Overview of our B-Mesh modeling approach. (a) Specifying the skeleton and key-balls at the nodes by users; (b) creating inbetween-balls (in gray) by interpolating the key-balls; (c) generating an initial mesh; (d) subdividing the mesh (c); (e) evolving the mesh (d); (f) obtaining the final mesh with more subdivision and evolution.
Motivation
In game and movie industries, highly detailed 3D shapes are becoming commonplace. In general, modeling such shapes involve a lot of work and effort for both designer and artists. The whole modeling process is complex, and usually needs a cooperation of using a group of packages. A common but not a fixed workflow is as follows:
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sketch three-view drawings, make a coarse polygonal mesh (3ds Max,Maya, etc.)
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import into the sculpting package to carve (ZBrush, Mudbox)
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make a UV map of the base mesh (UVLayout, Unfold3D, etc.)
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paint colors and textures (Bodypaint, Photoshop, etc.), and
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make some maps such as displacement, normal, ambient occlusion and so on (xNormal, ZBrush, Maya, etc.).
Recently, digital sculpting modeling becomes a fairly popular approach for creating 3D character shapes with scan quality geometric detail in game and movie industry and has emerged to be a new trend to 3D modeling like ZBrush. The sculpting modeling considers a 3D modeling as a coarse-to-fine procedure. First, a coarse base mesh is generated to represent the rough structure of the shape. The user then imports the base mesh into some sculpting package, subdivides it into higher resolution, and adds geometric and texture details (see the following figures). The two phases can be iterative during the modeling process (also watch a video on YouTube) .
See the video on Youtube about how ZBrush generates the base mesh using ZSpheres and sculpts details (or here) on the base mesh. Sculpting geometric details on the base mesh requires a quad mesh with good edge flows. However, ZSpheres does not meet these requirement quite well.
Abstract
This paper presents a
novel modeling system, called B-Mesh, for generating base meshes
of 3D articulated shapes. The user only needs to draw a one-dimensional
skeleton and to specify key balls at the skeletal nodes. The system then
automatically generates a quad dominant initial mesh. Further
subdivision and evolution are performed to refine the initial mesh and
generate a quad mesh which has good edge flow along the skeleton
directions. The user can also modify and manipulate the shape by editing
the skeleton and the key balls and can easily compose new shapes by
cutting and pasting existing models in our system. The mesh models
generated in our system greatly benefit the sculpting operators for
sculpting modeling and skeleton-based animation.
An example modeling sequence. (a) Skeletal shape balls in different stages of modeling; (b) the final skeletal shape balls; (c) the result mesh.
Some models generated by our B-Mesh system
We would like to thank
the anonymous reviewers for their valuable comments and suggestions.
Ligang Liu is supported by the 973 National Key Basic Research
Foundation of China (No. 2009CB320801) and the joint grant of the
National Natural Science Foundation of China and Microsoft Research Asia
(No. 60776799).
title = {B-Mesh: A Modeling System for Base Meshes of 3D Articulated Shapes},
author = {Zhongping Ji and Ligang Liu and Yigang Wang}
journal = {Computer Graphics Forum (Proceedings of Pacific Graphics)},
volume = {29},
number = {7},
pages = {2169-2178},
year = {2010}
}