[vtkusers] VTK rendering pipeline - ray casting

[Juan Carlos Prieto]

Hi Julien,

Yes the 3D position, so I'm now using the vtkPropPicker, this picker 
will actually give me the world position in the actor where the hit 
occurred.
I'm trying to solve another problem now. When I change the camera's 
position and view direction, the actor is not rendered unless I perform 
some interaction with the window (e.x. left click, zoom etc.), If I 
perform the pick then the result is empty.

The idea is to find a set of intersections given a set of rays, so I 
don't know how to update the view with out the interaction.

Is there a way to do this?

Le 30/09/2011 14:03, Julien Finet a écrit :
> Hi Juan,
> if you use a cellpicker, keep in mind that the volume ray caster is 
> under the hood a cube with 6 faces (technically, with 12triangular 
> faces). So you always pick the bounds of the volume.
> Are you sure you are interested in the cell and not the 3D position ?
> julien.
>
> On Fri, Sep 30, 2011 at 7:38 AM, Juan Carlos Prieto 
> <prieto at creatis.insa-lyon.fr <mailto:prieto at creatis.insa-lyon.fr>> wrote:
>
>     Hi Julien,
>
>     Thank you very much for the presentation, I kept on looking and I
>     saw that using a vtkCellPicker might do the job of finding the
>     intersection of a ray against an actor in a renderer.
>     To do this, I'm moving the camera to look in the direction where I
>     want the intersection to happen, but it seems that after producing
>     the pick, it always finds the same cell in the actor.
>
>     Can you give me some suggestion on how should I do this?
>
>     Thank you very much
>
>     Le 29/09/2011 20:22, Julien Finet a écrit :
>>     Hi Juan,
>>
>>
>>     You can find a GPU ray casting high level presentation in the
>>     Kitware Source of October 2009:
>>     http://www.kitware.com/products/archive/kitware_quarterly0708.pdf
>>
>>     Hth,
>>     Julien.
>>
>>     On Thu, Sep 29, 2011 at 11:54 AM, Juan Carlos Prieto
>>     <prieto at creatis.insa-lyon.fr
>>     <mailto:prieto at creatis.insa-lyon.fr>> wrote:
>>
>>         Dear VTK Users,
>>
>>         I was wondering if anyone can point me out to the
>>         documentation of the VTK rendering pipeline, I want to
>>         analyze how the ray casting is done as I came across a little
>>         problem where I need find the point of intersection in the
>>         surface.
>>
>>         Thank you very much.
>>
>>         -- 
>>         Juan Carlos Prieto
>>         Phd Student
>>         CREATIS <http://www.creatis.insa-lyon.fr> Tel:+33472438918
>>         <tel:%2B33472438918>
>>         7 Av Jean Capelle
>>         69621 Villeurbanne Cedex
>>         France
>>         Personal page <http://www.creatis.insa-lyon.fr/%7Eprieto>
>>
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>
>     -- 
>     Juan Carlos Prieto
>     Phd Student
>     CREATIS <http://www.creatis.insa-lyon.fr> Tel:+33472438918
>     <tel:%2B33472438918>
>     7 Av Jean Capelle
>     69621 Villeurbanne Cedex
>     France
>     Personal page <http://www.creatis.insa-lyon.fr/%7Eprieto>
>
>

-- 
Juan Carlos Prieto
Phd Student
CREATIS <http://www.creatis.insa-lyon.fr> Tel:+33472438918
7 Av Jean Capelle
69621 Villeurbanne Cedex
France
Personal page <http://www.creatis.insa-lyon.fr/%7Eprieto>
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