[vtkusers] Possibly found a bug in vtkImplicitModeller.cxx

Roman Grothausmann roman.grothausmann at helmholtz-berlin.de
Wed Jul 11 12:59:52 EDT 2012 

On 11.07.2012 17:19, Bill Lorensen wrote:
> The * should remain.

But does that not lead to a MaximumDistance^4 in the actual calculation? 
At least that is the maximum value I find in the output if stored in 
32-bit real.

> The value of MaximumDistance is clamped between 0 and
> 1. You can set it to 1000000 if you want, but internally it will be set to
> 1.0.

I know, that's why  I changed 
vtkSetClampMacro(MaximumDistance,double,0.0,1.0);
to
vtkSetMacro(MaximumDistance,double);
(see patch below) and recompiled VTK. It works as I'd expect it, e.g. 
the maximum value I find in the output is very close to 10 if stored in 
32-bit real and using SetMaximumDistance(10).

-- VTK_orig/Hybrid/vtkImplicitModeller.cxx     2012-05-12 
13:59:27.000000000 +0200
+++ VTK/Hybrid/vtkImplicitModeller.cxx  2012-07-10 16:22:21.060066823 +0200
@@ -967,7 +967,7 @@
        }
      }

-  maxDist *= this->MaximumDistance;
+  maxDist = this->MaximumDistance;

    // Set volume origin and data spacing
    output->SetOrigin(this->ModelBounds[0],
--- VTK/Hybrid/vtkImplicitModeller.h    2012-05-12 13:59:27.000000000 +0200
+++ /home/grothama/sda8/programme/VTK/Hybrid/vtkImplicitModeller.h 
2012-07-11 16:27:36.203103443 +0200
@@ -119,7 +119,8 @@
    // Description:
    // Set / get the distance away from surface of input geometry to
    // sample. Smaller values make large increases in performance.
-  vtkSetClampMacro(MaximumDistance,double,0.0,1.0);
+  //vtkSetClampMacro(MaximumDistance,double,0.0,1.0);
+  vtkSetMacro(MaximumDistance,double);
    vtkGetMacro(MaximumDistance,double);

    // Description:

> On Wed, Jul 11, 2012 at 10:38 AM, Roman Grothausmann <
> roman.grothausmann at helmholtz-berlin.de> wrote:
>
>> Hello!
>>
>> It is clamped to be between 0 and 1 but in my tests does not behave as
>> being relative. If it were relative, it should surely not be squared.
>> Anyway, if You remove the '*' at line 967, the output contains only values
>> up to the absolute value specified with SetMaximumDistance.
>> To my understanding, the value stored in MaximumDistance is used as an
>> absolute value in the code and corresponds to the units of the input.
>> I just tested removing the clamping and allowing any double value yields
>> an output reaching up to 10 if SetMaximumDistance(10) is used.
>> If You agree, I'd therefore suggest not only to remove the '*' but also
>> the clamping in the header file.
>>
>> Thanks for Your comments on this
>> Roman
>>
>>
>>
>> On 11.07.2012 14:37, Jothybasu Selvaraj wrote:
>>
>>> If the bounds are (for simplicity) equal on all side of 5.0, then if I set
>>> the MaxDistacne to 0.2 ; how it will be aclculated?
>>>
>>> Will it be 0.5+ (0.5*0.2)=0.6?
>>>
>>> Thanks
>>>
>>> Jothy
>>>
>>>
>>>
>>> On Wed, Jul 11, 2012 at 1:35 PM, Bill Lorensen <bill.lorensen at gmail.com>*
>>> *wrote:
>>>
>>>   The bounds of the model, either computed or supplied.
>>>>
>>>>
>>>> On Wed, Jul 11, 2012 at 8:24 AM, Jothybasu Selvaraj <jothybasu at gmail.com
>>>>> wrote:
>>>>
>>>>   "MaximumDistance is a percentage"
>>>>>
>>>>>
>>>>> % of what?
>>>>>
>>>>> Jothy
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Jul 11, 2012 at 1:10 PM, Bill Lorensen <bill.lorensen at gmail.com
>>>>>> **wrote:
>>>>>
>>>>>   MaximumDistance is clamped to be within 0 and 1.
>>>>>>
>>>>>> On Wed, Jul 11, 2012 at 8:07 AM, Jothybasu Selvaraj <
>>>>>> jothybasu at gmail.com
>>>>>>
>>>>>>> wrote:
>>>>>>>
>>>>>>
>>>>>>   So, for instance what does 10.0 mean?
>>>>>>>
>>>>>>> Is it multiplication of the bounds of vtkPolyData?
>>>>>>>
>>>>>>> with bounds [-5,5,-5,5,-5,5] the operation will be applied in
>>>>>>> [-50,50,-50,50,-50,50]
>>>>>>>
>>>>>>> Thanks
>>>>>>>
>>>>>>> Jothy
>>>>>>>
>>>>>>> On Wed, Jul 11, 2012 at 1:03 PM, Bill Lorensen <
>>>>>>> bill.lorensen at gmail.com
>>>>>>>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>
>>>>>>>   MaximumDistance is a percentage, not an absolute distance. The
>>>>>>>> documentation is not clear about this.
>>>>>>>>
>>>>>>>>
>>>>>>>> On Wed, Jul 11, 2012 at 3:45 AM, Roman Grothausmann <
>>>>>>>> roman.grothausmann at helmholtz-**berlin.de<roman.grothausmann at helmholtz-berlin.de>>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>   Dear mailing list members,
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Could it be that in vtkImplicitModeller.cxx there is a bug that
>>>>>>>>> causes the maximum distance (that is calculated and saved in the
>>>>>>>>> image) to
>>>>>>>>> be bigger than specified with SetMaximumDistance()?
>>>>>>>>>
>>>>>>>>>   From the description of the filter and its parameters and also from
>>>>>>>>> the comments in the source I would expect that the output stored in
>>>>>>>>> 32-bit
>>>>>>>>> real does not contain values above SetMaximumDistance() except for
>>>>>>>>> the
>>>>>>>>> "background" value.
>>>>>>>>>
>>>>>>>>> Having checked the source it seems to me that the squared distance
>>>>>>>>> was always very carefully assigned to a variable name ending with 2
>>>>>>>>> (e.g.
>>>>>>>>> maxDistance2). However at line 967 there is a *= assignment (see
>>>>>>>>> patch
>>>>>>>>> below). Removing the '*', the output image of the filter then
>>>>>>>>> fulfils my
>>>>>>>>> expectations mentioned above.
>>>>>>>>>
>>>>>>>>> Could the '*' be a bug?
>>>>>>>>>
>>>>>>>>> --- VTK_orig/Hybrid/****vtkImplicitModeller.cxx     2012-05-12
>>>>>>>>> 13:59:27.000000000 +0200
>>>>>>>>> +++ VTK/Hybrid/****vtkImplicitModeller.cxx  2012-07-10
>>>>>>>>>
>>>>>>>>> 16:22:21.060066823 +0200
>>>>>>>>> @@ -967,7 +967,7 @@
>>>>>>>>>          }
>>>>>>>>>        }
>>>>>>>>>
>>>>>>>>> -  maxDist *= this->MaximumDistance;
>>>>>>>>> +  maxDist = this->MaximumDistance;
>>>>>>>>>
>>>>>>>>>      // Set volume origin and data spacing
>>>>>>>>>      output->SetOrigin(this->****ModelBounds[0],
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Happy coding
>>>>>>>>> Roman
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Dr. Roman Grothausmann
>>>>>>>>>
>>>>>>>>> Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
>>>>>>>>> Bereich Funktionale Materialien
>>>>>>>>> Institut für angewandte Materialforschung
>>>>>>>>> Hahn-Meitner-Platz 1
>>>>>>>>> D-14109 Berlin
>>>>>>>>>
>>>>>>>>> (früher Hahn-Meitner-Institut und BESSY)
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Tel.: +49-(0)30-8062-42816
>>>>>>>>> Fax.: +49-(0)30-8062-43059
>>>>>>>>>
>>>>>>>>> Vorsitzender des Aufsichtsrats: Prof. Dr. Dr. h.c. mult. Joachim
>>>>>>>>> Treusch
>>>>>>>>> Stellvertretende Vorsitzende: Dr. Beatrix Vierkorn-Rudolph
>>>>>>>>> Geschäftsführer: Prof. Dr. Anke Rita Kaysser-Pyzalla, Dr. Ulrich
>>>>>>>>> Breuer
>>>>>>>>> Sitz der Gesellschaft: Berlin
>>>>>>>>> Handelsregister: AG Charlottenburg, 89 HRB 5583
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> ______________________________****_________________
>>>>>>>>> Powered by www.kitware.com
>>>>>>>>>
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>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Please keep messages on-topic and check the VTK FAQ at:
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>>>>>>>>> http://www.vtk.org/Wiki/VTK_**FAQ <http://www.vtk.org/Wiki/VTK_FAQ>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
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>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Unpaid intern in BillsBasement at noware dot com
>>>>>>>>
>>>>>>>>
>>>>>>>> ______________________________**_________________
>>>>>>>> Powered by www.kitware.com
>>>>>>>>
>>>>>>>> Visit other Kitware open-source projects at
>>>>>>>> http://www.kitware.com/**opensource/opensource.html<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 <http://www.vtk.org/Wiki/VTK_FAQ>
>>>>>>>>
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>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Jothybasu Selvaraj
>>>>>>> PhD Student
>>>>>>> University of Liverpool
>>>>>>> UK
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> --
>>>>>> Unpaid intern in BillsBasement at noware dot com
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> Jothybasu Selvaraj
>>>>> PhD Student
>>>>> University of Liverpool
>>>>> UK
>>>>>
>>>>>
>>>>>
>>>>
>>>> --
>>>> Unpaid intern in BillsBasement at noware dot com
>>>>
>>>>
>>>>
>>>
>>>
>> --
>> Roman Grothausmann
>>
>> Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
>> Bereich Funktionale Materialien
>> Institut für angewandte Materialforschung
>> Hahn-Meitner-Platz 1
>> D-14109 Berlin
>>
>> (früher Hahn-Meitner-Institut und BESSY)
>>
>>
>> Tel.: +49-(0)30-8062-42816
>> Fax.: +49-(0)30-8062-43059
>>
>> Vorsitzender des Aufsichtsrats: Prof. Dr. Dr. h.c. mult. Joachim Treusch
>> Stellvertretende Vorsitzende: Dr. Beatrix Vierkorn-Rudolph
>> Geschäftsführer: Prof. Dr. Anke Rita Kaysser-Pyzalla, Dr. Ulrich Breuer
>> Sitz der Gesellschaft: Berlin
>> Handelsregister: AG Charlottenburg, 89 HRB 5583
>>
>>
>>
>>
>
>

-- 
Roman Grothausmann

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
Bereich Funktionale Materialien
Institut für angewandte Materialforschung
Hahn-Meitner-Platz 1
D-14109 Berlin	

(früher Hahn-Meitner-Institut und BESSY)


Tel.: +49-(0)30-8062-42816
Fax.: +49-(0)30-8062-43059

Vorsitzender des Aufsichtsrats: Prof. Dr. Dr. h.c. mult. Joachim Treusch
Stellvertretende Vorsitzende: Dr. Beatrix Vierkorn-Rudolph
Geschäftsführer: Prof. Dr. Anke Rita Kaysser-Pyzalla, Dr. Ulrich Breuer
Sitz der Gesellschaft: Berlin
Handelsregister: AG Charlottenburg, 89 HRB 5583

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