[vtkusers] vtkPointLocator & Collision avoidance

[Tim Hutton]

Hi Siddu,

Try putting BuildLocator before the call to FindClosestPointsWithinRadius.

(You may also need to do a STLReader->Update() before the call to 
BuildLocator.)

For collision detection a thorough approach would be to tetrahedralize if 
necessary all your objects so they are represented as solids (not just as 
surface meshes) and then use vtkCellLocator::FindClosestPoint to detect if 
each point is inside a cell.

Good luck,

Tim.


At 14:17 10/10/2002 +0100, Mysore Siddu wrote:

>  Hi vtk Users,
>
>  I have two questions:
>
>  <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
>
>1.      From cellLocator->IntersectWithLine I compute the intersection 
>point and its cellID on the STL file. Now I want to find all the points 
>within a radius around the intersection point. I tried using 
>vtkPointLocator::FindPointsWithinRadius(radius, point, vtkIdList *result) 
>But I was not successful with the following code:
>
>                   float p1[] = {2.0, 1.0, 3.0};
>
>float rad = 2.0;
>
>vtkIdList *res;
>
>// Build a locator
>
>vtkPointLocator *pointLocator = vtkPointLocator::New();
>
>pointLocator->SetDataSet(STLReader->GetOutput());
>
>pointLocator->FindPointsWithinRadius(rad,p1,res);
>
>pointLocator->BuildLocator();
>
>  I dont know where I am goofing up the code. As soon as Execute I am 
> getting error as Memory cant be assigned error I debugged the code it is 
> stopping at  vtkIdList.h // Description:
>
>// Reset to an empty state.
>
>void Reset() {this->NumberOfIds = 0;};
>
>*/
>
>
>
>
>
>2.      Is there any vtk class, which I can use for collision avoidance? 
>Basically I have two STL files and I want to check the collision around a 
>particular point.
>
>
>
>Any Help in this regard is very well appreciated.
>
>  Best Regards
>
>Siddu.

---------------------------------------------------------------------------
Tim Hutton,                        http://www.eastman.ucl.ac.uk/~dmi/MINORI
Research Fellow & PhD student,                   T.Hutton at eastman.ucl.ac.uk
MINORI Project, Biomedical Informatics Unit,     Tel: [+44] (0)20 7915 2344
Eastman Dental Institute, UCL,                   Fax: [+44] (0)20 7915 2303
256 Gray's Inn Road, London WC1X 8LD, UK      Mobile: [+44] (0)7748 678 832
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