[vtkusers] Re: Picking problems

[Mark Gooding]

Hello vtkers,

After a little further investigation of the proble (see below). I have
discovered that my code only crashes if I have both pickable
vtkImageActors and pickable vtkActors in the rendered scene. If I have
only one or the other but not both everything works fine. Whilst I'm
loathed to suggest that there is a bug in vtk, I'm not sure how what I
have done could cause the problem.

Fortunately I seem to be able to get around the problem by using
PickableOff() on my vtkImageActors, which suits me as I don't want my
users picking the imageActors anyway.

Thought I should post so it's there in the archives should anyone else
have the same problem, or someone feels like a further
investigation....

talking of the archives - I wasn't having much luck searching them
today. I was getting no results for "vtkActors" ! I suspect there is a
problem there.

Cheers,

Mark

On 9/28/06, Mark Gooding <mark.gooding at gmail.com> wrote:
>
> 1.) I'm getting an access violations when using the standard "p" to
> pick object. Everything works fine when I am only displaying
> vtkImageActors, but it crashes when I am trying to pick vtkActors
> derived using from images using thresholds & fast marching etc. The
> crash doesn't occur consistently, in that I can sometimes pick the
> actor, but sometime get a crash immediately. Repeatedly picking at the
> same point will cause the crash to occur eventually, normally occuring
> within a couple of pick actions.
>
> The access violation generally occurs in
> vtkAssemblyPath::GetLastNode() when doing "return (vtkAssemblyNode
> *)(this->Bottom->Item);", although sometimes it occurs in
> vtkRenderer::PickGeometry() when doing "prop =
> this->PathArray[i]->GetLastNode()->GetViewProp();".
>
> I'm guessing it is something that I've done wrong, since nobody appear
> to have reported this problem before (although it sounds similar to
> Anja Ende's point picking question from the beginning of the month).
> But I have no idea where to begin trying to solve this problem, since
> the error is occuring within the vtk code rather than in my code (I
> almost know what my own code does, but the inner workings of vtk are
> magic!!). Any suggestions/help would be very welcome.