The editing of model grid through 2DH View is mainly done in the Layer Control window. The user first have to click on the pen icon 
to enable modifying, then RMC on the cells to directly edit or RMC on the layer to see additional options.
1. Model Grid Layer: RMC on Model Grid show options to modify the I and J indices of the model such as rotate, flip, transpose (Figure 1). These I-J functions are used during the grid generation- importing process to correct any model I-J orientation issues. Additionally, RMC on the model cell allow us to deactivate that cell or rotate grid cell corners for that cell (Figure 2). This function applies a rotation to the cell rotation angles, it does not rotate the actual cell. If using the CORNERS.INP file, it just applies a user specified rotation to the cell rotation matrix. In EFDC the cell’s rotation matrix is used for velocity plots and interaction with the wind field.
Figure 1. RMC on Model Grid layer to show I-J functions.
Figure 2. With Model Grid Layer selected, RMC on cell to edit.
On corner cells, the user have an added options of turning the border cell into an triangular cell (Figure 3) by RMC on the cell then select Change to Triangular Cells option. RMC on the cell again to show the option of changing it back to quad-cell by selecting option Change to Quadrangular Cells.
The use also can select multiple cells to apply this option at the same time by using Selection Tool first then use this feature as applying for a cell as described above. (See Figure 4).
To use this feature for all corner cells of a entire grid domain, from keyboard press Alt + T, an message form of Triangular cells on the border pop up as shown in Figure 5. Select Yes to convert all corner cells to triangular cells.
Figure 3. Triangular cell option in Model Grid layer (1).
Figure 4. Triangular cell option in Model Grid layer (2).
Figure 5. Triangular cell option in Model Grid layer (3).
2. Grid Connection Layer: Add N-S or E-W grid connectors for different grid domains. Select Grid Connections layer in Layer Control then RMC on a cell from one grid which is to be connected to another grid, and select Add N-S Connection (or Add E-W Connection), then LMC to set the second connection point (see Figure 6).
Figure 6. Add new grid connection.