Getting Started with _SkinModifier
Last update: June 24, 2005
Email frank@frankladner.com if you have any questions.
Introduction

Tools Used   This tutorial assumes that you have trueSpace (Version 5.1 used here) and SkinModifier (Version 1.23 used here). If you do not have SkinModifier, download the evaluation copy here:
http://ckgamefactory.hp.infoseek.co.jp/tsxe/skinmodi.htm
The unregistered version has limitations, but it costs only $15 to register.
 
 
 
   
What is SkinModifier?   SkinModifier is a trueSpace plugin by CK Game Factory that allows skin deformation using any polyhedron or trueSpace bone object.
 
 
   
   
   
   
   


Setting Up

Load Object   Go ahead and load an object that you would like to use. For our example, I've picked a leg object.

(Download Leg Object)
 
 
 
 
 
 
 
 
 
 
   
Create Bones  

Now add some objects to be used as bones. In this case, I added a box primitive , scaled it, then duplicated it.



(I switched the scene object coloring to yellow to better show the bone objects.)

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   
Name Bones  

Using the Object Info box, give the bone objects a meaningful name.



I like to prefix my bone object names with "m_" to let me know they are modifier objects. Maybe being a programmer also has something to do with my naming-convention habits. :-)

 
 
 
 
 
 
 
 
 
 
   
Load SkinModifier   After you are satisfied with the bone placement, go ahead and load SkinModifier.


 
 
 
 
 
   
Setup SkinModifier   Select your mesh object and click the Edit button on the SkinModifier dialog. You should then see the following:
 
 
 
 
 
 
 
   
  With the mesh object still selected, click the Pick button.
You should now see the object listed in the Skin box. As you can see below, I didn't give my mesh object a descriptive name. :-)
 
   
  Click the Bones button.
 
 
 
 
 
 
 
   
  Select a bone and click the Add button.
 
 
 
 
 
 
 
   
  Do this until all of the bones have been added to the list.
 
   
Vertex Weighting   Click the Target Vertex button.
 
   
  Select a bone from the list.
 
   
  Make sure trueSpace is in Point Edit:Vertices mode and click the Lasso icon.
 
   
  Select the vertices that will be attached to the nearby bone.
 
   
  Click the Get Vertices button.
 
   
  Select the object from the bones list.
 
   
  Adjust the slider until the weight value is 100.
 
   
  Click the Glow Weight button to smooth out the weighting into the neighboring vertices.
 
   
  Repeat the Select Bone->Get Vertices->Adjust Weight procedure for the remaining bones.
   
  Once you are finished with the weighting, move the bone objects around to be sure the skin deforms properly.
   
 
  (NOTE: SkinModifier works with Subdivision Surfaces.)
   
 
   
Conclusion  

When I first tried to use SkinModifier, I was overwhelmed and it took a lot of experimentation before I figured out how things worked. This is a very basic tutorial designed to remove some of the mystery of the plugin.

 

 
 
 
   
Taking it Further   There are some aspects that I didn't cover in an effort to keep things simple.
 
  • PARENTING -If you plan to use basic polyhedron objects as deformers, it would be best to link/parent the bones before attaching a skin to them. This will make animation easier.
  • FACIAL ANIMATION - It is possible to have a single-mesh character with arm/leg animation AND facial animation using this plugin. What makes it ideal for facial animation is the ability to not only effect the mesh by translation, but by scale and rotation. (So you can have an object to control the mouth and eye muscles.
    [Download Screengrab - Download AVI]
  • MOTION STUDIO - Through fiddling around, I have managed to get SkinModifier to work with MotionStudio. The IK would be handled by MotionStudio, and the deformation would be handled by SkinModifier. HOWEVER, there is no real need for this unless you would like to have custom non-MotionStudio bones (ie. for facial animation) attached to the mesh.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   

Well, I guess that's it. Let me know if you have any questions.

frank@frankladner.com