[vtkusers] Problem with vtkActor->SetOrigin()
王君臣
wangjunchen at gmail.com
Wed May 26 09:13:59 EDT 2010
from the code snippet, I can't figure out why the translation happened in
your screenshot.
but I also tested the setorigin function, it indeed un-affected the original
position if no rotation and scale.
is it possible, something about m_actor happened anywhere alse ? Check it
carefully or debug it to trace the ComputerMatrix function of the actor.
2010/5/26 Anant Vemuri <ajar108 at gmail.com>
> Honestly, I am not doing much... Here is my buildPipeline() function. I
> load my transforms in another function. I know they are working properly,
> because the movement of the object is as predicted. However, I want to apply
> the transform with respect to a point different from the default origin so I
> want to use SetOrigin.
>
> There is one other thing. I am getting the polyData from another source. I
> make a copy of it in a member variable of my class m_polydata, and I use it
> to build my pipeline, I first run buildPipeline and when I actually load my
> object model I run updateMesh. But I believe this should not be a problem.
>
> void updateMesh( TriangularMesh::sptr mesh )
> {
> m_polyData = toVTKMesh(mesh);
> m_mapper->SetInput( m_polyData );
> this->setVtkPipelineModified();
> }
>
>
> //----------------------------------------------------------------------------------------------------------
>
> void TriangularMesh::buildPipeline( )
> {
> m_actor->GetProperty()->SetColor( m_color->red() , m_color->green() ,
> m_color->blue() );
>
> m_actor->SetMapper( m_mapper );
> if ( m_configuration->hasAttribute( "origin" ) )
> {
> m_actor->SetOrigin( -0.443477, -0.285047, 10.1173 );
> //m_actor->SetPosition( -4.43477, -2.85047, 101.173 );
> //m_defaultTrf->Translate( -4.43477, -2.85047, 101.173 );
> }
>
> if (m_scale>1)
> {
> m_actor->SetScale( m_scale, m_scale, m_scale ); /// This is the
> only other thing I dont know if it is affecting anything. But I turned this
> off to check, and got same result
> }
>
> if( !this->getTransformId().empty() ) /// I read the transform from a
> file, and check if it exists
>
> {
> m_defaultTrf->PostMultiply();
> m_defaultTrf->Concatenate( this->getTransform() );
> }
>
>
> //////////////////////////////////////////////////////////////////////////////////////////
> if ( m_configuration->hasAttribute( "concatTransform" ) ) /// In
> this particular case this is not being used. So this particular part is not
> executed.
> {
> std::string vtktrfID( m_configuration->getAttributeValue(
> "concatTransform" ) );
> vtkTransform *concatTrf = vtkTransform::New();
> concatTrf->SetInput( vtkTransform::SafeDownCast(
> this->getVtkObject( vtktrfID ) ) );
> concatTrf->Inverse();
> m_defaultTrf->Concatenate( concatTrf );
> }
>
> /// USER TRANSFORM
>
> m_actor->SetUserTransform( m_defaultTrf );
> this->setVtkPipelineModified();
> }
>
> Thank you for your help.
>
> Best regards,
> Anant.
>
>
> -----------
> Anant S. Vemuri
> email: ajar108 at gmail.com
>
>
>
> On Wed, May 26, 2010 at 7:17 PM, 王君臣 <wangjunchen at gmail.com> wrote:
>
>> it seems strange...
>> if you only set the origin by SetOrigin and keep others 0 or identity, it
>> should take no effect...
>> please notice the setposition, in your test, is it (0, 0, 0) ?
>> if everything is paid enough attention, could you please post your code
>> snippet?
>>
>>
>>
>> 2010/5/26 Anant Vemuri <ajar108 at gmail.com>
>>
>>> Thank you Wang. I went through the file and also the documentation. Here
>>> are the steps I did to test,
>>>
>>> 1. I applied nothing, no SetOrigin(), no SetUserTransform() and put my
>>> object in the scene. - image name = nothing_applied.jpg
>>> 2. The I apply SetOrigin(-0.443477, -0.285047, 10.1173), and no
>>> SetUserTransform() this gives me result shown in image =
>>> setOrigin_applied.jpg
>>>
>>> From what I read in your email and the documentation, this should not
>>> happen, right? Or am I interpreting it wrong. If not, then this is what is
>>> baffling me.
>>>
>>> Best regards,
>>> Anant.
>>>
>>>
>>> -----------
>>> Anant S. Vemuri
>>> email: ajar108 at gmail.com
>>>
>>>
>>>
>>> 2010/5/26 王君臣 <wangjunchen at gmail.com>
>>>
>>>
>>>> Hi, sorry for my uncompleted explanation. Now let's study the
>>>> underlying mechanism of "SetOrigin etc." together.
>>>> here is the source code of vtkProp3D::ComputeMatrix (vtk 5.4)
>>>>
>>>> void vtkProp3D::ComputeMatrix()
>>>> {
>>>> if (this->IsIdentity)
>>>> {
>>>> return;
>>>> }
>>>> // check whether or not need to rebuild the matrix
>>>> if ( this->GetMTime() > this->MatrixMTime )
>>>> {
>>>> this->GetOrientation();
>>>> this->Transform->Push();
>>>> this->Transform->Identity();
>>>> this->Transform->PostMultiply();
>>>> //* Notice This Code segment*
>>>> // begin {
>>>> // shift back to actor's origin
>>>> this->Transform->Translate(-this->Origin[0],
>>>> -this->Origin[1],
>>>> -this->Origin[2]);
>>>> // scale
>>>> this->Transform->Scale(this->Scale[0],
>>>> this->Scale[1],
>>>> this->Scale[2]);
>>>> // rotate
>>>> this->Transform->RotateY(this->Orientation[1]);
>>>> this->Transform->RotateX(this->Orientation[0]);
>>>> this->Transform->RotateZ(this->Orientation[2]);
>>>> // move back from origin and translate
>>>> this->Transform->Translate(this->Origin[0] + this->Position[0],
>>>> this->Origin[1] + this->Position[1],
>>>> this->Origin[2] + this->Position[2]);
>>>> //}end ==> it means: at first, the actor frame is an identity (same
>>>> with the world frame), then you have a chance to rotate or/and scale
>>>> the identity frame with respect to a point (specified by setorigin) in the
>>>> world frame. after that, the usermatrix takes efforts.
>>>> // apply user defined transform last if there is one
>>>> if (this->UserTransform)
>>>> {
>>>> this->Transform->Concatenate(this->UserTransform->GetMatrix());
>>>> }
>>>> this->Transform->PreMultiply();
>>>> this->Transform->GetMatrix(this->Matrix);
>>>> this->MatrixMTime.Modified();
>>>> this->Transform->Pop();
>>>> }
>>>> }
>>>> 2010/5/26 Anant Vemuri <ajar108 at gmail.com>
>>>>
>>>> Hi,
>>>>>
>>>>> I had posted a problem a few days back that I am still having with
>>>>> using vtkActor->SetOrigin(). The documentation of vtkProp3D says that
>>>>> SetOrigin(pos) function sets the point of rotation to the point specified by
>>>>> pos. However, when I apply SetOrigin(pos), my actor moves in the scene such
>>>>> that his point is at the world origin. For example, if I do SetOrigin(100,
>>>>> 100, 100), the actor moves such that the previous (100,100,100) is now at
>>>>> (0,0,0) initially before I apply any other transform to it. The effect is
>>>>> similar to when I do
>>>>>
>>>>> m_transform->Translate( -100,-100,-100 );
>>>>> m_actor->SetUserTransform( m_transform );
>>>>>
>>>>>
>>>>> Is this what is expected? Becase from the documentation, I understood
>>>>> that it should do translate(-newOrigin) [rotations, scaling etc]
>>>>> translate(newOrigin). Should I expect that when I do
>>>>> vtkActor->SetOrigin(newOrigin), the newOrigin moves to the world (0,0,0).
>>>>> Can someone explain this to me?
>>>>>
>>>>> Thank you.
>>>>> Anant.
>>>>>
>>>>>
>>>>> On Mon, May 24, 2010 at 11:27 PM, Anant Vemuri <ajar108 at gmail.com>wrote:
>>>>>
>>>>>> Thanks... But doesn't SetUserTransform() do that already... the vtk
>>>>>> documentation says as below...
>>>>>>
>>>>>> I think I understand the problem, but not sure how to correct it... I
>>>>>> am attaching a transform as the base transform which means that all
>>>>>> the other operations such as SetOrigin(), SetScale() get overridden.
>>>>>>
>>>>>>
>>>>>> On 5/24/10, 王君臣 <wangjunchen at gmail.com> wrote:
>>>>>> > what you need is a multiplication (PostMultiply) of m_defaultTrf to
>>>>>> the
>>>>>> > current actor transform not a replacement.
>>>>>> >
>>>>>> >
>>>>>> > 2010/5/24 Anant Vemuri <ajar108 at gmail.com>
>>>>>> >
>>>>>> >> Hi,
>>>>>> >>
>>>>>> >> I am trying to use myVtkActor->SetOrigin(origin) to set the origin
>>>>>> so that
>>>>>> >> any rotations I apply is done about this point. This is what I do
>>>>>> to build
>>>>>> >> the pipeline
>>>>>> >>
>>>>>> >>
>>>>>> >> void buildPipeline( )
>>>>>> >> {
>>>>>> >> m_actor->SetMapper( m_mapper );
>>>>>> >> m_actor->SetOrigin( 100, 100, 100 );
>>>>>> >> m_defaultTrf->Scale(m_scale, m_scale, m_scale);
>>>>>> >> m_defaultTrf->PostMultiply();
>>>>>> >> m_defaultTrf->Concatenate( this->getTransform() );
>>>>>> >> /// I add some more things to the m_defaultTrf
>>>>>> >> .
>>>>>> >> .
>>>>>> >> .
>>>>>> >> m_actor->SetUserTransform( m_defaultTrf );
>>>>>> >> }
>>>>>> >> std::cout << "\n\n\nOrigin = [" << m_actor->GetOrigin()[0] <<
>>>>>> ", " <<
>>>>>> >> m_actor->GetOrigin()[1] << ", " << m_actor->GetOrigin()[2] <<
>>>>>> "]\n\n\n";
>>>>>> >> }
>>>>>> >>
>>>>>> >> But when I apply the transform in the scene, it is not being about
>>>>>> some
>>>>>> >> other point entirely. I noticed that this is the same point when I
>>>>>> remove
>>>>>> >> the SetOrigin() line. But in the last line it gives me the origin
>>>>>> as the
>>>>>> >> one
>>>>>> >> that I set a few line earlier. I am not able to figure out what is
>>>>>> the
>>>>>> >> mistake. Can anyone help me?
>>>>>> >>
>>>>>> >> Thank you.
>>>>>> >> Anant.
>>>>>> >>
>>>>>> >> _______________________________________________
>>>>>> >> 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
>>>>>> >>
>>>>>> >> Follow this link to subscribe/unsubscribe:
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>>>>>> >>
>>>>>> >>
>>>>>> >
>>>>>> >
>>>>>> > --
>>>>>> >
>>>>>>
>>>>>>
>>>>>> --
>>>>>> -----------
>>>>>> Anant S. Vemuri
>>>>>> email: ajar108 at gmail.com
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> 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
>>>>>
>>>>> Follow this link to subscribe/unsubscribe:
>>>>> http://www.vtk.org/mailman/listinfo/vtkusers
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>>
>>>>
>>>
>>
>>
>> --
>> 人生就像一个刷牙缸，你可以认为它是杯具，也可以认为它是洗具
>>
>
>
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