AppearanceMerger

Features that contain some geometry on which an appearance may be set.

The appearance to be used as the source is taken from the first feature from each group sent into this port.

All input Requestor features are output whether or not anything was changed.

Note that only the first Supplier feature will be used in each "Group By" group.

Note: 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

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.

No: This is the default behavior. Processing will only occur in this transformer once all input is present.

By Group: This transformer will process input groups in order. Changes of the value of the Group By parameter on the input stream will trigger batch processing on the currently accumulating group. This will improve overall speed if groups are large/complex, but could cause undesired behavior if input groups are not truly ordered.

Considerations for Using Input is Ordered By

Using Ordered input can provide performance gains in some scenarios, however, it is not always preferable, or even possible. Consider the following when using it, with both one- and two-input transformers.

Single Datasets/Feature Types: Are generally the optimal candidates for Ordered processing. If you know that the dataset is correctly ordered by the Group By attribute, using Input is Ordered By can improve performance, depending on the size and complexity of the data.

If the input is coming from a database, using ORDER BY in a SQL statement to have the database pre-order the data can be an extremely effective way to improve performance. Consider using a Database Readers with a SQL statement, or the SQLCreator transformer.

Multiple Datasets/Feature Types: Since all features matching a Group By value need to arrive before any features (of any feature type or dataset) belonging to the next group, using Ordering with multiple feature types is more complicated than processing a single feature type.

Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.

One approach is to send all features through a Sorter, sorting on the expected Group By attribute. The Sorter is a feature-holding transformer, collecting all input features, performing the sort, and then releasing them all. They can then be sent through an appropriate filter (TestFilter, AttributeFilter, GeometryFilter, or others), which are not feature-holding, and will release the features one at a time to the transformer using Input is Ordered By, now in the expected order.

The processing overhead of sorting and filtering may negate the performance gains you will get from using Input is Ordered By. In this case, using Group By without using Input is Ordered By may be the equivalent and simpler approach.

In all cases when using Input is Ordered By, if you are not sure that the incoming features are properly ordered, they should be sorted (if a single feature type), or sorted and then filtered (for more than one feature or geometry type).

As with many scenarios, testing different approaches in your workspace with your data is the only definitive way to identify performance gains.

This filter is used to indicate which part on the Supplier geometry is to be used as the source Appearance Style. As well, if more than one Geometry Part match the Supplier Geometry XQuery filter, the first Geometry Part is used as the source of the appearance style.

You can specify which side of the Supplier geometry from which the source appearance style should be retrieved.

Front Side: The texture will be retrieved from the front side of the geometry only.

Back Side: The texture will be retrieved from the front side of the geometry only.

This filter is used to indicate onto which part on the Requestor geometry the Appearance Style is to be applied. The appearance is only directly set on the geometries which are specified through the Requestor Geometry XQuery selection. However, because appearances may be inherited further down a geometry hierarchy, setting an appearance directly at one level may have an effect further down a geometry hierarchy as well. Texture coordinates are therefore calculated, if necessary, on every geometry part that is affected by the setting of this appearance.

You can specify which side of the Supplier geometry from which the source appearance style should be retrieved.

Front Side: The texture will be applied to the front side of the geometry only.

Back Side: The texture will be applied to the front side of the geometry only.

Front and Back Sides: The texture will be applied to both sides of the geometry.

When an appearance with a raster texture is set, each part of the Geometry that is affected will also require texture coordinates. When this parameter is No, new texture coordinates are always calculated for each part of the geometry that is affected by the appearance which is being set. When this parameter is Yes, new texture coordinates are only calculated on the affected parts of the geometry where they do not already exist. Existing texture coordinates are left unchanged.

This parameter specifies how the texture defined in an appearance style will be mapped onto the surface. This is only applicable to textures which have raster images.

Surface Normal: The textures are projected onto the surfaces along their normals. For composite surfaces and meshes, each of the child parts will be treated separately, since the parts can have different normals.

From Top View: The textures are projected onto the surfaces along a single normal – one that is perpendicular to the x-y plane. In this mode, a composite surface is considered as one single geometry when the texture coordinates are applied.

You can specify how the texture is shifted in the u direction with this parameter.

You can specify how the texture is shifted in the v direction with this parameter.

Texture u Repeat Factor can be used to specify the number of times the texture is repeated in rows.

Texture v Repeat Factor can be used to specify the number of times the texture is repeated in columns.