== <cloud> ==

A cloud object represents a collection of mesh points over which a [wiki:rp_xml_ele_field <field>] is defined.

'''''Note: This format is deprecated. Use the <unstructured> subelement in the [wiki:rp_xml_ele_mesh <mesh>].'''''

[[image(zoo_2dcloud.gif)]]
{{{
<cloud id="m2d">
  <about>
    <label>2D Mesh</label>
  </about>
  <units>um</units>
  <hide>yes</hide>
  <points>0.125130060187 0.0609215651922
0.908746186136 0.297150382445
0.206477749723 0.271539598364
0.766029706582 0.661278515431
...
  </points>
</cloud>
<field id="f2d">
  <about>
    <label>2D Field</label>
  </about>
  <component>
    <mesh>output.cloud(m2d)</mesh>
    <values>0.0076231191192
0.270034276755
0.056066885231
0.506558987144
...
    </values>
  </component>
</field>
}}}
A cloud is nothing more than a shotgun blast of (x,y) points defining a mesh.  The actual mesh is computed from the points by Delaunay triangularization.  The <field> contains a <mesh> attribute with the name '''{{{output.cloud(m2d)}}}''', which points to our cloud as the underlying mesh.  Each value in the field corresponds to a point in the cloud.  The first value is for the first point in the cloud, the second for the second point, and so forth.

[[BR]]
[[rpimage(zoo_3dcloud.gif)]]
{{{
<cloud id="m3d">
  <about>
    <label>3D Mesh</label>
  </about>
  <units>um</units>
  <hide>yes</hide>
  <points>0.492078342704 0.360705828462 0.38285896293
0.710589967999 0.885592158365 0.147405638428
0.44656506155 0.418989469492 0.956013757715
0.723225916141 0.257972586554 0.745262220849
...
  </points>
</cloud>

<field id="f3d">
  <about>
    <label>3D Field</label>
  </about>
  <component>
    <mesh>output.cloud(m3d)</mesh>
    <values>0.0679557531138
0.0927613221947
0.178875965822
0.139045406075
0.0162795817362
    </values>
  </component>
</field>
}}}

A cloud can also be defined with (x,y,z) points, which are triangularized into a tetrahedra to form a 3D mesh.  But other than that, the example is the same.  The <field> contains a <mesh> that points to the '''{{{output.cloud(m3d)}}}''' mesh, and then defines values for each point in the mesh.

You can see working code in the [browser:trunk/examples/zoo zoo of examples] in the [browser:trunk/examples/zoo/cloud cloud example] or on the hub in the directory /apps/rappture/examples/zoo/cloud.