Juan:<div><br></div><div>You would use the vtkVolumePicker (or even the vtkCellPicker, although it ignores the cropping planes); not the prop picker, to pick the volume at a given "opacity iso-surface". (SetVolumeOpacityIsoValue and UseVolumeGradientOpacity)<div>
<div><br></div><div>It would have been better instead to do that based on the accumulated opacity along the ray, until it reached a stopping opacity. I'll try to add that at some point.</div><div><br></div><div>But you can pick volumes.</div>
<div><br></div><div>--</div><div>karthik<br><br><div class="gmail_quote">On Fri, Sep 30, 2011 at 6:20 PM, Juan Carlos Prieto <span dir="ltr"><<a href="mailto:prieto@creatis.insa-lyon.fr">prieto@creatis.insa-lyon.fr</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><u></u>
<div bgcolor="#ffffff" text="#000000">
Hi Julien, <br>
<br>
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. <br>
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. <br>
<br>
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. <br>
<br>
Is there a way to do this?<br>
<br>
Le 30/09/2011 14:03, Julien Finet a écrit :
<div><div></div><div class="h5"><blockquote type="cite">Hi Juan,
<div>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.</div>
<div>Are you sure you are interested in the cell and not the 3D
position ?</div>
<div>julien.<br>
<br>
<div class="gmail_quote">On Fri, Sep 30, 2011 at 7:38 AM, Juan
Carlos Prieto <span dir="ltr"><<a href="mailto:prieto@creatis.insa-lyon.fr" target="_blank">prieto@creatis.insa-lyon.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
<div bgcolor="#ffffff" text="#000000"> Hi Julien, <br>
<br>
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. <br>
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. <br>
<br>
Can you give me some suggestion on how should I do this? <br>
<br>
Thank you very much<br>
<br>
Le 29/09/2011 20:22, Julien Finet a écrit :
<div>
<div>
<blockquote type="cite">Hi Juan,
<div><br>
</div>
<div><br>
</div>
<div>You can find a GPU ray casting high level
presentation in the Kitware Source of October
2009:
<div><a href="http://www.kitware.com/products/archive/kitware_quarterly0708.pdf" target="_blank">http://www.kitware.com/products/archive/kitware_quarterly0708.pdf</a></div>
<div><br>
</div>
<div>Hth,</div>
<div>Julien.<br>
<br>
<div class="gmail_quote">On Thu, Sep 29, 2011 at
11:54 AM, Juan Carlos Prieto <span dir="ltr"><<a href="mailto:prieto@creatis.insa-lyon.fr" target="_blank">prieto@creatis.insa-lyon.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
<div bgcolor="#ffffff" text="#000000"> Dear
VTK Users, <br>
<br>
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. <br>
<br>
Thank you very much. <br>
<font color="#888888"> <br>
<div>-- <br>
Juan Carlos Prieto <font face="arial" color="grey" size="2"> <br>
Phd Student <br>
<a href="http://www.creatis.insa-lyon.fr" target="_blank">CREATIS</a> Tel:<a href="tel:%2B33472438918" value="+33472438918" target="_blank">+33472438918</a> <br>
7 Av Jean Capelle <br>
69621 Villeurbanne Cedex <br>
France <br>
<a href="http://www.creatis.insa-lyon.fr/%7Eprieto" target="_blank">Personal page</a>
</font> </div>
</font></div>
<br>
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</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
<div>-- <br>
Juan Carlos Prieto <font face="arial" color="grey" size="2"> <br>
Phd Student <br>
<a href="http://www.creatis.insa-lyon.fr" target="_blank">CREATIS</a> Tel:<a href="tel:%2B33472438918" value="+33472438918" target="_blank">+33472438918</a>
<br>
7 Av Jean Capelle <br>
69621 Villeurbanne Cedex <br>
France <br>
<a href="http://www.creatis.insa-lyon.fr/%7Eprieto" target="_blank">Personal page</a> </font> </div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</blockquote>
<br>
<div>-- <br>
Juan Carlos Prieto
<font face="arial" color="grey" size="2">
<br>
Phd Student
<br>
<a href="http://www.creatis.insa-lyon.fr" target="_blank">CREATIS</a>
Tel:+33472438918
<br>
7 Av Jean Capelle
<br>
69621 Villeurbanne Cedex
<br>
France <br>
<a href="http://www.creatis.insa-lyon.fr/%7Eprieto" target="_blank">Personal
page</a>
</font>
</div>
</div></div></div>
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