Get intersect point between mesh with Ray (c++)

suc_kiet · October 2, 2018, 7:27pm

Hi;
In Rhinocommon I can use this funtion : Intersection.MeshRay Method (Mesh, Ray3d,Int32), find the faces which intersect with the Ray, but I search the Rhino c++ sdk along time, I was not found the funtion like it, how cant I solve it?

dale · October 3, 2018, 1:09am

Hi @suc_kiet,

Use the ON_RayShooter class. See opennurbs_plus.h for it’s declaration.

– Dale

suc_kiet · October 3, 2018, 8:12am

Hi@dale;
I have see it, in ON_RayShooter class, just have the funtion abaut surface.

So I must change the mesh to surface first?

dale · October 31, 2018, 7:20pm

Hi @suc_kiet,

Let me know if this sample code helps.

github.com

mcneel/rhino-developer-samples/blob/6/cpp/SampleCommands/cmdSampleIntersectMeshRay.cpp

#include "stdafx.h"

/*
Description:
  Finds the first intersection of a ray with a mesh.
Parameters:
  mesh         - [in]   - A mesh to intersect.
  ray          - [in]   - A ray to be casted.
  face_indices - [out]  - Faces on mesh that ray intersects (can be nullptr).
Returns:
  >= 0.0 parameter along ray if successful. < 0.0 if no intersection found.
Remarks:
  The ray may intersect more than one face in cases where the ray hits the edge
  between two faces or the vertex corner shared by multiple faces.
*/
double SampleIntersectMeshRay(const ON_Mesh* mesh, ON_3dRay* ray, ON_SimpleArray<int>* face_indices)
{
  double rc = -1.0;
  if (mesh && ray)
  {

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– Dale