MHX changes

Version 1.1.0 of the MHX format has been released. It is in MH svn and hopefully in today's nightly build. I will defer committing it to Blender itself until the bugs have been sorted out.
You will notice several changes when a character is imported into Blender:

• The character is called by his proper name, not just the generic "Human". Spaces in the name is replaced by underscores.
  
• The rig, mesh, clothes etc. belong to a group, named after the character. This is useful for file linking.
  
• The FK/IK and finger control switches don't work. Instead, switching is controlled by custom properties, which can be accessed in the object context when the rig is active.
  

The properties may be called differently in the nightly build. I changed the names to something more readable, but am unsure if the commit was made before the nightly was built.

There are quite a few problems with the current release:

• Changing a property, e.g. an FK/IK switch, does not update the rig immediately. The change only takes place when we move a bone.
  
• There are properties for reparenting the root and gaze bones. Currently they do nothing, because the child-of constraints have been replaced by proper parenting due to a bug in Blender.
  
• It is not possible to do smooth interpolation between FK and IK, because enums are enums. Controlling the switch with a float property is probably better.
  
• Properties do not seem to work with file linking and rig proxifying. I think this is a major misfeature in Blender, bordering on a bug.
  

So this is still at a very experimental stage.

Old mhx files can still be imported with the new importer, but the result is not so good. Joint diamonds are not deleted, and a big box sticks out of the characters behind. This is normally a sign that something went wrong, but here it is just the custom shapes that are visible. Hide layer 20 and everything should still work.

Problems with nightly builds

At the moment, a raid card is misbehaving on my virtualization server. This causes frequent problems with hangs and disruptions, and is generally annoying.

For nightly builds this means they may be updated somewhat erratically. They should update most of the time, but there's no guarrantee.

I have ordered new hardware and hope to fix this soonish. Until then, please be aware that the nightly you download might not be the latest svn version. This is especially important to note when/if you report bugs.

I'll post an update once I have the new server up.

MakeHuman and Povray's Subsurface Scattering

Greetings! Manuel asked me to find some imaging conditions that work well with the new SubSurface Scattering (SSS) effects possible with version 3.7 of the Persistence of Vision Raytracer. MakeHuman will contain a povray exporter. The purposes of these posts-- works in progress-- will be to demonstrate development on MakeHuman and to make a call for the best povray materials for realistic human skin. It has been noted that the subsurface scattering implementation in povray 3.7 is experimental and may change, but I decided to give it a whirl.

First, I imported the SSS parameters for conditions for "Skin1", "Skin2", and "Chicken" from Jensen, et al's paper, A Practical Model for Subsurface Light Transport. These are compared against my accidental choice of parameters and a simple view without SSS. First of all, I was surprised that the "Chicken1" parameters led to such dark meat! Secondly, I note that under these set of conditions, there were both an unseemly highlighting of mesh edges and "blue fingers". This merited further experimentation with the mm_per_unit parameter in the povray code.


In this set, I tried a range of values for mm_per_unit. As one can clearly see, there is no happy medium between highlighting of vertices (prominent in the center of pectoral muscle) and a lack of color in the fingers. There were only values of this parameter where both occurred. Some users may recognize the tile pattern from Christoph Lipka's subsurface.pov file, which comes with povray 3.7.




Here are the latest results. After further experimentation with the mm_per_unit value, I have settled on a value of around 8 and my version of diffuse + SSS. The image below unfortunately took 100 minutes to render. At this time I suppose it could be due to the fact that three models have SSS. I will continue experimentation to search for quality similar to this one with faster render time.



This is my code so far:
material {
texture {
pigment { color rgb 3*< 200/256,134/256,116/256 >}
finish {ambient 0 diffuse 0 specular 0.7882353/2
roughness 0.00286312
subsurface { 3* < 200/256,134/256,116/256>, < 0.013,>}
}
}
interior { ior 1.3 }
}


If you'd like to contribute your own material for fast, realistic skin, please chime in!

Expressions test

Just to show you how expression plugin works.
We are testing it in svn.

Documentation

I have been writing some documentation:
https://sites.google.com/site/makehumandocs/blender-export-and-mhx

Most of the text was copied from my tutorial and only slightly edited, but some parts are new.

Export from MakeHuman
Describes how to design a character in MakeHuman and how to export her as an OBJ, MHX or DAE file. https://sites.google.com/site/makehumandocs/blender-export-and-mhx/export-from-makehuman

Configuration of clothes and proxy export
Apart from the high-poly mesh itself, MakeHuman can export several other things: low-poly versions of the character, clothes, or a cage intended for the meshdeform modifier. This page describes how to configure your export to include only the objects you want.
https://sites.google.com/site/makehumandocs/blender-export-and-mhx/proxy-configu

MHX import into Blender 2.49
The Blender 2.4 series is becoming obsolete and development has stopped. This page describes how to import the mhx file into Blender 2.49 and earlier.
http://sites.google.com/site/makehumandocs/blender-export-and-mhx/blender-export-and-mhx-249.

MHX import into Blender 2.5x
Describes how to import an MHX file into Blender 2.5x. https://sites.google.com/site/makehumandocs/blender-export-and-mhx/mhx-import-in-blender-2-5

Posing with the MHX rig
Describes the rig in the MHX files and how to use it. https://sites.google.com/site/makehumandocs/blender-export-and-mhx/the-mhx-rig

Collada export and import
Describes the rigged characters exported in the DAE format, and how to import them into Blender
https://sites.google.com/site/makehumandocs/blender-export-and-mhx/collada-import

Hair (particles)
Describes how to import particle hair into Blender. https://sites.google.com/site/makehumandocs/blender-export-and-mhx/hair

Mocap tool
Describes how to use the mocap tool to load BVH animations onto the MHX or DAE rigs. https://sites.google.com/site/makehumandocs/blender-export-and-mhx/mocap-tool

Lipsync tool
Describes how to use the lipsync tool to make an MHX character speak. https://sites.google.com/site/makehumandocs/blender-export-and-mhx/lipsync-tool

Making clothes
If you are bored with the clothes that come with MakeHuman and want to design your own, this is the page for you. https://sites.google.com/site/makehumandocs/blender-export-and-mhx/making-clothes