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To start working with terrain mesh, we must first have our topography selected. This is done by opening the Layout generation settings and activating the Topographic layout setting. We then click on Select - we must now select all of the topographical data in the drawing. Once we are sure all of our topographical data is selected, we press Space or Enter on the keyboard. We are now prepared to work with topographical data in PVcase.
In order to change the slope units this could be done by navigating to the Layout generation settings window and choosing from the drop-down menu percent or degrees.
Conventionally, the first step is to generate a terrain mesh prior to any PV frame design. This helps us assess the topography of the PV plant site, observe any surveyor data errors, and will make for easier identification of problematic regions in the PV area.
We start by clicking on the Terrain mesh icon, which will open the tool.
We start by defining the slope table parameters. We will set our start value as 0% and the end value as 14%. We are then able to specify the number of rows we want to have. This allows us to control the step size of our mesh. For our example, we will set it to 10 rows. For most cases, we advise 7 or more rows - this makes it easier to evaluate the terrain at a glance. We will click on Fill table - this will populate the table with indication ranges and the colors in which said ranges will be represented.
We are free to customize both the color of the range and the range values. The values can be double-clicked and modified as we see fit. To customize the colors of the ranges, we may click on the color we want to change and we are presented with a color-picking tool. Just select the color you want and click Confirm.
Having defined the slope table and coloring, our next step is to configure the Mesh settings.
The mesh density controls the distance between the centers of the triangular mesh components. Increasing the density makes for a more detailed mesh, but at the cost of computation time and an increased toll on performance. Lowering the density makes for a less insightful result, but creates one that takes less time to create and one that is generally less taxing on AutoCAD performance.
The density can be modified by moving the slider or by manually inputting the target mesh density value. Generally, we advise using a lower-density mesh initially - for example, 5 meters or more. In most cases, a terrain mesh with a density of 5 meters offers sufficient details for initial assessment, without severely impacting performance. This reduces the computation time and if there is a need for a finer mesh, it can be revisited and re-generated with a denser value.
The slope direction can be set to East-West, North-facing, South-facing or North-South.
East-West is generally used with fixed-tilt systems. North-South is generally used for Single-axis trackers and East-West systems. East-West & North-South systems evaluate the inclination in two orientations simultaneously. The individual North & South slope directions will only indicate the slope in that respective direction. For example, if we were to perform a North-facing mesh generation, the software will only indicate slopes that are in the north direction. This may be useful to consider when working with Single-Axis Tracker systems, as the Northern slope may influence the energy production capabilities.
For our example, we will utilize the North-South slope direction as our example will be used with a Single-axis Tracker system.
Once we have our parameters where we want them to be, we click on Generate Mesh, then select the PV area boundary line, and press Space or Enter on the keyboard. In a few moments the mesh will be generated.
The mesh is colored in a way that corresponds to the values in our slope table. We can better observe this by switching to a South-West Isometric view or by manually panning the viewing angle by holding Shift on the keyboard and the middle mouse button and moving the cursor.
The terrain mesh allows us to identify and locate regions with severe slopes in one or more directions. Depending on the severity of the slope and the needs of our system, we may choose to designate some areas as unsuitable terrain.
For our example, let us assume our project specification prevents us from placing frames in areas with slopes greater than 7 percent in a given direction. Once we have our mesh, we have the option to restrict areas based on the results of our terrain mesh generation. We right-click on the range that has the Minimum angle value at 7% and then we click on Draw restriction.
PVcase will draw polylines around areas that have a slope of more than 7% in either direction. If we click on the newly-drawn restriction line, we can see it is in the PVcase offsets layer. This means that when we generate our PV area, the software will not place any frames where these polylines were generated.
Export to CAD
We may also export the slope table and the information within it anywhere in our design area. This can be done by clicking on the Export to CAD button and placing the table on our workspace by left-clicking on the target location.
Exporting terrain mesh to PVsyst
The terrain mesh can be exported to PVSyst by selecting the option Export to PVsyst. On the action window in the drop-down menu, just select Terrain and frames, and PVcase will ask you to select the Terrain mesh. As a last step, select what format you want to save it in. (.DAE or . PVC) and click Export.
Two files will be generated, the first one with the extension .PVC or .DAE, and the second a .csv file:
Having the terrain in the CSV format rather than a 3D object file improves computation speed when running yield reports in PVSyst.