[vtkusers] clipping a grid inside a complex structure

[Stefan Klemm]

Hi Dave,

I think you're right, clipping can not be efficient with that amount of
polys, and reducing them wouldn't help much.
I'll probably try to fiddle a little with OpenGL calls.
Thanks for your help!

Stefan


> 
> Stefan,
>    I would suggest finding the 'correct' way to use the stencil buffer
> inside vtk. Might take a bit of digging around inside vtk... At best you
> might get away with mixing OpenGL calls with vtk but I suspect you need a
> specialised vtkRender (etc). With the size of your problem this is
> probably
> your only hope for best speed.
> I have a vtk class that clips polydata with polydata, but it is not fast
> even for 100's of polygons. You are welcome to try it but I think you are
> better using your OpenGL knowledge.
> 
>   regards
>      Dave Pont
> 
>                                                                           
>                                     
>                       "Stefan Klemm"                                      
>                                     
>                       <Biele at quantentun        To:      
> "vtkusers at vtk.org" <vtkusers at vtk.org>                 
>                       nel.de>                  cc:                        
>                                     
>                       Sent by:                 Subject:  [vtkusers]
> clipping a grid inside a complex structure 
>                       vtkusers-admin at vt                                   
>                                     
>                       k.org                                               
>                                     
>                                     
>                       07/02/2004 06:25                                    
> 
> Hi,
> 
> I'm working on a java application with a ship swimming in a water surface
> (both are of vtkPolyData).
> My problem is that (when the deck of the ship is removed) you can see the
> water instead of the floor of the ship.
> 
> Is there a way of clipping exactly that part of the water surface that
> lies
> in the ship body?
> 
> The problem is that the ship consists of some thousand quadrilaterals and
> both water and ship are animated over time. Therefore I need some kind of
> implicit function to describe the ship volume which can be transformed
> later.
> I have tried to build an according implicit function using boolean
> operations but did not succeed.
> 
> I have managed the problem well using JOGL and the OpenGL stencil buffer.
> Could it be a reasonalbe solution to edit the C++ files in order to access
> the stencil buffer?
> 
> Any ideas are appreciated
> 
> Stefan
> 

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