Rigging & Weighting

The Blender Weighting Tools (2.68)

Blender provides a collection of weight tools. And Avastar adds even some more. Most tools are available from Weight Paint mode. And some of Avastar’s buttons are just convenience additions so that you can “find all at one place”. However we have used this redundancy only very sparingly to avoid confusion. This chapter gives a brief overview of the available tools.

The weight Tools are mainly available from 4 locations in the Blender UI:

• Tool Shelf
• Properties sidebar
• Object Data properties (Vertex Groups list)
• Modifier Stack

Many options are also available from various locations in the popup menus. And we also have keyboard shortcuts for some of the more commonly used tools.

Tool Shelf panels (weight Paint Mode)

Most tools for weight Painting are found in the tool Shelf when you are in weight Paint mode. The functions and options are found in several Tool Shelf Panels:

• Brush (different ways to manually apply weights to mesh surfaces)
• Stroke (physical properties of your brush)
• Curve (shape of the Bruish tip)
• Weight Tools (Collection of various useful tools supporting)
• Options (actually tool settings)

Brush

Blender provides a couple of paint brush presets for various purposes:

• Add: to add weight
• Subtract: to remove weight
• Draw: to paint with a defined Weight value
• Blur: to smooth weight transitions
• Lighten: to add weight up to the given value (higher weights are not affected)
• Darken: to remove weight up to a certain value (lower weights are not affected)
• Multiply: to multiply the weights by a given factor (useful for applying very subtle changes in weighting)

You can use all preset brushes for your work and you even can add your own brushes with your preferred settings (You can store your own frequently used brushes within your custom startup.blend file)

The most important parameters for brushes are Weight, Radius (size) and Strength. You find even more parameters in the Stroke panel and in the Curve panel (see Tool Shelf, below the brush panel)

Weight Tools

Blender provides a set of weight helper tools for various purposes. The tools are all collected in the weight tools panel. Some of the tools can work an a set of weight groups:

• Normalize
• Invert
• Clean
• Levels
• Transfer weights
• Limit total

These tools also provide a Subset parameter (in the Operator panel, displayed after the tool is called, available with Blender 2.68) with following options:

• Active Group
• Selected Pose Bones
• Deform pose Bones
• All Groups

The weight tools are reworked and will be improved for Blender 2.68

Hint: The Blend tool only works when “Vertex selection masking for painting” is enabled. Otherwise the tool button is greyed out.

Weight Tool Options

The Options modify the overall brush behaviour. The most commonly used options are:

• Spray: to constantly draw (opposed to drawing one stroke per mouse click)
• Restrict: to only paint on vertices which already are weighted in the active weight group. (No new weights are created, only existin weights modified)
• x-mirror: to draw symmetrical. Note the this only works when the character symmetry plane is z-y (character looks into y direction)
• Show Zero weights: To display unreferenced and zero weighted areas in black (by default)

Normalize

If a subset is selected: For each vertex of the mesh the sum of all used weights for that vertex will be 1.0

Subset: defines which groups are affected.

Lock Active: Keep all weights of the active group untouched and recalculate the weights of all other selected groups.

Mirror

Note: If you want to create a mirrored weight group, then you will first create a copy of the current bone group, then rename the weight group to the name of the bone on the opposite side, and finally perform the Mirror tool. (See below for an alternative provided by Avastar.

Mirror Weights:

Flip Group names:

All Groups:

Invert

Replaces each Weight of the selected weight group by

1.0 – weight.

Examples:

• original 1.0 converts to 0.0
• original 0.5 remains 0.5
• original 0.0 converts to 0.0

Note: Please see how the parameter setting changes the behaviour.

Subset: defines which groups are affected.

Add verts: Adds Zero verts for unreferenced verts before conversion takes place.

Remove verts: Remove Zero weighted Verts from weight Group after Conversion has been done.

Clean

Subset: defines which groups are affected.

Limit: defines the minimum value that a weight must have in order to be kept in the weight group.

Keep Single: Guarantee that for each weighted vertex at least one weight will be kept regardless of the weight value.

Levels

Adds an offset and a scale to all weights of the selected Weight Groups. with this tool you can raise or lower the overall “heat” of the weight group.

Note: No weight will ever be set to values above 1.0 or below 0.0 regardless of the settings.

Subset: defines which groups are affected.

Offset: A value between -1 and +1 will be added to each weight. However the tool guarantees that all weights remain in the allowed range (Values are clamped to [0.1])

Gain: A value in the range [0, 10] used as multiplier for each weight. However the tool guarantees that all weights remain in the allowed range (Values are clamped to [0.1])

Blend

Hint: this tool only works in vertex select mode.

Factor: A value in the range [0,1] which defines the width of the blend area

Transfer weights

Subset: defines which groups are affected.

Method:

• Nearest vertex in face
• Nearest Face
• Nearest Vertex
• Vertex Index

Replace:

• All
• Empty

Limit

Hint: The tool can only work reasonably when more than one weight group is selected.

Subset: defines which groups are affected.

Limit: Maximum number of allowed weight groups per vertex. Typical value for game engine: 4 (also used as default in Blender)

Fix Deforms

Distance: defines which groups are affected. [-10, 10]

Strenght: [-2, 2]

Change Sensitivity: [0.05, 1]

Weight Gradient

Type: defines which groups are affected.

X start:

X-End:

Y Start:

Y-End:

Properties sidebar(Mesh edit mode):

Vertex Weights

The Vertex Groups Panel in the properties sidebar (only in Edit mode) exposes the weight values for weight groups associated to the active vertex. These values can be modified. If multiple verts are selected, then you also can copy the weights of the active vertex to the selection (C Buttons at the right side).

• Normalize: Ensure that the sum of all displayed weights is 1.0
• Copy: Same as the “C” buttons but copies all weights in one step.

Mesh display

You can enable the display of weights in Edit mode. Then you can select the desired weight group from the vertex Group List in the Object Data properties. The weights from that group will be displayed on the surface of you edited mesh:

Note: When you change the weight values of a vertex, and when the related Weight map is selected for display, then you can see the changes of the weightmap instantly.

Object data Properties:

You find the Vertex groups list in the Object Data properties. Each deform bone can have one associated Vertex Group (with the same name as the bone). This vertex group contains the Weights associated to the bone.

Note: When you rename the vertex group, then you break the association to the bone.

In the example on the right you see 12 Deform groups are defined for 12 bones. You can select the active Deform group by clicking into the list.

You can lock each group to protect it from getting changed by any Weight group tool. You also can add (+) more Vertex groups for various other purposes, or remove existing groups (-).

At the bottom of the panel you find some more functions:

• Assign: Assigns the current set of selected vertices to the currently selected Vertex group. Note that for Assigning the currently selected vertices you can specify the exact weight value with the number slider at the bottom of this panel.
• Remove: Removes the current set of selected vertices from the currently selected Vertex group
• Select: Select all vertices in the Weight group (no vertex will be added to the weight group)
• Deselect: Deselect all vertices in the weight group (No vertex will be removed from the group)

When you click on the dark grey arrow down button (Below the +/- signs) then a Menu pops up containing all sorts of Weighting tools.

Hint: You can enlarge/shrink the list box size by holding down the SHIFT key and rolling the middle mouse roll button. You may need to move the mouse a bit as well while you roll the.

Modifiers

We also find some weight tools in the Modifier Stack. These Modifiers allow  to modify the weight maps in a non destructive way.

• Vertex Weight Edit
• Vertex Weight Mix
• Vertex weight Proximity

Menu (Weights)(weight Paint Mode)

• Weights -> assign from bone envelopes
• Weights -> Assign Automatic from bones