Chapter 21. Particle Systems

Articulation and Skinning

Skinning utilizes two elements: a mesh for the figure's skin (or clothes) and an articulated bone model. The vertices of the skin mesh are connected to bone contact points by weights, which specify how the skin adjusts as the bones move.

Salamander

Mark McKay has released a skeletal animation and skinning system as part of his unfinished but useful Salamander Project (https://skinandbones.dev.java.net/). Salamander offers keyframe interpolation and multiple animation tracks based on the Maya trax editor.

Skinning VRML loader

Seungwoo Oh has developed a VRML loader that can handle motion data (rotations and translations) and supports geometry skinning (http://vr.kaist.ac.kr/~redmong/research.htm). He has utilized this for clothing human figures with convincing results. His site includes Java 3D loaders and articles explaining the concepts behind his software.

H-Anim skinning

A skinned mesh system, derived from the H-Anim specification, is part of Xj3D, a toolkit for VRML 97 and X3D content written in Java (http://www.xj3d.org/). There's a version for Aviatrix3D, a Java scene graph API over the top of JOGL (http://aviatrix3d.j3d.org/). There's no Java 3D version at the moment (December 2004).

M3G

Java 2 Micro Edition (J2ME) has an optional 3D graphics API package called M3G. It's an interesting mix of high-level and low-level 3D graphics features, developed under JSR 184. M3G includes a SkinnedMesh class, which represents a skeletally polygon mesh.

A good source of M3G documentation, articles, and examples is Nokia (http://www.forum.nokia.com/java/jsr184) and the web site for this book (http://fivedots.coe.psu.ac.th/~ad/jg/), which includes five chapters about M3G (including one on skinning).

Magicosm

The Magicosm site has a page about its skin and bone capabilities (http://www.cosm-game.com/dev_skinbones.php), posted in 2001. The Skeleton class contains a hierarchy of bones and stores active, queued, and dormant animations. A Skin is a collection of sinews, vertices and triangles. Each Sinew object forms a bond between a vertex and a bone with a weight.