In this chapter the base mesh is explained. The base mesh is the standard body mesh used in MakeHuman.

MakeHuman displays a visible mesh on the screen but inside it works with additional geometry to allow a better handling of clothes, to have helping geometry for bones etc.

Basemesh1.png Basemesh1.png

The complete mesh has an exact number of vertices and each vertex has a number, starting with number 0 to 13379 for the body and then continues to 19157 for the helper-geometry.

These are current number ranges:

name start end purpose
body 0 13379 visible mesh
helper-tongue 13380 13605 weighting and deforming the tongue
joints 13606 14597 used to connect bones to
helper-x-eye 14598 14741 weighting and deforming the eyes
helper-x-eyelashes-y 14742 14991 weighting and deforming the eyelashes
helper-lower-teeth 14992 15059 weighting and deforming the lower teeth
helper-upper-teeth 15060 15127 weighting and deforming the upper teeth
helper-genital 15128 15327 weighting and deforming the male genitals
helper-tights 15328 18001 weigthing and deforming clothes near the body
helper-skirt 18002 18721 weighting and deforming a skirt
helper-hair 18722 19149 weighting and deforming the hair
ground 19150 19157 calculation of difference between root-bone and ground

Internally that means: when a target e.g. resizes an arm, then also the tight-helper must be deformed. If the arm will be longer, some of the cubes for the joints will also be moved.

For a better overview: these are the components of the helper.

Basemesh2.png Basemesh2.png

The joints are a special helper. These are tiny cubes placed (mostly) inside the body. Each cube has 8 vertices, the median is used e.g. as a start- or end-point for a bone. This allows to determine the bone position inside the body. The following overview shows the joints of the upper body

Basemesh3.png Basemesh3.png

Some bones do not end in such a cube. The reason: bones can use each vertex available in helper-geometry or body. For the default skeleton there are two different other methods used:

(1) red dots: for e.g. the lowerarm01 and -02 bone the connecting point in the middle is calculated by simply summarizing the start and the end point of the complete lower arm. So this is a special case where rotation only is allowed in radial direction like in reality (simulating the bones ulna and radius of the lower arm).

(2) blue and yellow dots: The bones end directly on a vertex of the skin. Especially for facial expressions the face-bones (simulating muscles) use vertices on the skin directly. The yellow dots are use for the tongue, they end on the tongue helper.

Facebones.png Facebones.png

A few sentences for the standard skeleton here. For most bones the purpose in MakeHuman is simple to understand. The root bone is used to place character and it does not deform parts of the skin. Most of the other bones do. They can rotate and will influence the skin. A little more complicated is the facial region. Here some bones can be rotated and also translated to another location (painted in yellow in the demo picture). All “helper bones” have no own weight groups, they are only used to guide the other bones. And we have four bones which should be left untouched. These I call constant bones.

So in theory when using this in e.g. Blender, the face could be reduced to less bones, but then the location of the yellow bones must be part of the parameters saved. This could be an optimization when you do an animation later.