What is ZENN Fur?
ZENN Fur is a new system based on Zelos Fur for creating digital fur.
It is capable of creating digital animals covered entirely with fur such as gorillas, tigers, lions, etc. A fur strand is represented by a thin curve. If a body mesh were to be covered completely with fur, millions to tens of millions of strands would be needed, and the size of the data would usually come to be hundreds of gigabytes per animal. ZENN enables artists to create digital fur by handling heavy data efficiently.
· In order to plant fur strands on the given body surface, follicles are first distributed.
· There are several methods to distribute points on the given body surface.
· ZENN provides several sampling methods such as Monte Carlo sampling, adapting Poisson disk sampling, etc.
· Artists can control follicle density locally using user-defined paint maps.
· Through ZENN’s multiple sampling options, it is possible to manage large fur data efficiently and appropriately for diverse situations.
· ZENN’s fur data can be rendered using RenderMan. (Currently, ZENN only supports RenderMan.)
· ZENN provides RenderMan DSO (Dynamic Shared Object) that converts ZENN cache files into RiCurve primitives at rendering phase.
· ZENN cache files store vertex positions, texture coordinates, colors, indices, widths, etc., which allow artists to create various render results through shaders.
· It is important to calculate fur color and shadows for visual feedback.
· This is because it is otherwise impossible to distinguish individual fur strands in the rendered image.
· However, as it takes too long to receive visual feedback from a photo realistic renderer, ZENN provides real-time preview through the Maya viewport as a solution.
Fast & Stable Simulation
· ZENN provides a fast and stable simulator based on PBD (Position Based Dynamics).
· Nowadays, PBD is one of the most popular algorithms to simulate physically-based motions, because it is easy to apply constraints and is numerically stable.
· However, PBD has some disadvantages. For example, stiffness is dependent on time step size and the number of iterations.
· Thus, ZENN can be used in conjunction with other simulators such as Maya nHair to simulate fur strands.