**********
Properties
**********

.. admonition:: Reference
   :class: refbox

   :Mode:      Object or Edit Modes
   :Panel:     :menuselection:`Properties editor --> Metaball`

All Meta objects in a scene interact with each other.
The settings in the *Metaball* section apply to all meta objects.
In *Edit Mode*,
the *Active Element* panel appears for editing individual meta elements.

.. list-table::

   * - .. figure:: /images/modeling_metas_properties_metaball-panel.png

          global meta properties.

     - .. figure:: /images/modeling_metas_properties_active-element-panel.png

          individual meta properties.


Resolution
==========

The *Resolution* controls the resolution of the resultant mesh as generated by the Meta object.

View
   The 3D View resolution of the generated mesh. The range is from (0.05 to 1.0) (finest to coarsest).
Render
   The rendered resolution of the generated mesh. The range is from (0.05 to 1.0) (finest to coarsest).

One way to see the underlying mathematical structure is to lower the *Resolution*,
increase the *Threshold* and set the *Stiffness* (see below)
a fraction above the *Threshold*. Fig. :ref:`fig-meta-intro-underlying` is a *Meta cube*
with the above mentioned configuration applied as follows:
*Resolution* of 0.410, *Threshold* of 5.0 and *Stiffness* a fraction above at 5.01.

.. list-table::


   * - .. _fig-meta-intro-underlying:

       .. figure:: /images/modeling_metas_properties_underlying-structure.png

          Underlying structure.

     - .. figure:: /images/modeling_metas_properties_underlying-structure-shape.png

          Meta cube shape.

You can clearly see the underlying cubic structure that gives the meta cube its shape.


Threshold (Influence)
=====================

*Threshold* defines how much a meta's surface "influences" other metas.
It controls the *field level* at which the surface is computed.
The setting is global to a group of *Meta* objects.
As the threshold increases, the influence that each meta has on each other increases.

There are two types of influence: *positive* or *negative*. The type can be toggled on
the *Active Element* panel while in *Edit Mode*,
using the *Negative* button.
You could think of *positive* as attraction and *negative* as repulsion of meshes.
A negative meta will push away or repel the meshes of positive *Meta* objects.

.. _fig-meta-intro-positive:

.. figure:: /images/modeling_metas_editing_family.png
   :width: 450px

   Positive influence of three meta balls.

A *positive* influence is defined as an attraction,
meaning the meshes will stretch towards each other as the *rings of influence* intersect.
Fig. :ref:`fig-meta-intro-positive` shows three meta balls' *rings of influence*
intersecting with a *positive* influence.

Notice how the meshes have pulled towards one another.
The area circled in white shows the green *influence* rings intersecting.


Update
======

While transforming metas (grab/move, scale, etc.), you have four "modes" of visualization,
located in the *Update* buttons group of the *Metaball* panel:

Always
   fully draw the meta during transformations.
Half
   During transformations, draw the meta at half its *Wiresize* resolution.
Fast
   Do not show meta mesh during transformations.
Never
   Never show meta mesh (not a very recommended option, as the meta is only visible at render time!).

This should help you if you experience difficulties (metas are quite computationally intensive...),
but with modern computers, this should not happen, unless you use many metas,
or very high resolutions...