Optimizing Surfaces

Surfaces can be optimized to reduce the time required to compute them and reduce the memory required to store them. The biggest result of optimizing surfaces is faster drawing speeds.

As a general rule, TPC triangulates 10,000 points per seconds. Even faster triangulation times can be achieved by turning off breaklines and removing the optional border traverse.

Large surfaces can cause a drawing to respond more slowly to the mouse as you edit a drawing. This is a direct result of the ‘hit-test’ regions created for each contour or TIN line displayed in the drawing. You can greatly increase drawing speed by ignoring surface objects like minor contour line and TIN lines.

• Right click any minor contour line and choose Layer Tools, Modify Layer, Ignore. The cursor will no longer react to any minor contour line even though they are still displayed in the drawing. You will still be able to edit the contours by selecting any major contour line.
• For even greater speed, don't draw the minor contours until you plot the drawing.

The Advanded tab of the Surface Settings inlcudes a Manual Recompute toggle. This setting determines when TPC recomputes the TIN for the surface.

Turn this toggle Off while you interactively edit the surface if you want the surface to immediatly reflect the change you are making. Surface edits along with the Regnerate command in Drawing View will force the surface to be re-triangulated.

Turn this toggle On once you have the surface looking the way you want it. From then on, the Regenerate command in the Drawing View will NOT recompute the surface. To recompute the surface you will need to manually recompute the surface.

Once the contour lines are drawn, the points, triangles and edges used to create them can be discarded to free up system memory on your computer. There are both advantages and disadvantages to retaining (default) these objects.

• To discard the TIN objects, turn on Minimize Memory Requirements in the Advanded tab of the Surface Settings dialog.

When you minimize the memory requirements, you will notice the following limitations.

• When you choose the Surface Info command, TPC includes a message telling you it cannot report any potential problems with memory minimizes. You will still get the basic information on number of points, triangles, edges, breaklines and computation time. You will need to turn this option off to report things like unresolved edges, breaklines and duplicate topo points.
• When computing the volume to another surface for which memory has been minimized, TPC must compute the TIN for that surface before it computes the volume. This is a minor inconvenience that will typically add less than a second to the volume computations.
• When you position the cursor over a TIN line (you must have turned TIN lines on in the Surface Settings) TPC can not display the end points of the TIN line in the status line.

As a general rule, leave this option to minimize memory OFF while you are editing your surface then turn it ON once you are finished editing the surface.