply a layer mask and invert it so none of the UV lines is showing. Using a soft brush, I then brush back the mask on the corners and harder edges. Voila! Wear and tear. And we’re done, and I love it."
Jeremy Kool is a 3D artist and graphic designer from Melbourne, Australia.
This article orginally appeared in 3D World issue 173.