CityEngine CGA语法之 随机点函数 scatter

概要

scatter(domain, nPoints, distributionType) { operations }

scatter(domain, nPoints,gaussian, scatterMean, scatterStddev) { operations } 

参数

domain (selstr)：指定随机点产生的位置，有三个选项：surface、volume、scope。
nPoints (float)：指定点的数量
distributionType (selstr)：指定点分布的类型，有两个选项：uniform、gaussian
scatterMean (selstr)：可选的参数，指定随机点群的中心相对于当前的scope的位置，有七个选项center、front、back、left、right、top、bottom，默认为center
scatterStddev (float)：可选的参数，指定标准差，默认值是0.16. 

注意

只有在几何体是闭合的形状时，domain才能使用volume，如果不是闭合的，则会采用surface

产生的每一个点的scope的尺寸为0

产生的每一个点只包含一个节点，可以使用替换函数i()来插入模型

示例

一、在表面生成随机点，类型为uniform

attr height   =10
Lot-->extrude(height)scatter(surface,1000,uniform) {A.}

二、在体内生成随机点，类型为uniform

attr height   =10
Lot-->extrude(height)scatter(volume,1000,uniform) {A.}

三、在表面生成随机点，类型为gaussian

attr height   =10
Lot-->extrude(height)scatter(surface,1000,gaussian) {A.}

四、在体内生成随机点，类型为gaussian

attr height   =10
Lot-->extrude(height)scatter(volume,1000,gaussian) {A.}

五、在scope生成随机点，类型为uniform

attr height   =10
Lot-->extrude(height)scatter(scope,1000,<span style="font-size:14px;">uniform</span>) {A.}

六、在scope生成随机点，类型为gaussian

attr height   =10
Lot-->extrude(height)scatter(scope,1000,gaussian) {A.}

七、在scope生成随机点，类型为uniform,设置scatterMean参数

scatterMean为front

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,front,0.9) {A.}

\

scatterMean为left

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,left,0.9) {A.}

scatterMean为bottom

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,bottom,0.9) {A.}

scatterMean为right

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,right,0.9) {A.}

scatterMean为back

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,back,0.9) {A.}

scatterMean为top

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,top,0.9) {A.}

八、设置标准差

标准差越大，点越分散

设置标准差为0.2

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,top,0.2) {A.}

设置标准差为2

attr height   =10
Lot-->extrude(height)scatter(scope,20,gaussian,top,2) {A.}