doc/salome/gui/SMESH/files/constructing_meshes.htm

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 103 <h1>Constructing meshes</h1>
 104
 105 <p class="whs1">Construction of a mesh consists of:</p>
 106
 107 <p class="whs1">&nbsp;</p>
 108
 109 <ul type="disc" class="whs2">
 110
 111         <li class=kadov-p><p class="whs1">Selecting a geometrical
 112  object for meshing</p></li>
 113
 114         <li class=kadov-p><p class="whs1">Applying <a href="about_meshing_algorithms.htm">meshing
 115  algorithms</a> and <a href="about_hypotheses.htm">hypotheses</a> which
 116  will be used at computation of this mesh.</p></li>
 117 </ul>
 118
 119 <p class="whs1">&nbsp;</p>
 120
 121 <p class=TODO>To construct a mesh:</p>
 122
 123 <p class="whs3">1. In the <span style="font-weight: bold;"><B>Mesh
 124  </B></span>menu select<span style="font-weight: bold;"><B> Create Mesh </B></span>or
 125  click <img src="../image32.gif" width="22px" height="24px" border="0" class="img_whs4"> button in the toolbar. The following dialog box will
 126  appear:</p>
 127
 128 <p class="whs3">&nbsp;</p>
 129
 130 <p class="whs5"><img src="../pics/createmesh-inv.png" x-maintain-ratio="TRUE" width="370px" height="296px" border="0" class="img_whs6"></p>
 131
 132 <p class="whs5">&nbsp;</p>
 133
 134 <p class="whs3">2. For example, you need to mesh a 3d object.
 135  </p>
 136
 137 <p class="whs3">First, type the name for your mesh in the
 138  &quot;Name&quot; box, by default, it is &quot;Mesh_1&quot;. Then select
 139  the object you wish to mesh in the Object Browser <img src="../image119.gif" width="173px" height="88px" border="0" class="img_whs7">and click
 140  the <img src="../image120.gif" width="34px" height="29px" border="0" class="img_whs8"> &quot;Add&quot; button. </p>
 141
 142 <p class="whs3">Now you can define 1d Algorithm and 1d Hypotheses,
 143  which will be applied to the edges of your object. (Note that any object
 144  has edges, even if their existence is not apparent, for example, a sphere
 145  has 4 edges). Click the &nbsp;<img src="../image121.gif" width="29px" height="28px" border="0" class="img_whs9"> button to add a hypothesis. Click the <img src="../image122.gif" width="30px" height="29px" border="0" class="img_whs10"> button
 146  to define values for the current hypothesis. The use of additional hypotheses
 147  is optional (i.e. you may leave &quot;None&quot; in this box). &nbsp;&nbsp;</p>
 148
 149 <p class="whs3">&nbsp;</p>
 150
 151 <p class="whs3">Proceed in the same way with 2d and 3d Algorithms
 152  and Hypotheses, note that the choice of hypotheses depends on the algorithm.
 153  There must be one Algorithm and one or several Hypotheses for each dimension
 154  of your object, otherwise you will not get any mesh at all. Of course,
 155  if you wish to mesh a face, which is a 2d object, you don't need to define
 156  3d Algorithm and Hypotheses. </p>
 157
 158 <p class="whs3">In the <span style="font-weight: bold;"><B>Object
 159  Browser</B></span> the structure of the new mesh will be displayed as follows:</p>
 160
 161 <p class="whs3"><img src="../image88.jpg" width="232px" height="142px" align="right" border="0" class="img_whs11">It contains:</p>
 162
 163 <ul type="disc" class="whs2">
 164
 165         <li class=kadov-p><p class="whs3">a reference to the
 166  geometrical object on the basis of which the mesh has been constructed;</p></li>
 167
 168         <li class=kadov-p><p class="whs3"><span style="font-weight: bold;"><B>Applied
 169  hypotheses </B></span>folder containing the references to the hypotheses applied
 170  to the construction of the mesh;</p></li>
 171
 172         <li class=kadov-p><p class="whs3"><span style="font-weight: bold;"><B>Applied
 173  algorithms </B></span>folder containing the references to the algorithms applied
 174  to the construction of the mesh.</p></li>
 175 </ul>
 176
 177 <p class="whs3">&nbsp;</p>
 178
 179 <p class="whs3">There is an alternative way to create a mesh
 180  on an object simply by clicking <span style="font-weight: bold;"><B>Assign
 181  a set of hypotheses </B></span>button and selecting between Automatic Tetrahedralization
 182  or Hexahedralization. &nbsp;The
 183  program will automatically generate a 3D mesh with the most appropriate
 184  settings. In the same way you can apply this functionality for meshing
 185  2D objects, in which case 3D algorithms are not applied. </p>
 186
 187 <p class="whs3">&nbsp;</p>
 188
 189 <p class="whs3">3. Now, when everything is ready, select
 190  your mesh in the <span style="font-weight: bold;"><B>Object Browser</B></span>.
 191  &nbsp;From the
 192  <span style="font-weight: bold;"><B>Mesh </B></span>menu select<span style="font-weight: bold;"><B>
 193  Compute </B></span>or click <img src="../image28.gif" width="25px" height="24px" border="0" class="img_whs12"> button of the toolbar. The Mesh
 194  Computation information box appears.</p>
 195
 196 <p class="whs3">&nbsp;</p>
 197
 198 <p class="whs3"><img src="../pics/meshcomputationsucceed.png" x-maintain-ratio="TRUE" width="457px" height="486px" border="0" class="img_whs13"></p>
 199
 200 <p class="whs3">&nbsp;</p>
 201
 202 <p class="whs3">If the mesh computation failed, the information
 203  about the cause of the failure is provided. </p>
 204
 205 <p class="whs3">&nbsp;</p>
 206
 207 <p class="whs3"><img src="../pics/meshcomputationfail.png" x-maintain-ratio="TRUE" width="564px" height="402px" border="0" class="img_whs14"> </p>
 208
 209 <p class="whs3">&nbsp;</p>
 210
 211 <p class="whs3">After you select the error, <span style="font-weight: bold;"><B>Show
 212  Subshape</B></span> button allows visualizing the mesh elements that cause
 213  it</p>
 214
 215 <p class="whs3">&nbsp;</p>
 216
 217 <p class="whs3"><img src="../pics/failed_computation.png" x-maintain-ratio="TRUE" width="260px" height="270px" border="0" class="img_whs15"> </p>
 218
 219 <p class="whs3">&nbsp;</p>
 220
 221 <p class="whs3"><span style="font-weight: bold;"><B>Publish
 222  Subshape</B></span> button allows importing it in a separate MED or UNV file.
 223  </p>
 224
 225 <p class="whs3">&nbsp;</p>
 226
 227 <p class="whs3">Consider trying a sample script for construction
 228  of a mesh from our <a href="../constructing_meshes.htm">TUI Scripts</a>
 229  section.</p>
 230
 231 <p class="whs3">&nbsp;</p>
 232
 233 <p>&nbsp;</p>
 234
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