[Paraview] 3D contour smoothness

Mon Oct 13 07:51:26 EDT 2014

Philipp,

Great, I'm glad to hear it is working again as you expect.

- Cory

On Mon, Oct 13, 2014 at 3:17 AM, Philipp E <pspeachum at gmail.com> wrote:
> Hi Cory,
>
> you are correct. This tiny change solves the problem! I hope that our
> discussion will also allow others to review their output code with
> respect to this change.
>
> Thank you very much for clarification and your help (and your great
> software as well).
>
> Best regards
> Philipp Engels
>
> On 10/10/2014 07:20 PM, Cory Quammen wrote:
>> Hi Philipp,
>>
>> I looked into this more, and it turns out it isn't a bug, but a new
>> feature in ParaView/VTK that lets provides more flexibility in the
>> numeric type of the point positions. By default, most filters will set
>> the numeric type of the output points to the numeric type of their
>> inputs. In the data set you sent me, the points are set to have type
>> int (specified on line 7), which means that the points in the output
>> of the Contour filter will be cast to ints. This explains the jagged
>> appearance of your surfaces.
>>
>> The change in VTK that brings about this behavior is:
>>
>> commit f830ef4cd79b1e7c8af2fae6ed1dd02ffa2cd670
>> Author: Paul Edwards <Paul.Edwards3 at Rolls-Royce.com>
>> Date:   Thu Jan 10 10:01:47 2013 -0500
>>
>>     Fixing loss of point-precision in certain filters.
>>
>>     Certain filters tend to loose point precision and end up
>> converting double point
>>     arrays to flot arrays. This patch address the issue for a few
>> filters using the
>>     API added to vtkAlgorithm by commit 49d1f124.
>>
>>     Change-Id: I8740e4e4bfdd9944fbadb45744038e42eff04830
>>
>> Now, how to fix your problem? If you change the type of points from
>> int to double in your data file so that it reads
>>
>> POINTS 6823544 double
>>
>> instead of
>>
>> POINTS 6823544 int
>>
>> all should work as expected.
>>
>> Please let me know if that doesn't solve the problem for you.
>>
>> Best regards,
>> Cory
>>
>> On Wed, Oct 8, 2014 at 7:47 AM, Cory Quammen <cory.quammen at kitware.com> wrote:
>>> Philipp,
>>>
>>> I apologize, but I haven't had time to look more into this problem.
>>> I'll have another look soon.
>>>
>>> Thanks,
>>> Cory
>>>
>>> On Wed, Oct 8, 2014 at 3:11 AM, Philipp E <pspeachum at gmail.com> wrote:
>>>> Hi Cory,
>>>>
>>>> can you report any updates for this issue?
>>>>
>>>> Best regards and thanks for your efforts
>>>> Philipp
>>>>
>>>> On 09/19/2014 07:17 PM, Cory Quammen wrote:
>>>>> Just a little more info on this. The problem starts with 3.98.
>>>>>
>>>>> On Fri, Sep 19, 2014 at 12:08 PM, Philipp E. <pspeachum at gmail.com> wrote:
>>>>>> Sorry Cory,
>>>>>>
>>>>>> you are right. The cell number is the same.
>>>>>>
>>>>>> Regards
>>>>>> Philipp
>>>>>>
>>>>>>
>>>>>> Am 19.09.2014 um 17:46 schrieb Cory Quammen:
>>>>>>> Philipp,
>>>>>>>
>>>>>>> I can confirm what you see with a pre 4.2 version of ParaView.
>>>>>>> However, the number of produced cells is the same.
>>>>>>>
>>>>>>> I will try to track down why this changed.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Cory
>>>>>>>
>>>>>>> On Fri, Sep 19, 2014 at 11:17 AM, Philipp E <pspeachum at gmail.com> wrote:
>>>>>>>> Hi Cory
>>>>>>>>
>>>>>>>> I managed to compress the data set to a fair size and attached it to
>>>>>>>> this mail. The data set is pressure, contour value is 0.55.
>>>>>>>>
>>>>>>>> By looking again at the data (contour -> information), I just found that
>>>>>>>> the old version (3.14.1) uses 148432 cells , while the the new one
>>>>>>>> employs 75232 cells. Hope that helps.
>>>>>>>>
>>>>>>>> Kind regards
>>>>>>>> Philipp
>>>>>>>>
>>>>>>>> Errata: I meant 4.2.0RC1 in the previous mails.
>>>>>>>>
>>>>>>>> On 09/19/2014 04:59 PM, Cory Quammen wrote:
>>>>>>>>> Phillipp,
>>>>>>>>>
>>>>>>>>> Do you have a data set similar to the one you've shown that you can share?
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Cory
>>>>>>>>>
>>>>>>>>> On Fri, Sep 19, 2014 at 10:48 AM, Philipp E <pspeachum at gmail.com> wrote:
>>>>>>>>>> Hi Cory,
>>>>>>>>>>
>>>>>>>>>> thank you for your fast feedback.
>>>>>>>>>>
>>>>>>>>>> a) Compute normal is checked. (Without normals, the contour is
>>>>>>>>>> completely stepped)
>>>>>>>>>> b) Contour values are the same.
>>>>>>>>>>
>>>>>>>>>> Regards
>>>>>>>>>> Philipp
>>>>>>>>>>
>>>>>>>>>> On 09/19/2014 04:40 PM, Cory Quammen wrote:
>>>>>>>>>>> Philipp,
>>>>>>>>>>>
>>>>>>>>>>> In the contour filter, is the option "Compute Normals" checked in 4.0 RC1?
>>>>>>>>>>>
>>>>>>>>>>> Also, are the contour values the same between the two versions?
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Cory
>>>>>>>>>>>
>>>>>>>>>>> On Fri, Sep 19, 2014 at 10:25 AM, Philipp E <pspeachum at gmail.com> wrote:
>>>>>>>>>>>> Hello everyone,
>>>>>>>>>>>>
>>>>>>>>>>>> after extensive search I was desperate enough to post on this list:
>>>>>>>>>>>>
>>>>>>>>>>>> It appears that the surface smoothing algorithm of the contour filter
>>>>>>>>>>>> does not work as "aggressive" as in older version (3.14.1 was the last
>>>>>>>>>>>> one we found to do so). As an example I prepared this two screenshots,
>>>>>>>>>>>> VTK data are scalars on a structured grid (200x100x100), legacy format.
>>>>>>>>>>>> (An additional call of the "smooth" filter does not help.)
>>>>>>>>>>>>
>>>>>>>>>>>> 3.14.1
>>>>>>>>>>>> http://s7.directupload.net/images/140919/euadfvko.png
>>>>>>>>>>>> 4.0.RC1
>>>>>>>>>>>> http://s14.directupload.net/images/140919/84y689mi.png
>>>>>>>>>>>>
>>>>>>>>>>>> Both versions are running with the shipped settings. Since the effect
>>>>>>>>>>>> could be reproduced on several workstations, we are wondering whether
>>>>>>>>>>>> there has been an (undocumented?) change in the filter mechanism or some
>>>>>>>>>>>> option we/setting/data problem we are not aware of.
>>>>>>>>>>>>
>>>>>>>>>>>> Kind regards and thanks in advance
>>>>>>>>>>>> Philipp Engels.
>>>>>>>>>>>>
>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>> 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 ParaView Wiki at: http://paraview.org/Wiki/ParaView
>>>>>>>>>>>>
>>>>>>>>>>>> Follow this link to subscribe/unsubscribe:
>>>>>>>>>>>> http://public.kitware.com/mailman/listinfo/paraview
>