[vtkusers] vtkCellLocator::IntersectWithLine

[Obada Mahdi]

Hi Matthew!

On Wed, 25 Jan 2006, Matthew DiFranco wrote:
 > I've noticed that there is a serious lack of explanation in the
 > documentation for vtkCellLocator::IntersectWithLine. I would like to
 > find the intersection of a line with a vtkPolyData surface. Can
 > someone explain what the inputs of said method represent?

I'll give it a try:

| int
| vtkCellLocator::IntersectWithLine(
| 	double a0[3], double a1[3], double tol,
| 	double &t, double x[3], double pcoords[3], int &subId)

This method takes as input:
- `a0' and `a1': (global) coordinates of the two endpoints of the finite
   line segment to be intersected with
- `tol': tolerance (directly in "units" of the coordinate system)

It produces:
- return value: non-zero if there was an intersection, in that case the
   following return parameters hold:
- `t': parametric coordinate along the line segment where the
   intersection occurred
- `x': global coordinates of the intersection
- `pcoords': same coordinates in parametric representation
- `subId': sub-ID of intersected cell

I am not entirely sure, any corrections are welcome.  Might help you to
get on the right track, though.


Regards

Obada