Object 1	Object 2	Intersection Information
Point	Point, Curve, Edge, Datum Axis, Plane, Datum Plane, Face	Point Information
Curve, Edge,  Datum Axis	Curve, Edge, Datum Axis, Plane, Datum Plane, Face	Point Information,  A coincident curve
Plane,  Datum Plane, Face	Plane, Datum Plane, Face	Point Information,  An intersection curve
Body	Plane, Datum Plane, Face	An intersection curve

 
The caller is responsible to delete the curves that have been created by this function.
 
An intersection between two points is returned if the distance between the input points is within the input tolerance.
 
No attempt is made to find regions of coincidence between faces and planes. If the only intersection between faces/planes is a coincidence then no intersection is returned.
 
Multiple intersections at a point on a curve where it intersects itself is returned only when the other object is a point or plane.
 
The following structure is used to pass back the information needed to describe the intersection between the two objects.
 
typedef struct UF_MODL_intersect_info_s
{
     UF_MODL_intersect_type_t intersect_type;
     union
    {
          /*intersect_type == UF_MODL_INTERSECT_POINT*/
          struct
         {
                double coords[3];
                double object_1_u_parm;
                double object_1_v_parm;
                double object_2_u_parm;
                double object_2_v_parm;
          } point;
 
          /*intersect_type == UF_MODL_INTERSECT_COINCIDE*/
         struct
         {
               tag_t identifier;
               double object_1_first_parm;
               double object_1_second_parm;
               double object_2_first_parm;
               double object_2_second_parm;
          } coincide;
 
          /*intersect_type == UF_MODL_INTERSECT_CURVE*/
          struct
         {
               tag_t identifier;
          } curve;
 
      } intersect;
} UF_MODL_intersect_info_t,  *UF_MODL_intersect_info_p_t;
 
 

Field	Description
intersect_type	indication of type of intersection that occurred, either a intersection point, a coincident curve, or a intersection curve. This is set to one of the following values: UF_MODL_INTERSECT_POINT UF_MODL_INTERSECT_COINCIDE UF_MODL_INTERSECT_CURVE
point	Information used to describe the intersection if intersection_type = UF_MODL_INTERSECT_POINT, note that the parameter values are defined only as specified below, otherwise they are set to 0. The parameter values for the edge correspond to a curve that can be created from the edge using UF_MODL_create_curve_from_edge. coords[3] absolute coordinates of the intersection point object_1_u_parm U parameter value of the intersection on  object 1 if object 1 is a curve, edge or face. object_1_v_parm V parameter value of the intersection on  object 1 if object 1 is a face. object_2_u_parm U parameter value of the intersection on  object 2 if object 2 is a curve, edge or face. object_2_v_parm V parameter value of the intersection on  object 2 if object 2 is a face.
coincide	Information used to describe the intersection if intersection_type = UF_MODL_COINCIDENT_CURVE, note that the parameter values are defined only when the object is a curve or edge, otherwise they are set to 0. The parameter values for the edge correspond to a curve that can be created from the edge using UF_MODL_create_curve_from_edge. identifier - the identifier of a curve that was created at  the coincidence of the two objects,  the caller is responsible for deleting this curve. object_1_first_parm parameter value of the start of the coincident curve on object 1. object_1_second_parm parameter value of the end of the  coincident curve on object 1. object_2_first_parm parameter value of the start of the coincident curve on object 2. object_2_second_parm parameter value of the end of the  coincident curve on object 2.
curve	Information used to describe the intersection if intersection_type = UF_MODL_INTERSECT_CURVE: identifier - the identifier of a curve that was created at  the intersection of the two objects, the caller is responsible for deleting this curve.

 
The following example requires a blank, open part. The code creates a B-surface, arc, and two lines. One line intersects the B-surface and the other line is coincident to an edge. The arc intersects the B-surface twice.

#include <stdio.h>
#include <uf_modl.h>
#include <uf.h>
#include <uf_obj.h>
#include <uf_curve.h>
#include <uf_defs.h>
#include <uf_csys.h>

#define UF_CALL(X) (report( __FILE__, __LINE__, #X, (X)))

static void get_intersect(tag_t curve, tag_t face, double tol);

static int report( char *file, int line, char *call, int irc)
{
  if (irc)
  {
     char    messg[133];

     printf("%s, line %d:  %s\n", file, line, call);

     (UF_get_fail_message(irc, messg)) ?
       printf("    returned a %d\n", irc) :
       printf("    returned error %d:  %s\n", irc, messg);
  }
  return(irc);
}

static void do_ugopen_api(void)
{
  tag_t base_sheet_id, line_id;
  tag_t face, arc_tag, line2_id;

  int num_pole_u = 4;
  int num_pole_v = 4;
  int u_ord = 4;
  int v_ord = 4;
  int knot_fix;
  int pole_fix;

  int i, j, k = 0;

  UF_CURVE_line_t line_coords  = {1.5,1.5,-2,1.5,1.5,1.0};
  UF_CURVE_line_t line_coords2 = {0.0, 3.0, 0.0};
  UF_CURVE_arc_t arc_coords = {NULL_TAG,0.0,180*DEGRA,1.5,0.0,-1.5,0.25};

  uf_list_p_t list;

  double weight = 1.0;
  double u_knot[9] = {0.0,0.0,0.0,0.0,1.0,1.0,1.0,1.0,1.0};
  double v_knot[9] = {0.0,0.0,0.0,0.0,1.0,1.0,1.0,1.0,1.0};
  double pole[64];

  double tol = .001;

  double matrix_values[9] = {1.0, 0.0, 0.0,
                             0.0, 0.0, 1.0,
                             0.0, 1.0, 0.0};

  /* Create pole array data. */
  for (i = 0; i < 4; i++) {
    for (j = 0; j < 4; j++) {
      pole[k++] = i;
      pole[k++] = j;
      pole[k++] = 0.0;
      pole[k++] = weight;
    }
  }

  /* Create base surface. */
  UF_CALL(UF_MODL_create_bsurf(num_pole_u, num_pole_v, u_ord, v_ord,
                               u_knot, v_knot,pole,&base_sheet_id,
                               &knot_fix,&pole_fix));

  /* Get faces. */
  UF_CALL(UF_MODL_ask_body_faces(base_sheet_id,&list));
  UF_CALL(UF_MODL_ask_list_item(list,0,&face));
  UF_CALL(UF_MODL_delete_list(&list));

  /* Create line. */
  UF_CALL(UF_CURVE_create_line(&line_coords,&line_id));

  /* Get line intersection. */
  get_intersect(line_id, face, tol);
 
  /* Create coincident line. */
  UF_CALL(UF_CURVE_create_line(&line_coords2,&line2_id));
  UF_CALL(UF_OBJ_set_color(line2_id, UF_OBJ_YELLOW));

  /* Get coincident line intersection data */
  get_intersect(line2_id, face, tol);

  /* Create arc. */
  UF_CALL(UF_CSYS_create_matrix(matrix_values,&arc_coords.matrix_tag));
  UF_CALL(UF_CURVE_create_arc(&arc_coords, &arc_tag));

  /* Get arc intersection. */
  get_intersect(arc_tag, face, tol);
}

/*ARGSUSED*/
void ufusr(char *param, int *retcode, int param_len)
{
  if (!UF_CALL(UF_initialize()))
  {
    do_ugopen_api();
    UF_CALL(UF_terminate());
  }
}

int ufusr_ask_unload(void)
{
  return (UF_UNLOAD_IMMEDIATELY);
}

static void get_intersect(tag_t curve, tag_t face, double tol)
{
  int num_intersects, type, i;
  UF_MODL_intersect_info_p_t *intersect_data;

  UF_CALL(UF_MODL_intersect_objects(curve,face,tol,&num_intersects,&intersect_data));

  printf("\n Number of intersections = %d\n", num_intersects);

  for(i = 0; i < num_intersects; i++)
  {
    type = (intersect_data[i])->intersect_type;

    switch(type)
    {
      case UF_MODL_INTERSECT_POINT:

        printf("\nx,y,z coordinates are: (%f, %f, %f)\n",
               (intersect_data[i])->intersect.point.coords[0],
               (intersect_data[i])->intersect.point.coords[1],
               (intersect_data[i])->intersect.point.coords[2]);

        printf("Object 1 UV parameters are: (%f, %f)\n",
               (intersect_data[i])->intersect.point.object_1_u_parm,
               (intersect_data[i])->intersect.point.object_1_v_parm);

        printf("Object 2 UV parameters are: (%f, %f)\n",
               (intersect_data[i])->intersect.point.object_2_u_parm,
               (intersect_data[i])->intersect.point.object_2_v_parm);

        break;
 
      case UF_MODL_INTERSECT_COINCIDE:

        printf("\nCoincident curve tag is: %d\n",
               intersect_data[i]->intersect.coincide.identifier);

        printf("Object 1 UV parameters are: (%f, %f)\n",
               intersect_data[i]->intersect.coincide.object_1_first_parm,
               intersect_data[i]->intersect.coincide.object_1_second_parm);

        printf("Object 2 UV parameters are: (%f, %f)\n",
               intersect_data[i]->intersect.coincide.object_2_first_parm,
               intersect_data[i]->intersect.coincide.object_2_second_parm);
        break;

      case UF_MODL_INTERSECT_CURVE:

        printf("\nThe curve identifier is: %d\n",
               (intersect_data[i])->intersect.curve.identifier);
        break;

      default:

        printf("\nSomething went wrong, we shouldn't be here!");
        break;
    }

    /* Free each element of the array. */
      UF_free(intersect_data[i]);
  }

  if(num_intersects != 0)
  {
    /* Free the array. */
    UF_free(intersect_data);
  }
}