[vtkusers] vtkPropPicker tolerance?

[Julian Ibarz]

2008/7/28 Sercani <sercanimailgroups at gmail.com>

>  Hi Julian;
>
> Thanks for your reply, I've looked at vtkVisibleCellSelection class and
> your bug patches, it is really what I need but I don't know how to use these
> patches…
>
 If you are under linux. Go through the root path of VTK and make :

patch -p0 < file.patch

On windows i don't know, it is to you to find an equivalent of linux patch
program.

> And there are a couple of questions in my mind. I am using wxWidgets mouse
> events instead of vtkRenderWindowInteractor for mouse interaction, and i
> must use these selections in mouse motion event too(for cursor change), can
> vtkVisibleCellSelection be fast as vtkPropPicker?
>
I don't know. make tests but I think it's the same speed (but if the
algorithm of vtkPropPicker is not the same, it can be faster than
vtkVisibleCellSelection).


> And how can I use it with backface culling?
>
Normally the backface culling is take in care on the pick selection and if
not it's a bug. What do you mean exactly ?

>
>
> *From:* Julian Ibarz [mailto:julian.ibarz at gmail.com]
> *Sent:* Thursday, July 24, 2008 12:20 PM
> *To:* Sercani
> *Subject:* Re: [vtkusers] vtkPropPicker tolerance?
>
>
>
> vtkPropPicker make picking using bounding box of your line so it's not what
> you need. You need a real picking and you can do that using
> vtkVisibleCellSelection but it is very slow.
>
> Personally I made two patches that increase the speed in some cases from 4
> to 10 times. You can find them at :
> http://www.vtk.org/Bug/view.php?id=7111
> http://www.vtk.org/Bug/view.php?id=7296
>
> This patches worked with 5-2 branch version of VTK. Not sure it works with
> nightly version but if not contact me i will update them.
>
> And example of use of this patches can be found here :
>
> The main idea is :
> Not recompile the scene after a picking (it permit to gain more that twice
> a time the picking). This is the first patch. Also draw only the objects
> pickable but visible (not removing the z-buffer, this is the second patch).
> This permits if you have a moment in your application that you can only
> select lines to render only them and gain more time.
>
> This patches was maded to improve selection of CAO models. In my program i
> can select faces, or edges or vertice but only one type at a time. So Imake
> pickable only faces, or edges or vertice. With none of this two patches for
> really big models (with 3 frame per seconds on rendering on my computer),
> the picking was about 5 or 6 seconds. Actually the picking is about 500 ms
> for faces and under 200 ms for edges...
>
> To make tolerance with vtkVisibleCellSelector make a window selection of
> 5x5 pixels for example. It will select your line if the line is on this
> window. You have my picking algorithm on the subversion of jCAE (
> http://jcae.sourceforge.net) :
> see file vtk-util/src/org/jcae/vtk/Scene.java on method Scene.pick.
>
> 2008/7/24 Sercani <sercanimailgroups at gmail.com>
>
> Hi everyone,
>
> I need vtkPropPicker for picking an actor which created from vtkLineSource.
> Other pickers are too slow and do not satisfy user requirements.
> vtkPropPicker is extremely fast but its tolerance is not enough,  picking
> the lines in a scene requires really good mouse skill and patience :D. I
> couldn't find a setTolerance function as such in vtkPicker… Is there another
> way to adjust picking tolerance in vtkPropPicker?
>
> Thanks already…
>
>
>
>
>
>
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>
>
> --
> Julian Ibarz
>



-- 
Julian Ibarz
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