April, 2001 Version 2.01

Please read the documentation for the previous version of R2Dmesh in addition to this readme file. Notes in this readme are based on the user knowing the functions of the previous version.

The April 2001 version of R2D mesh was translated from Borland to Microsoft C++ for consistency with the other programs in the River2D family. The following enhancements have been added:

Command Icons similar to R2D_Bed, expanded point and line editing capabilities, and color plotting of underlying bed. Individual tools are bulleted below:

Display:
1. Right click to get a menu of display options. Display of most bed and mesh features can be selectively toggled on and off.
2. A color plot of bed allows easier visualization of relative elevation of bathymetric features. Toggling color on and off while developing mesh breaklines is especially useful.

Node editing:
1. You can now add/delete fixed as well as floating nodes. There are toolbar icons for those operations.
2. Drag and drop of mesh nodes is allowed. This allows you to slide a floating or fixed node or breakline fixed node that last little bit to get right where you want it. (Sure beats redrawing the breakline!) The drag icon shows a node with an arrow dragging it.
3. Boundary nodes may be deleted. If you find the boundary ought to be somewhere else, you can drag boundary nodes where you want them and/or delete extraneous boundary nodes. For example, at lower flows you don't need all that flood plain in the mesh. If you drag the boundary within the existing mesh, all mesh elements outside of the new boundary will be discarded.

Line editing:
1. You can delete breakline segments. When deleting a breakline segment, the sliding nodes on either end of the segment become fixed nodes that terminate the breakline. If you delete several breakline segments, you have several fixed nodes left (That can also be deleted.)
2. Fixed nodes on breaklines can be "Dragged and Dropped", but ONLY if there are no adjacent sliding nodes. This feature is most useful for exact placement of a breakline prior to triangulation. Place the breakline in the approximate location while zoomed out, then zoom in and drag the nodes where you want them, then triangulate.
3. When drawing breaklines, there are now icons for both Snap to Mesh Breakpoint and Snap to Bed Breakpoint. It is most useful to turn them on and off at the immediate time they are needed as the snapping algorithm and the skill of at least my use occasionally snaps to an unexpected location. Fortunately, with the breakline editing features of the program, such an errant breakline can now be easily removed.

Boundary editing:
1. In addition to deleting boundary nodes as noted above, you can bisect a specific boundary segment (see the hatchet toolbar icon) with a new fixed node. This is especially useful to subdivide a localized portion of the boundary without smoothing. Late in the mesh building process, smoothing may move floating or sliding nodes that you have found to be in very good locations.
2. As with breaklines, the sliding nodes on a boundary segment must be deleted before a fixed boundary node can be "dragged".

Finding the "bad" triangle:
1. The triangle with the poorest aspect ratio can be quickly located by clicking the red triangle icon. The program will zoom one magnification and center on that triangle. If the triangle is too small to see, just click the icon again until the zoom is sufficient to see the triangle.

Terry J. Waddle, Ph.D.
Hydrologist
U.S. Geological Survey
4512 McMurry Ave.
Ft. Collins, CO 80525-3400
U. S. A.

September 30, 2002 Version 2.02

1. Added a memory device context, which eliminates screen flicker when screen in updated.
2. Bug fix - random lines or random colour fill no longer appear after zooming in repeatly (when displaying the triangulation or colour map).
3. Mapped function keys F2 and F3 to "Zoom in on Rectangle" and "Zoom Out" respectively.
4. Added new program icons.
5. Added new command that allows the user to import Ice Topography files so that 'ice features' can be incorporated into the computational mesh.
6. Added ability to display ice thickness using a colour map (found in the Display Options dialog).
7. Added new and improved (faster) triangulation routine.