原文发布时间：2010-06-25
作者：毛毛虫
下面说一下转换器Extruder
该转换器的功能是使用固定的横截面剖面，从要素的原始几何创建长度、表面或立体几何。转换器属性如下：
输入：1）如果输入的要素是表面（face）或面（area），则输出的是立体几何；2）如果输入的是线性要素，则输出的是复合表面（composite surface）几何。
通过对查询几何属性可以看出：
例如对于下面的图层：
转换前的某个要素的几何属性如下：
Coord Dimension: 2D
Total Number of Coords: 5
Bounding Box:
Lower Left: (490765.871181,5459423.5587614)
Upper Right: (490799.2348479,5459456.9671378)
Coordinate Listing:
----------------------------------
1: (490779.4495152, 5459423.5587614)
2: (490765.871181, 5459437.0414524)
3: (490785.6565137, 5459456.9671378)
4: (490799.2348479, 5459443.4844467)
5: (490779.4495152, 5459423.5587614)
假设转换前的几何类型为fme_area，则转换后该要素的几何属性为：
Bounding Cube:
Lower Left: (490765.871181,5459423.5587614)
Upper Right: (490799.2348479,5459456.9671378)
Z Range: 0.0 to 21.0
Geometry Type: IFMEExtrusion
Base:
Geometry Type: IFMEFace
Sidedness: `1-sided'
Front Appearance Reference: `<no_appearance>'
Area:
Geometry Type: IFMEPolygon
Boundary:
Geometry Type: IFMELine
Number of Coordinates: 5 -- Coordinate Dimension: 3
0: (490779.449515215,5459423.55876139,0)
1: (490765.871181019,5459437.04145245,0)
2: (490785.656513688,5459456.96713775,0)
3: (490799.234847883,5459443.48444669,0)
4: (490779.449515215,5459423.55876139,0)
Extrusion vector: <0,0,21>
而转换前的几何类型为fme_line，则转换后该要素的几何属性为：
Bounding Cube:
Lower Left: (490765.871181,5459423.5587614)
Upper Right: (490799.2348479,5459456.9671378)
Z Range: 0.0 to 21.0
Geometry Type: IFMECompositeSurface
Sidedness: `1-sided'
Front Appearance Reference: `<no_appearance>'
Number of Surfaces: 4
--------------------------------------
Surface Number: 0
Geometry Type: IFMEFace
Sidedness: `1-sided'
Front Appearance Reference: `<no_appearance>'
Area:
Geometry Type: IFMEPolygon
Boundary:
Geometry Type: IFMELine
Number of Coordinates: 5 -- Coordinate Dimension: 3
0: (490779.449515215,5459423.55876139,0)
1: (490765.871181019,5459437.04145245,0)
2: (490765.871181019,5459437.04145245,21)
3: (490779.449515215,5459423.55876139,21)
4: (490779.449515215,5459423.55876139,0)
--------------------------------------
Surface Number: 1
Geometry Type: IFMEFace
Sidedness: `1-sided'
Front Appearance Reference: `<no_appearance>'
Area:
Geometry Type: IFMEPolygon
Boundary:
Geometry Type: IFMELine
Number of Coordinates: 5 -- Coordinate Dimension: 3
0: (490765.871181019,5459437.04145245,0)
1: (490785.656513688,5459456.96713775,0)
2: (490785.656513688,5459456.96713775,21)
3: (490765.871181019,5459437.04145245,21)
4: (490765.871181019,5459437.04145245,0)
--------------------------------------
Surface Number: 2
Geometry Type: IFMEFace
Sidedness: `1-sided'
Front Appearance Reference: `<no_appearance>'
Area:
Geometry Type: IFMEPolygon
Boundary:
Geometry Type: IFMELine
Number of Coordinates: 5 -- Coordinate Dimension: 3
0: (490785.656513688,5459456.96713775,0)
1: (490799.234847883,5459443.48444669,0)
2: (490799.234847883,5459443.48444669,21)
3: (490785.656513688,5459456.96713775,21)
4: (490785.656513688,5459456.96713775,0)
--------------------------------------
Surface Number: 3
Geometry Type: IFMEFace
Sidedness: `1-sided'
Front Appearance Reference: `<no_appearance>'
Area:
Geometry Type: IFMEPolygon
Boundary:
Geometry Type: IFMELine
Number of Coordinates: 5 -- Coordinate Dimension: 3
0: (490799.234847883,5459443.48444669,0)
1: (490779.449515215,5459423.55876139,0)
2: (490779.449515215,5459423.55876139,21)
3: (490799.234847883,5459443.48444669,21)
4: (490799.234847883,5459443.48444669,0)
参数Extrusion Input By：挤压的数量可以设置为heigh（这种情况下挤压用在z轴的正方向上），或者设置为一个挤压矢量（这种情况用于任意方向的挤压）。
例如：
还是对于上面的面图层，部分图层显示如下：
设置Extruder如下：
则得到的图层为：
查看某一要素的几何属性如下：
Bounding Cube:
Lower Left: (490492.249543,5459443.0838149)
Upper Right: (490545.6033648,5459486.4947023)
Z Range: 0.0 to 0.0
Geometry Type: IFMEExtrusion
Base:
Geometry Type: IFMEFace
Sidedness: `1-sided'
Front Appearance Reference: `<no_appearance>'
Area:
Geometry Type: IFMEPolygon
Boundary:
Geometry Type: IFMELine
Number of Coordinates: 5 -- Coordinate Dimension: 3
0: (490508.620476774,5459443.08381495,0)
1: (490492.249542972,5459459.36789237,0)
2: (490519.23243095,5459486.49470229,0)
3: (490535.603364751,5459470.21062486,0)
4: (490508.620476774,5459443.08381495,0)
Extrusion vector: <10,0,0>
类似于3Daffine转换器的表示，转换矢量为<10,0,0>，即在x轴方向增厚了10。为了看的更加清楚，叠加原图层后的效果如下（蓝色为原图层）：
注意：转换器Extruder只对表面（face）、面（area）和线（line）有影响。