[vtkusers] Color of isosurface

[Bill Lorensen]

I'll bet your normals are point "in" rather than "out".  Try vtkReverSense
on the output of your isosurface.

On Mon, Jul 2, 2012 at 2:37 PM, Dale "Luke" Peterson <hazelnusse at gmail.com>
wrote:
> I tried ScalarVisibilityOff() and it didn't fix the problem.  However,
> it did make me realize that the problem is different from what I
> originally thought.  I've attached two window screen shots, both with
> ScalarVisibilityOff().  The only difference is that in the second one,
> I've called contourActor->GetProperty()->SetColor(0, 0, 1).  You can
> see that the blue color is just barely visible.
>
> Just to check, I tried setting ScalarVisibilityOn(), and then repeated
> the test with and without calling SetColor(0, 0, 1).  In both cases
> the surface appears to be very dark but slightly red.  So it seems
> like red is the default color for the zero-level curve, but for some
> reason, my surface is showing a whole lot darker than I would like.
>
> Thanks for suggestion and let me know if you have any other ideas.
>
> Thanks,
> ~Luke
>
>
> On Mon, Jul 2, 2012 at 10:51 AM, Jothy <jothybasu at gmail.com> wrote:
>> Can you try contourMapper->setScalarVisibilityOff()
>>
>> Jothy
>>
>> On 02-Jul-2012, at 5:52 PM, "Dale \"Luke\" Peterson" <
hazelnusse at gmail.com> wrote:
>>
>>> I subclassed vtkImplicit function and implemented EvaluateFunction()
>>> and EvaluateGradient().  I then use vtkSampleFunction,
>>> vtkContourFilter, vtkPolyDataMapper, and vtkActor and add the actor to
>>> a renderer.  I am only interested in one iso-surface, the zero
>>> iso-surface, and in the past it always displayed in red.  Something
>>> changed (likely in my code) but I can't figure out what, and the the
>>> surface renders only in black.  I have tried calling
>>> GetProperty()->SetColor() on the actor but this has no effect.  I also
>>> tried dropping in example code for the vtkSphereSource which shows up
>>> blue, as in the tutorial.  Based on this, I'm guessing that there is
>>> something going on with vtkSampleFunction, vtkContourFilter, or
>>> vtkPolyDataMapper, but I can't figure out what.
>>>
>>> I am doing all of this in my own subclassed QVTKWidget, and the color
>>> used to work fine.  I also have a minimal example of the surface that
>>> doesn't use QVTKWidget and it shows the surface in red.  Perhaps there
>>> is something strange going on in Qt?
>>>
>>> Any ideas on what might be going on?
>>>
>>> The relevant code I have in the constructor of my QVTKWidget subclass
is:
>>>
>>>  configurationSurface = vtkSmartPointer<vtkHolonomicConstraint>::New();
>>>  sample = vtkSmartPointer<vtkSampleFunction>::New();
>>>  sample->SetSampleDimensions(50, 50, 50);
>>>  sample->SetImplicitFunction(configurationSurface);
>>>  // Create the 0 isosurface
>>>  contour = vtkSmartPointer<vtkContourFilter>::New();
>>>  contour->SetInputConnection(sample->GetOutputPort());
>>>  contour->GenerateValues(1, 0.0, 0.0);
>>>  contour->Update();
>>>
>>>  // Map the contours to graphical primitives
>>>  contourMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
>>>  contourMapper->SetInputConnection(contour->GetOutputPort());
>>>
>>>  // Create an actor for the contours
>>>  contourActor = vtkActor::New();
>>>  contourActor->SetMapper(contourMapper);
>>>
>>>  // Has no effect: still shows up as black.
>>>  contourActor->GetProperty()->SetColor(0,0,1);
>>>
>>> Thanks,
>>> Luke
>>>
>>>
>>> --
>>> "People call me a perfectionist, but I'm not. I'm a rightist. I do
>>> something until it's right, and then I move on to the next thing."
>>> -- James Cameron
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>
>
>
> --
> "People call me a perfectionist, but I'm not. I'm a rightist. I do
> something until it's right, and then I move on to the next thing."
> -- James Cameron
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
http://www.vtk.org/Wiki/VTK_FAQ
>
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