[vtkusers] Noise appears when extreme zooming in
Ken Martin
ken.martin at kitware.com
Tue Oct 25 10:18:15 EDT 2016
You can add some code to check the actor bounds against the camera
position. In it's simplest form you could do something like
if (vtkMath:Distance(actor->GetCenter, camera->GetPosition) <
actor->GetLength())
{
camera->SetPosition(cam->GetFocalPoint() -
camera->DirectionOfProjection*actor->GetLength()*1.1)
}
Lots of syntax issues above, but that is the idea.
On Wed, Oct 19, 2016 at 3:27 PM, Patricio Palma C. <patriciop at gmail.com>
wrote:
> With vtkInteractorStyleRubberBandZoom::Zoom() I'm having good results,
> no noise when getting closer to the structure. However it is easy to go
> into the structure. Does VTK provides a way to avoid the camera go into the
> visible object?
>
> Thanks
>
>
> On Tue, Oct 18, 2016 at 3:06 PM, Ken Martin <ken.martin at kitware.com>
> wrote:
>
>> OK in that case you want to print out the ViewAngle of the camera. It
>> could be that the view angle is getting really small leading to some
>> issues.
>> It might be worth trying to use Dolly instead of Zoom. The difference is
>> that Zoom adjust the view angle while Dolly moves the position.
>>
>> On Tue, Oct 18, 2016 at 1:24 PM, Patricio Palma C. <patriciop at gmail.com>
>> wrote:
>>
>>> Hi Ken, experts
>>>
>>> I have double checked and the case shown in previous email, do not have
>>> coincident geometries.
>>>
>>> Regarding the interactor, I'm using a custom interactor style (derived
>>> from vtkInteractorStyle) that provides a rubber band zoom into the 3D
>>> scene. The code shows Dolly() function in custom interactor is calling
>>> camera->Zoom().
>>>
>>> Regards
>>> Patricio
>>>
>>>
>>> On Tue, Oct 18, 2016 at 9:49 AM, Ken Martin <ken.martin at kitware.com>
>>> wrote:
>>>
>>>> Are you zooming using one of VTK's interactor styles? or are you
>>>> explicitly calling zoom or dolly on the camera? Using dolly() the distance
>>>> on the camera should be changing and as you noticed it isn't.
>>>>
>>>> Since you mentioned you have coincident geometry that can be an issue.
>>>> When you have two polygons at the same location the rendering process can
>>>> result in a random determination of which is on top. If the coincident
>>>> geometry is in two different mappers you can use the
>>>>
>>>> void SetRelativeCoincidentTopologyPolygonOffsetParameters(
>>>> double factor, double units);
>>>>
>>>> method to move one of the mappers slightly in front of the other.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Oct 18, 2016 at 1:01 AM, Patricio Palma C. <patriciop at gmail.com
>>>> > wrote:
>>>>
>>>>> Hi Ken, experts,
>>>>>
>>>>> Thank you for the quick response.
>>>>> Regarding point one, SetDiffuse(0.0) was applied to all actors, the
>>>>> structure looks darker with no shadows, but the issue still occurs.
>>>>>
>>>>> About point 2:
>>>>> - the actor we use is derived from vtkQuadricLODActor
>>>>> - and there are some overlapping geometries
>>>>>
>>>>> Below is a image of the structure in the beginning. Clipping range,
>>>>> position, focal point and distance are shown below
>>>>> [image: Inline image 1]
>>>>> Debug: Camera clipping range: 3.61282 4.44839
>>>>> Debug: Camera position: -1.93487 2.37646 2.48559
>>>>> Debug: Camera focal point: 0.0543755 -0.0598546 0.0492757
>>>>> Debug: Camera distance: 3.97849
>>>>> Debug: Bounds : [ -0.100974 , 0.296875 , -0.08 ] [ 0.08 , 0
>>>>> , 0.05 ]
>>>>>
>>>>> After zooming in a bit, it appears a soft pattern of lines over the
>>>>> face of the structure
>>>>> [image: Inline image 2]
>>>>> Debug: Camera clipping range: 3.61282 4.44839
>>>>> Debug: Camera position: -1.92875 2.37186 2.4952
>>>>> Debug: Camera focal point: 0.0604954 -0.0644594 0.0588774
>>>>> Debug: Camera distance: 3.97849
>>>>> Debug: Bounds : [ -0.100974 , 0.296875 , -0.08 ] [ 0.08 , 0
>>>>> , 0.05 ]
>>>>>
>>>>> Finally after zooming in a couple of steps more, it appears
>>>>> noise/lines over the face.
>>>>> [image: Inline image 3]
>>>>> Debug: Camera clipping range: 3.61282 4.44839
>>>>> Debug: Camera position: -1.92882 2.37202 2.49498
>>>>> Debug: Camera focal point: 0.0604254 -0.0643013 0.0586621
>>>>> Debug: Camera distance: 3.97849
>>>>> Debug: Bounds : [ -0.100974 , 0.296875 , -0.08 ] [ 0.08 , 0
>>>>> , 0.05 ]
>>>>>
>>>>> It calls my attention that only position and focal point are being
>>>>> updated after zooming in.
>>>>>
>>>>> Thanks
>>>>> Patricio
>>>>>
>>>>> On Mon, Oct 17, 2016 at 8:21 PM, Ken Martin <ken.martin at kitware.com>
>>>>> wrote:
>>>>>
>>>>>> It could be a few things, we would really need more details to narrow
>>>>>> it down. Two things you can check
>>>>>>
>>>>>> 1) maybe a lighting issue, if you change your actors to be only
>>>>>> ambient, no diffuse, do you still see the issue?
>>>>>>
>>>>>> 2) maybe a zbuffer issue, If you zoom too far you can end up with bad
>>>>>> (not ideal) zbuffer clipping ranges. To narrow that down
>>>>>> - are these Actors or Actor2D, what mapper are you using,
>>>>>>
>>>>>> do you have overlapping or coincident geometry?
>>>>>> - when you see the problem what is the value of
>>>>>>
>>>>>> - the camera's clipping range
>>>>>> - camera's position, and focal point, distance
>>>>>> - the bounds of your data
>>>>>>
>>>>>> Generally you do not want any of those values to be really small or
>>>>>> large relative to the square root of the range a float can normally hold.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Oct 17, 2016 at 5:28 PM, Patricio Palma C. <
>>>>>> patriciop at gmail.com> wrote:
>>>>>>
>>>>>>> Hi experts, does anybody has any idea of what could causing the
>>>>>>> issue described in the previous email?
>>>>>>> Recently I have noted that something similar occurs on 3D
>>>>>>> structures when zooming in extremely to the structure and then rotating it.
>>>>>>> It appears a kind of pattern to generate the shadow of the face but as you
>>>>>>> rotate the structure the face begin to get noisy.
>>>>>>>
>>>>>>> My current setup is VTK git development branch using OpenGL2 as
>>>>>>> rendering backend. mesa 12.0.1 with AVX. I have also tried using mesa 11.2
>>>>>>> and the results are the same.
>>>>>>>
>>>>>>> Thanks!
>>>>>>> Regards
>>>>>>> Patricio
>>>>>>>
>>>>>>> El Monday, October 3, 2016, Patricio Palma C. <patriciop at gmail.com>
>>>>>>> escribió:
>>>>>>>
>>>>>>>> Dear Experts
>>>>>>>>
>>>>>>>> I'm using VTK 7.1 (latest Git version) and Mesa 12.0 with AVX. I
>>>>>>>> have an application that display a 2D structure and some data on it. After
>>>>>>>> zooming in a couple times in the same spot of the structure it begins to
>>>>>>>> appear some noise over the 2D structure that increase after continuing
>>>>>>>> zooming in.
>>>>>>>>
>>>>>>>> Is this a known issue? is there a way to solve/avoid this?
>>>>>>>>
>>>>>>>> I've attached some pictures showing how the noise appears while
>>>>>>>> zooming in.
>>>>>>>>
>>>>>>>> [image: Inline image 2]
>>>>>>>> [image: Inline image 3]
>>>>>>>> [image: Inline image 5]
>>>>>>>> [image: Inline image 6]
>>>>>>>>
>>>>>>>> --
>>>>>>>> Patricio Palma Contreras
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Patricio Palma Contreras
>>>>>>>
>>>>>>>
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>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Ken Martin PhD
>>>>>> Chairman & CFO
>>>>>> Kitware Inc.
>>>>>> 28 Corporate Drive
>>>>>> Clifton Park NY 12065
>>>>>> 518 371 3971
>>>>>>
>>>>>> This communication, including all attachments, contains confidential
>>>>>> and legally privileged information, and it is intended only for the use of
>>>>>> the addressee. Access to this email by anyone else is unauthorized. If you
>>>>>> are not the intended recipient, any disclosure, copying, distribution or
>>>>>> any action taken in reliance on it is prohibited and may be unlawful. If
>>>>>> you received this communication in error please notify us immediately and
>>>>>> destroy the original message. Thank you.
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Patricio Palma Contreras
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Ken Martin PhD
>>>> Chairman & CFO
>>>> Kitware Inc.
>>>> 28 Corporate Drive
>>>> Clifton Park NY 12065
>>>> 518 371 3971
>>>>
>>>> This communication, including all attachments, contains confidential
>>>> and legally privileged information, and it is intended only for the use of
>>>> the addressee. Access to this email by anyone else is unauthorized. If you
>>>> are not the intended recipient, any disclosure, copying, distribution or
>>>> any action taken in reliance on it is prohibited and may be unlawful. If
>>>> you received this communication in error please notify us immediately and
>>>> destroy the original message. Thank you.
>>>>
>>>
>>>
>>>
>>> --
>>> Patricio Palma Contreras
>>>
>>
>>
>>
>> --
>> Ken Martin PhD
>> Chairman & CFO
>> Kitware Inc.
>> 28 Corporate Drive
>> Clifton Park NY 12065
>> 518 371 3971
>>
>> This communication, including all attachments, contains confidential and
>> legally privileged information, and it is intended only for the use of the
>> addressee. Access to this email by anyone else is unauthorized. If you are
>> not the intended recipient, any disclosure, copying, distribution or any
>> action taken in reliance on it is prohibited and may be unlawful. If you
>> received this communication in error please notify us immediately and
>> destroy the original message. Thank you.
>>
>
>
>
> --
> Patricio Palma Contreras
>
--
Ken Martin PhD
Chairman & CFO
Kitware Inc.
28 Corporate Drive
Clifton Park NY 12065
518 371 3971
This communication, including all attachments, contains confidential and
legally privileged information, and it is intended only for the use of the
addressee. Access to this email by anyone else is unauthorized. If you are
not the intended recipient, any disclosure, copying, distribution or any
action taken in reliance on it is prohibited and may be unlawful. If you
received this communication in error please notify us immediately and
destroy the original message. Thank you.
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