[vtkusers] Color of isosurface

[Dale "Luke" Peterson]

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
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