[vtkusers] WebGL 3D Viewer Demo

[Sebastien Jourdain]

Hi Sathish,

ParaViewWeb has been designed for remote rendering in order to achieve
interactive framerate on the client with collaborative session. In
that way, we extended it to support geometry delivery as well using
webgl technology. But because, it was in a dynamic context (dynamic
filter/dynamic output) we could not rely on a files and we had to make
sure that the client/server communication should stay at low as
possible.
Therefore, we defined a binary format that could be used 'as-is'
inside webgl. But as js/webgl has some limitation in array size, the
whole scene get split based on that maximum array size regarding which
array are needed to render it. Therefore, for large scene we end up
with a set of pieces that get loaded one after the other which allow
the user to see the scene to grow under their eyes.

But as you can see this rely on a dynamic mechanism which update the
client as soon as the data has changed on the server side. In case of
static data observation, the system is kind of overkill. So what we
did was to add an extra feature that allow the ParaViewWeb user to
export its scene as a single html file that embed the geometry pieces
and the webgl code that will render it inside the browser. Basically
you end up with a single HTML file that represent a 3D scene that
don't need any plugin to render and see it. And that's the links that
I've previously send. Those links are simple export of interactive
session done through ParaViewWeb.

And finally except for those static files, ParaViewWeb always deals
with runtime 3D data.
Regarding, the data size, they are pretty small as I remember, it's
basically the sample file given inside ParaView or VTK data. But
ParaViewWeb has been designed to handle much larger case as it could
rely on cluster to do the 3D processing if needed. Although, if you
are using the WebGL renderer, you will be limited by your web browser.

Seb

On Tue, Jan 10, 2012 at 3:06 AM, Sathish Kumar <kingvsk at aol.com> wrote:
> Hi Sebastien,
>
> Nice work. I am very much interested to get some feedback about your
> experience.
>
> Are you splitting the 3D data into multiple files?
> What is the size of 3D data file?
> Is the 3D constructed at runtime?
>
> Thanks,
> Sathish
>
>
>
> On Monday 09 January 2012 07:11 PM, Sébastien Valette wrote:
>
> Hi Sathish,
>
> interesting webpage! It's good to finally see webGL stuff reaching the VTK
> ecosystem! We also have developed something in our lab, see:
>
> http://www.creatis.insa-lyon.fr/~valette/epaule/
>
> it is a primitive simultaneous visualization of IRM slices and extracted
> parts of bones and lung. We've been doing this ourselves as there was no
> practical library to do that at that time.
>
> Greetings,
>
> Sebastien
>
>
> Le 06/01/2012 05:49, Sathish Kumar a écrit :
>
> One of the features planned for Oviyam-5 is to view 3D images from a DICOM
> series and without a plugin using WebGL. We've just taken the first steps
> towards reaching that goal.
>
> A technology preview with pre-rendered images is available at this link. Be
> patient while loading the 3D models, it may take few minutes to load.
>
> Technologies used: VTK, HTML5, WebGL, JSON, Javascript, JS-Unzip...
>
> Features:
> 1. Plugin-Free Design.
> 2. Supports all major modern browsers like Chrome, Firefox, Safari and
> Opera.(Use the latest versions available.The best performance is with Chrome
> and Firefox.
> 3. Supports IPhone, IPad and Android devices. However, due to the lack of
> memory, only the cube demo works at present
> 4. Load upto 36 MB of JSON 3D Data (Supports nearly 150 instances/slices).
> 5. Zoom In/Out Option.
> 6. Pan Option.
> 7. One click Axial, Coronal, Sagittal Views.
> 8. 2D Rotation.
> 9. 3D Rotation.
>
> Upcoming features:
> 1. Data Compression(Zip/Unzip) support for faster data transfer.
> 2. Support for Handheld devices.
> 3. Look-Up Table to get colour.
> 4. Support for user-defined models.
>
> Source:
> http://forums.dcm4che.org/jiveforums/thread.jspa?threadID=4233&tstart=0
>
> Regards,
> Sathish
>
>
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