SurfaceModeller

This parameter allows groups to be formed by attribute values. Zero or more attributes may be specified.

Input features with the same attribute values are placed into the same group. The transformer then operates independently on each group of input features.

If this parameter is left blank, the transformer will treat the entire set of input features as one group.

How parallel processing works with FME: see About Parallel Processing for detailed information.

This parameter determines whether or not the transformer should perform the work across parallel processes. If it is enabled, a process will be launched for each group specified by the Group By parameter.

Parallel Processing Levels

Parameter	Number of Processes
No Parallelism	1
Minimal	coresThe processor, or CPU, is the physical part of the computer that performs mathematical calculations. It is the most important part of a computer system. Traditional processors have only one core on the processor, meaning that at any given time, only one set of calculations is being performed. If a processor is dual-core, this means the single chip contains hardware for two processors, now called cores to distinguish them from the single chip, running simultaneously, side by side. (Source: http://www.ehow.com/facts_5730257_computer-core-processors_.html) / 2
Moderate	exact number of cores
Aggressive	cores x 1.5
Extreme	cores x 2

For example, on a quad-core machine, minimal parallelism will result in two simultaneous FME processes. Extreme parallelism on an 8-core machine would result in 16 simultaneous processes.

You can experiment with this feature and view the information in the Windows Task Manager and the Workbench Log window.

This parameter is used to determine which input points to add to the surface model as vertices. Specifying a value of 0 turns off vertex filtering.

Tip: A larger value will speed up surface model construction. The larger the value, the more input points will be filtered out. For input files with millions – or even billions – of points, it becomes essential to increase this value.

When a positive value for surface tolerance is specified, it works as follows. For each vertex that is being added to the model:

• If the x,y location is outside the 2D convex hull of the existing surface model, it is added to the model.
• If the x,y location is inside the 2D convex hull of the existing surface model:
  • The difference between the z value from the existing surface model and the z value of the vertex is calculated.
  • This difference is compared to the surface model tolerance.
  • The vertex is only added to the surface model if the difference is greater than the surface tolerance; otherwise, the vertex is discarded.

This parameter controls whether input DRAPE_FEATURES will retain its vertex count, or be modified to adhere to the underlying surface model:

• If Drape Method is set to VERTEX, the input feature will be output with the same number of vertices, with z values set on each vertex. The z values are interpolated from the underlying surface model.
• If Drape Method is set to MODEL, the feature will have other vertices added to more closely follow the underlying surface model. For example, if an input DRAPE_FEATURE falls outside the underlying surface model, it will gain additional vertices where the DRAPE_FEATURE crosses the boundaries of the surface model.

This parameter is used for the output ports DEM_POINTS and DEM_RASTER when these output ports exist on the transformer. It is also used if DRAPE_FEATURES are input to the model.

• AUTO: The transformer will calculate each output point automatically. The PLANAR method is used if the output point is within a surface triangle in xy and the CONSTANT method is used otherwise.
• PLANAR: Barycentric interpolation is used to determine the z value for each output point. If an output point is outside the 2D convex hull of the surface model, the output z value will be set to NaN.
• CONSTANT: The z value of each output point is set to the z value of the closest vertex in the underlying model.

This parameter specifies the name of an elevation attribute for the output ports CONTOURS and DEM_POINTS, when these output ports exist on the transformer.

This parameter specifies the elevation separation of the output contours.

This parameter specifies whether the output contours are 2D or 3D. 2D contours are equivalent to 3D contours, except that the z coordinates are dropped.

Tip: When the input dataset is large enough, setting this parameter to 2D will result in a visible performance improvement.

This parameter controls whether input points on the contour interval are dropped, or perturbed. Not dropping or perturbing these points would result in topologically invalid contours.

• Perturb Input Points on Contour Interval: Contours are negatively offset in the z direction. The perturbation amount is 1% of the contour interval.
• Remove Input Points on Contour Interval: Input points on the contour interval are not added to the underlying surface model.

These parameters specify the x and y sampling intervals for the output DEM_POINTS.

This parameter is used only when Interpolation Method is set to PLANAR, and it only affects the output port DEM_RASTER.

All output raster cells that fall outside the underlying surface model’s boundaries will be assigned the value of this parameter.

When this parameter is blank, it is interpreted as NaN.

Note: To ensure consistent raster output, it is highly recommended that you do not leave this parameter blank.

This parameter allows you to define a file for storing a surface model.

File storage is useful for building a large surface model through multiple runs, and for workspaces that need to re-use a preconstructed surface model. The saved surface models can be used as part of a production stream on the same operating system.

Note: This parameter is processed only if Group By is not specified.

This parameter specifies the filename, including its path, of the surface model file. The surface model file has the file extension *.fsm.

This parameter controls whether the workspace is reading or writing a surface model file.

Note: There must be at least one input feature. For reading, it suffices to input a null feature via any of the input ports.

• Read or Append: Reads the surface model from the specified file, and appends it to the surface model constructed by the input features. The appended model is then written back to the same file.
• Write or Overwrite: Writes the constructed surface model to the specified file. If the specified file exists, it will be overwritten.

This parameter provides an estimate of the number of vertices in the final surface model, which can be significantly greater than the total number of input points through POINTS/LINES and BREAKLINES.

Note: A generous estimate is recommended when you are building a large model in multiple runs because this estimate is used for optimization purposes. If this estimate is too low, the surface model construction could take significantly longer.

This parameter should only be used when you are building large surface models across multiple runs.

Note: In subsequent runs of the SurfaceModeller, this parameter must be specified or else the transformer will use the bounding box of the surface model from the first run for constructing the surface model.