SMS:2D Mesh Node Options Dialog

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The Mesh Module Node Options dialog

Parameters governing the creation and manipulation of nodes are set using the Node Options dialog, which is opened by selecting the menu Nodes | Options.

Individual Node Options

  • Insert nodes into triangulated mesh – When a node is created inside the mesh boundary with the Create Mesh Nodes tool, it can become part of the mesh. If this option is turned off, new nodes are not added to the mesh triangulation and remain disjoint. This option also applies to nodes created using the Interpolate command from the Nodes menu.
  • Retriangulate voids when deleting – See below.
  • Node Z value – The z-value of a node created with the Create Mesh Nodes tool is based on the chosen option:
    • Interpolate z-value from mesh – The Z coordinate is determined by interpolation from the existing mesh. If this option is turned off or the node is created outside the existing mesh boundary, the default Z coordinate is assigned.
    • Assign default z-value – The Z coordinate is assigned the default value.
    • Prompt for z-value – A dialog will prompt for the Z coordinate of each node after it is created.
    • Interpolate z-value from active scatter – The Z coordinate is determined by interpolation from the active scatter set. If the node is created outside the active scatter set boundary, the default Z coordinate is assigned.

Retriangulate Voids When Deleting

When deleting a node is deleted, all elements attached to the node are also deleted. The void in the mesh left by the deleted elements can be automatically filled by triangulating the surrounding nodes. If this option is turned off, then the void will remain.

If the Retriangulate voids when deleting option is turned on, the void created when a node and the elements surrounding the node are deleted is re-triangulated or filled in with triangles. This feature makes it possible to selectively "unrefine" a region of the mesh or reduce the density of the nodes in a region of the mesh without having to completely recreate all of the elements in the region.

When deleting selected mesh nodes, if the node count exceeds ~1000 there will be a noticeable delay if the Retriagulate voids when deleting box is checked.

Duplicate Node Options

  • Merge adjacent elements when deleting – When a duplicate node is removed, the adjacent mesh elements are merged.
  • Tolerance – Two nodes closer than this tolerance value will be considered identical for selection and deletion of one of them. Also used by the automated mesh generation algorithms of SMS as a minimum node spacing. The tolerance should be specified in feet or meters. If using a Geographic Coordinate System, the tolerance is automatically converted by SMS to meters.
  • Select/Delete duplicate nodes – The Nodes | Select/Delete Duplicate Nodes command is based on this selection.

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