[x3d-public] problem in nrrd example file header

[Andreas Plesch]

Don,

there is certainly no rush. It would be interesting to access the original
data files since some of the referenced files in the examples appear to
have been optimized and the source website www.volvis.org does not exist
anymore.

I will just continue to note issues in the examples.

For example, the use of lights in examples with styles which do not (appear
to?) use lighting such as opacitymap may be such a question although this
is probably more of a spec. question.

Andreas


On Jan 2, 2018 3:32 AM, "Don Brutzman" <brutzman at nps.edu> wrote:

Thanks for further checking Andreas.

Nicholas (cc:ed) is originator of these files.  Have also copied Medical
working group since these are relevant examples.

I will be happy to post updates to these files but am hoping that we all
proceed consistently to avoid versionitis later.  Further most are large
(indeed overwhelming usual .zip distributions) so it is good to get them
all sorted out correctly together.

v/r Don


On 1/1/2018 5:32 PM, Andreas Plesch wrote:

> It turns out that
>
> http://savage.nps.edu/Savage/VolumeRendering/datasets/nrrd/m
> ri_ventricles_segment.nrrd
>
> has the same problem of a malformed header line, eg. an excess space
> character in the spacings line.
>
> Here is a corrected nrrd file:
>
> https://cdn.glitch.com/405924cd-3c0d-476e-9b88-520a5610604c%
> 2Fmri_ventricles_segment_fixed.nrrd?1514854259949
>
> -Andreas
>
> On Mon, Dec 18, 2017 at 4:18 PM, Andreas Plesch <andreasplesch at gmail.com>
> wrote:
>
>> I am working on ImageTexture3D support for x3dom using the existing
>> ImageTextureAtlas node and https://github.com/scijs/nrrd-js as a
>> parser.
>>
>> It turns out the the parser is very strict, and so discovered a
>> malformed header line in
>> https://savage.nps.edu/Savage/VolumeRendering/datasets/nrrd/
>> mri_ventricles.nrrd
>> used in http://www.web3d.org/x3d/content/examples/Basic/VolumeRender
>> ing/BasicVentriclesIndex.html
>>
>> Specifically, the header line
>> 'spacings:  NaN 0.009 0.009 0.009'
>>
>> has _two_ space character after the colon delimiter. Exactly _one_
>> space is allowed, however, as described here:
>>
>> http://teem.sourceforge.net/nrrd/format.html#general.2
>> second paragraph:
>> ... a string "<field>" identifying the field (called the field
>> identifier), then a colon followed by a single space ": ", and then
>> the information describing the field "<desc>" (called the field
>> descriptor) ...
>>
>> The second space then acts as a separator making the first value in
>> the array an empty string which causes throwing when attempting to
>> parse as a float.
>>
>> I made an attempt at fixing the header by removing one space and made
>> the file available here:
>>
>> https://cdn.glitch.com/af228b45-6772-432d-a549-74f9f447b2c3%
>> 2Fmri_ventricles2.nrrd?1513631507711
>>
>> -Andreas
>>
>> --
>> Andreas Plesch
>> Waltham, MA 02453
>>
>
>
>
>

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman
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