[IGSTK-Users] EllipsoidObject Radius

[Patrick Cheng]

Hi Jake,

You are right. The problem is that the default "Size" of the
m_EllipsoidSource is 0.5

We need to set it to be 1, if we consider the scale factors to be radius 
not diameter.

The fix should be:
m_EllipsoidSource->SetSize( 1.0 );
m_EllipsoidSource->SetScale( radius[0], radius[1], radius[2] );

Thank you for reporting this.

Patrick

Jake McIvor wrote:
> I think I found it:
> 
> In the UpdateRepresentationProcessing and SetEllipsoidObjectProcessing
> methods, the scale of the vtkSuperquadricSource is updated:
> 
>  EllipsoidObjectType::ArrayType radius = m_EllipsoidObject->GetRadius();
>     m_EllipsoidSource->SetScale( radius[0], radius[1], radius[2] );
> 
> The second line should read:
>    m_EllipsoidSource->SetScale( 2*radius[0], 2*radius[1], 2*radius[2] );
> 
> Does that make sense, or am I confusing the use of the setRadius method?
> 
> -Jake
> 
> 
> On Thu, Jul 23, 2009 at 11:43 AM, Jake
> McIvor<jdmcivor at interchange.ubc.ca> wrote:
>> I believe there is a bug somewhere in the ellipsoidObject or
>> ellipsoidObjectRepresentation classes.  When I use the SetRadius
>> method, the resulting ellipsoid's axes are half as big as they should
>> be ( i.e. the length of each axis is set to the radius, instead of
>> each radius being half the legth of the axis.)
>>
>> My application uses the QtWidget.  Here is a code snippet that should
>> display two 10mm spheres, touching at one point.
>>
>> // test ellipsoid radii
>>
>>       igstk::EllipsoidObject::Pointer sphere1 = igstk::EllipsoidObject::New();
>>       sphere1->SetRadius( 10,10,10 );
>>
>>       igstk::EllipsoidObjectRepresentation::Pointer sphere1rep =
>>            igstk::EllipsoidObjectRepresentation::New();
>>       sphere1rep->RequestSetEllipsoidObject( sphere1 );
>>       sphere1rep->SetColor( 1.0,0.0,0.0 );
>>       sphere1rep->SetOpacity( 0.9 );
>>
>>       igstk::EllipsoidObject::Pointer sphere2 = igstk::EllipsoidObject::New();
>>       sphere2->SetRadius(10,10,10);
>>
>>       igstk::EllipsoidObjectRepresentation::Pointer sphere2rep =
>>           igstk::EllipsoidObjectRepresentation::New();
>>       sphere2rep->RequestSetEllipsoidObject( sphere2 );
>>       sphere2rep->SetColor( 0.0,0.0,1.0 );
>>       sphere2rep->SetOpacity( 0.9 );
>>
>>       igstk::Transform identity;
>>       identity.SetToIdentity(igstk::TimeStamp::GetLongestPossibleTime());
>>       igstk::Transform transform;
>>       igstk::Transform::VectorType translation;
>>       igstk::Transform::VersorType rotation;
>>       translation[0] = 20.0;
>>       translation[1] = 0.0;
>>       translation[2] = 0.0;
>>       rotation.Set( 0.0, 0.0, 0.0, 1.0 );
>>       igstk::Transform::ErrorType errorValue = 0;
>>
>>       transform.SetTranslationAndRotation(
>>           translation, rotation, errorValue,
>>           igstk::TimeStamp::GetLongestPossibleTime() );
>>
>>       sphere1->RequestSetTransformAndParent( identity, m_View );
>>       sphere2->RequestSetTransformAndParent( transform, m_View );
>>
>>       m_View->RequestAddObject( sphere1rep );
>>       m_View->RequestAddObject( sphere2rep );
>>
>>
>> Cheers,
>>
>> Jake
>>
>> --
>> Jake McIvor
>> MASc Candidate, Biomedical Engineering
>> Univerisity of British Columbia
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