This section describes the data format for importing surface data Z(x,y) into the import primitive. It provides example data files and example script files that generate the data files. This object is sometimes used to import atomic force microscope (AFM) data.
File formats
The file formats are shown in the following tables. Spaces, commas or tabs can be used as separators in the files. The columns do not have to be aligned. Please note that as shown below, the data ranges go from 0 to m for x (0 to n for y). This means that there are actually m+1 data points in x and n+1 data points in y.
Z = Z(x,y): It is often easy to reverse the meaning of x and y when exporting a file. The surface import window provides a check button to invert x and y to correct this problem easily.
| Description | File format |
|---|---|
|
type 1: The x and y data is contained in the file. An example file is usr_surface_3d_1.txt. A script file that generates this example is usr_surface_3d_1.lsf. |
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type 2: The x and y data is not contained in the file. An example file is usr_surface_3d_2.txt. A script file that generates this example is usr_surface_3d_2.lsf. |
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Surface object import
Using GUI
To import surface data, click on the Surface option 
of the Import button in the main toolbar, which will open the Surface data import wizard.
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- SELECT FILE: let the user specify the data file to be imported.
- X, Y, Z: the data origin in the global coordinates of the Graphical Layout Editor. For example, if you are importing a surface defined by an AFM that is on a slab of Si that ranges from 0 to 2 microns, you should set z0 to 2 microns.
- X SPAN, Y SPAN: This defines the size of surface area that you are importing. If the x and y data was contained in the file (file format type 1), then these fields are inactive. If the x and y data was not in the file, then these fields are active and should be set to the desired data span.`
- UPPER SURFACE, LOWER SURFACE: Choose which surface is being imported.
- FILE UNITS: Select units for the data in your file.
- INVERT X AND Y AXIS: It is often easy to invert the x and y axis when exporting the file. Selecting this checkbox means that the x and y axes are automatically reversed.
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Note: importing surfaces for 2D simulations or other orientations (eg. X(y,z) or Y(x,z)) The import object always creates a surface as a function of x,y. If you need the a different surface orientation (such as when running 2D simulations which are oriented in the XY plane), use the object rotation property to rotate the object into a different plane. |
After surface data has been imported, the Import data tab allows the following properties to be modified:
- IMPORT: You can import new data into the object, or clear the imported data via a simple GUI. For properties of the import GUI, see bottom of page.
- X,Y FINE SCALE ADJUSTMENTS: Re-scale the object X,Y span. Modifying these properties will change the X,Y span properties. Z SCALE property not used for surface import.
- DATA SIZE: These properties provide some information about the imported data. They are read-only.
- LOWER, UPPER REF HEIGHT: Set the vertical location of the reference plane (height=0 in the imported data). Modifying these properties will change the Z, Z span properties.
Using Script
The following script commands are described in detail in the Scripting chapter. Examples script files are provided here.
|
Command |
Example files |
Description |
|---|---|---|
|
importsurface |
usr_surface_3d_1.txt usr_surface_3d_1.lsf |
Import surface data from a file created by usr_surface_3d_1.lsf |
|
importsurface2 |
usr_surface_3d_2.txt usr_surface_3d_2.lsf |
Import surface data from script variables |
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Note: Related properties It is important to notice that the 'x, y scale' and 'x, y span' properties are linearly related. Doubling the object 'x span' will automatically double the 'x scale' property. Similarly, the 'lower, upper ref height' properties are related to the 'z and z span' properties, although the relationship is slightly more complex. See the following figure for details. The surface's can be truncated by setting the 'z span' property to a small value. |
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Note: Overlapping surfaces If the z span is small enough such that the upper and lower surfaces overlap (as shown below), no structure will be included in the simulation in that region. |
