Houdini VEX：几何体函数

addpoint()	添加点到几何体
addvertex()	添加顶点到几何体上的面
addprim()	添加面到几何体
removepoint()	删除点
removeprim()	删除面
removevertex()	删除顶点

使用add创建一个四角锥或者Attribute Wrangle创建一个四角锥，注意面法线方向。

int p0 = addpoint(geoself(), {1, 0, 1});
int p1 = addpoint(geoself(), {1, 0, -1});
int p2 = addpoint(geoself(), {-1, 0, 1});
int p3 = addpoint(geoself(), {-1, 0, -1});
int p4 = addpoint(geoself(), {0, 1.5, 0});

addprim(geoself(), "poly", p0, p1, p3, p2);
addprim(geoself(), "poly", p2, p4, p0);
addprim(geoself(), "poly", p0, p4, p1);
addprim(geoself(), "poly", p1, p4, p3);
addprim(geoself(), "poly", p3, p4, p2);

if (@P.x < 0) {
    removepoint(geoself(), @ptnum);
}

for (int i = 0; i < chi("num"); i++) {
    addpoint(geoself(), set(0, 0, i * chf("size")));
}

setprimintrinsic() setvertexpoint(0, 2, 0, 0);

primvertices() primvertex() primvertexcount() primpoints() primpoint()

pointprims() pointvetices() pointvertex() vertexpoint() vertexprev() vertexnext() vertexindex() vertexprim() vertexprimindex()

顶点序号

线性顶点序号

int lvt0 = pointvertex(0, 7);
int lvt1 = pointvertex(0, lvt0);
int lvt2 = pointvertex(0, lvt1);

setvertexattrib(0, "Cd", -1, lvt0, {1, 0, 0});
setvertexattrib(0, "Cd", -1, lvt1, {0, 1, 0});
setvertexattrib(0, "Cd", -1, lvt2, {0, 0, 1});