SurfaceOnSurfaceOverlayer
Performs a surface-on-surface overlay so that all input surfaces are intersected against each other and resultant surface features are created and output.The output surfaces can retain all the attributes of the input features in which they are contained.
All surfaces are broken down into faces.For example, a mesh is broken into faces, one face per mesh part.
Non-surface input features are not supported.Input collections of surfaces are automatically de-aggregated.
Input Ports
Surface features.
Output Ports
Surface features are output here.
Parameters
The default behavior is to use the entire set of features as the group.This option allows you to select attributes that define which groups to form.
过程在结束(封闭): This is the default behavior.Processing will only occur in this transformer once all input is present.
过程当组更改(高级): 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.
There are two typical reasons for using过程当组更改(高级).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.
第二个原因可能是潜在的性能提升。
性能提升是最有可能当数据已经排序(或使用阅读SQL ORDER BY声明),因为更少的工作需要FME的。如果数据需要排序,它可以在工作区中进行排序(虽然增加的处理开销可能会抵消任何收益)。
排序根据数据流的数目变得更困难。多个数据流可以几乎是不可能的排序到正确的顺序,因为所有的功能匹配通过...分组值需要到达之前的任何特征属于下一组(任何特征类型或数据集的)。在这种情况下,使用通过...分组同过程在结束(封闭)可能是等效的和简单的方法。
注意:多种要素类型和特点从多个数据集通常不会自然出现在正确的顺序。
如同许多情况下,在您的工作与你的数据测试不同的方法是确定性能提升的唯一准确的方法。
TheOverlap Count Attributeholds the number of input surfaces that contain each output surface.This count will be 1 or greater.
If set toYes, theNormal Tolerance in DegreesandOffset Toleranceparameters are enabled.If set toNo, the two parameters are disabled.
Faces must be parallel before they are allowed to cut into each other.If two faces are nearly parallel with normals that are slightly apart, use this parameter to set a tolerance in degrees.The larger the value, the less parallel the faces would have to be while still considered parallel to each other.
Usage Tip: Use this parameter together withOffset Tolerance.
Faces must be co-planar before they are allowed to cut into each other.If two faces are nearly co-planar, but are a small offset from each other, use this parameter to set a tolerance in ground units.The larger the value, the farther away the faces could be while still considered co-planar.
Usage Tip: Use this parameter together withNormal Tolerance in Degrees.
Attribute Accumulation
Specifies how attributes should be accumulated.IfDrop Incoming Attributesis selected, all incoming attributes are removed from the features.Merge Incoming Attributesmerges all attributes from overlapping features.Use Attributes From One Featuretakes all attributes from one representative feature.
Allows you to specify aList Name.
If aList Nameis supplied, for each output feature, a list is created of all the attributes of input features that contain the output feature.A list with the same name is created fortraits.
注意:List attributesare not accessible from the output schema in Workbench unless they are first processed using a transformer that operates on them, such asListExploderorListConcatenator.Alternatively,AttributeExposercan be used.
All Attributes: Every attribute from all input features that created an output surface will be added to the list specified inList Name.
Selected Attributes: Only the attributes specified in theSelected Attributesparameter will be added to the list specified inList Name.
The attributes to be added to the list whenAdd To ListisSelected Attributes.
Example:
Usage Notes
Aggregates are not supported by this transformer.
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace.More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers.To access a menu of these options, clickbeside the applicable parameter.For more information, seeTransformer Parameter Menu Options.
Transformer Categories
FME Licensing Level
FME Professional edition and above
FME Community
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