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.

Process At End (Blocking): This is the default behavior. Processing will only occur in this transformer once all input is present.

Process When Group Changes (Advanced): This transformer will process input groups in order. Changes of the value of the Group By parameter on the input stream will trigger processing on the currently accumulating group. This may improve overall speed (particularly with multiple, equally-sized groups), but could cause undesired behavior if input groups are not truly ordered.

Considerations for Using Group By

There are two typical reasons for using Process When Group Changes (Advanced) . The first is incoming data that is intended to be processed in groups (and is already so ordered). In this case, the structure dictates Group By usage - not performance considerations.

The second possible reason is potential performance gains.

Performance gains are most likely when the data is already sorted (or read using a SQL ORDER BY statement) since less work is required of FME. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains).

Sorting becomes more difficult according to the number of data streams. Multiple streams of data could be almost impossible to sort into the correct order, 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. In this case, using Group By with Process At End (Blocking) may be the equivalent and simpler approach.

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

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.