Boundary Fitted Grid Tools

The main portion of a boundary fitted finite difference grid for use with CH3D is created using the CH3D Coverage inside the Map Module. This allows the grid to be constructed and reconstructed on a conceptual basis before determining the final grid detail. In addition to the CH3D coverage, certain tools allow manual manipulation of the grid or are required to define boundary conditions.

These tools are contained in the Dynamic Tools portion of the tool palette when the Boundary Fitted Finite Difference Grid Module is active.

Select Grid Nodes

The Select Grid Nodes tool selects a group of grid nodes by dragging a box around them. Multiple groups of nodes may be selected by holding the SHIFT key and dragging multiple boxes in the graphics window. The main use of selecting nodes in the grid module is for deletion. However, if exactly two nodes are selected, the Help Window shows the exact distance between them. New nodes can also be interpolated between two selected nodes using the Interpolation Options and Interpolation items from the Nodes menu. For node centered grids, the new node is assigned a bathymetry value according to the options set in the node options dialog.

Create Grid Nodes

The Create Grid Nodes tool is used to manually create individual grid nodes. A node will be created at the mouse cursor location. If the new node is inside an existing grid cell, and the insert nodes into grid option is turned on, then the cell is split, as well as all other cells in the row and column of the cell.

Create Grid Cells

The Create Grid Cells tool is used to manually create an individual cell by selecting four nodes, either individually or by dragging a box around them. The new cell is assigned the default material type that is set in the cell options dialog. For cell centered grids, the new cell is also assigned a bathymetry value according to the values in the Cell Options dialog.

Create Grid Nodestrings

The Create Grid Nodestrings tool is used to define a set of nodes along a line. The only use of nodestrings in the grid module is for creating a Patch. To create a nodestring, you should single-click each of the nodes to be included, then double-click the last node to end the nodestring. To create a nodestring across a set of nodes that are attached to elements, click the first node then hold the SHIFT key as you click the last node and SMS will automatically include all nodes between the two. As long as the nodestring has not been finished with a double-click, you can backup one node by pressing the Backspace key on your keyboard.

Select Grid Nodestrings

The Select Grid Nodestrings tool is used to select nodestrings that have already been created. When this tool is selected, a small icon appears at the center of each nodestring. To select a nodestring, click inside this icon. Multiple nodestrings may be selected simultaneously by either dragging a box around a set of icons or holding the SHIFT key and clicking inside multiple icons.

Create Grid Cellstrings

The Create Grid Cellstrings tool is used to define a cellstring across a set of cells. Cellstrings are required to define boundary conditions in the grid module. Create a cellstring by clicking on the symbol at the center of the first cell and then double-clicking on the symbol at the center of the last cell. When creating cellstrings, you do not need to hold the SHIFT key to automatically select all nodes between the first and last clicked cells because this done automatically. However, you may hold the CTRL key to only add the cells that you click into the cellstring.

Select Grid Cellstrings

The Select Grid Cellstrings tool is used to select cellstrings that have already been created. When this tool is selected, a small icon appears at the center of each cellstring. To select a cellstring, click inside this icon. Multiple cellstrings may be selected simultaneously by either dragging a box around a set of icons or holding the SHIFT key and clicking inside multiple icons. After selecting a cellstring, the boundary conditions can be assigned.

Select Grid Cells

The Select Grid Cells tool is used to select individual or groups of cells. An individual cell is selected simply by clicking on it. To select an additional cell, hold the SHIFT key as you click on another cell. Groups of cells may be selected by dragging a box around them. In addition, a line of cells may be selected by holding the CTRL key and dragging a line through the desired cells. Both the selection box and the drag line selection types work with the SHIFT key.

Select Grid Columns

The Select Grid Columns tool is used to select an entire column of cells by clicking inside one of the cells in the column. Cells that are disjoint from the clicked cell will not be selected. If the grid orientation is rotated, the "column" may appear to be a row, but it is always a column in the parametric grid space.

Select Grid Rows

The Select Grid Rows tool is used to select an entire row of cells by clicking inside one of the cells in the row. Cells that are disjoint from the clicked cell will not be selected. If the grid orientation is rotated, the "row" may appear to be a column, but it is always a row in the parametric grid space.

Drag Grid Column and Grid Row

The Slide Grid Cells tool is used to drag the line between two rows or columns of grid cells. This tool is not fully operative as of this writing.

Split Grid Column and Row

The Split Grid Cells tool is used to split a single row or column into two. When you click on the edge between two cells, the entire row/column splits at the mouse cursor point. This is useful to quickly refine around a small area.

Label Contours

The Label Contours tool is used to manually place a contour lable at the mouse cursor point. There are also available automatic contour label options.