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| | align = "center" | [[Image:Tool_ContourLabels.GIF]] || Contour Labels || The Contour Label tool is used to manually place numerical contour elevation labels at points clicked on with the mouse. These labels remain on the screen until the contour options are changed, until they are deleted using the Contour Labels dialog, or until the mesh is edited in any way. Contour labels can be deleted with this tool by holding down the '''Shift''' key while clicking on the labels. This tool may only be used when the 2D mesh is in plan view. | | | align = "center" | [[Image:Tool_ContourLabels.GIF]] || Contour Labels || The Contour Label tool is used to manually place numerical contour elevation labels at points clicked on with the mouse. These labels remain on the screen until the contour options are changed, until they are deleted using the Contour Labels dialog, or until the mesh is edited in any way. Contour labels can be deleted with this tool by holding down the '''Shift''' key while clicking on the labels. This tool may only be used when the 2D mesh is in plan view. |
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| | align = "center" | [[Image:Tool_CreateLinTriElement.GIF]] || Create Linear Triangle Element || rowspan = "4" | Four types of elements are supported by the 2D Mesh module:
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| #[[Image:Tool_CreateLinTriElement.GIF]] Three node triangles (linear triangles).
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| #[[Image:Tool_CreateQuadLinElement.GIF]] Six node triangles (quadratic triangles).
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| #[[Image:Tool_CreateLinQuadElement.GIF]] Four node quadrilaterals (linear quadrilaterals).
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| #[[Image:Tool_CreateQuadQuadElement.GIF]] Eight node quadrilaterals (quadratic quadrilaterals).
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| Elements can be created using automatic meshing techniques such as triangulation. However, it is often necessary to edit a mesh by creating elements one at a time using the four Create Element tools.
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| A single element can be constructed from a set of existing nodes using the following steps:
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| #Select the tool corresponding to the type of element to be created.
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| #Select the nodes corresponding to the corner nodes of the element in consecutive order around the perimeter of the element. The nodes can be selected in either clockwise or counter-clockwise order. It is also possible to build an element by dragging a rectangle to enclose the nodes making up the new element rather than selecting each node one by one. A beep will sound if the wrong number of nodes for the current element type are selected.
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| If the current element type is a quadratic element (six or eight node element), the midside nodes of the element are created automatically. If the new element is adjacent to an existing element, the midside node of the existing element is used for the new element and a new midside node is not created, i.e., midside nodes are not duplicated.The coordinates of midside nodes cannot be edited. Midside nodes are always assumed to be located at the midpoint of the two adjacent corner nodes. When a corner node is edited, the coordinates of the adjacent midside nodes are updated accordingly.
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| :[[Image:Nodes1.gif]]
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| GMS performs several checks when a new element is constructed. The new element is checked to see whether or not it is ill-formed (the element has a twist in it or is self intersecting). The element is also checked to see if it overlaps any of the elements adjacent to the nodes comprising the new element. In addition, the elements adjacent to a new element are checked to ensure that the elements are conforming, i.e., linear elements (three and four node elements) are not allowed to be placed adjacent to quadratic elements (six and eight node elements). If any of the above checks fail, the construction of the new element is aborted.
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| | align = "center" | [[Image:Tool_CreateQuadLinElement.GIF]] || Create Quadratic Triangle Element
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| | align = "center" | [[Image:Tool_CreateLinQuadElement.GIF]] || Create Linear Quadrilateral Element
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| | align = "center" | [[Image:Tool_CreateQuadQuadElement.GIF]] || Create Quadratic Quadrilateral Element
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| |} | | |} |
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