【NX二次开发】判断面是否相切，相切面。

判断面是否相切，相切面。

用到的函数：

UF_MODL_ask_minimum_dist 获取两个对象之间的最短距离，以及点坐标
UF_MODL_ask_face_parm    给定一个参考点，返回曲面上的面参数(u,v)，以及点。
UF_MODL_ask_face_props   输入面、面的uv参数。输出此位置的面法线

源码：

bool bool_is_Tangent(tag_t tagFace1, tag_t tagFace2);
extern DllExport void ufsta(char *param, int *returnCode, int rlen)
{
    UF_initialize();
    tag_t tag_Face1 = 46607;
    tag_t tag_Face2 = 47338;
    if (bool_is_Tangent(tag_Face1, tag_Face2))
    {
        uc1601("相切", 1);
    }
    else
    {
        uc1601("不相切", 1);
    }
    UF_terminate();
}

extern int ufusr_ask_unload(void)
{
    return (UF_UNLOAD_IMMEDIATELY);
}
bool bool_is_Tangent(tag_t tagFace1, tag_t tagFace2)
{
    double guess1[3] = { 0.0,0.0,0.0 };
    double guess2[3] = { 0.0,0.0,0.0 };
    double  min_dist = 0.0;
    double pt_on_ent1[3] = { 0.0,0.0,0.0 };
    double pt_on_ent2[3] = { 0.0,0.0,0.0 };
    UF_MODL_ask_minimum_dist(tagFace1, tagFace2, 0, guess1, 0, guess2, &min_dist, pt_on_ent1, pt_on_ent2);
    if (min_dist > 0.01)
    {
        return false;
    }
    double param1[2] = { 0.0,0.0 };//面部参数(u,v)
    double param2[2] = { 0.0,0.0 };//面部参数(u,v)
    UF_MODL_ask_face_parm(tagFace1, pt_on_ent1, param1, pt_on_ent1);
    UF_MODL_ask_face_parm(tagFace2, pt_on_ent2, param2, pt_on_ent2);

    double u1[3] = { 0.0,0.0,0.0 };
    double v1[3] = { 0.0,0.0,0.0 };
    double u2[3] = { 0.0,0.0,0.0 };
    double v2[3] = { 0.0,0.0,0.0 };
    double fx_1[3] = { 0.0,0.0,0.0 };//面法线
    double fx_2[3] = { 0.0,0.0,0.0 };//面法线
    double radii[2] = { 0.0,0.0 };
    
    //输入面，面的uv参数。输出此位置的面法线
    UF_MODL_ask_face_props(tagFace1, param1, pt_on_ent1, u1, v1, u2, v2, fx_1, radii);
    UF_MODL_ask_face_props(tagFace2, param2, pt_on_ent2, u2, v2, u2, v2, fx_2, radii);

    double dTolerance = 0.01;    //相切公差
    if (fabs(fabs(fx_1[0]) - fabs(fx_2[0])) < dTolerance
        && fabs(fabs(fx_1[1]) - fabs(fx_2[1])) < dTolerance
        && fabs(fabs(fx_1[2]) - fabs(fx_2[2])) < dTolerance)
    {
        return true;
    }
    else
    {
        return false;
    }
}

效果：