[vtkusers] VS: ÄvtkusersÅ Re: vtkusers digest, Vol 1 #2035 - 18 msgs

[Gerard Gorman]

Hämäläinen Janne wrote:
> Thanks for the answer, the Mayavi frontend seems interesting. Anyhow, I need
> to find the way to do the thing myself. We are developping our own software
> package, and I need to implement this feature to the existing software. I
> took only a quick glance at Mayavi, and I couldn't yet find where they blend
> volumes.
Well to answer your mayavi question, inside mayavi you can open 
multiable files at the same time, or indeed open multiable instances of 
the same file. So long as your coordinates are ok (or your origins are 
ok), the multiable objects will be displayed together (nicely blended 
etc). This is quite nice in mayavi because each object/file has its own 
visualization manager so you can operate on each object independantly 
from the rest which, when mixed with a bit of imagination, can yield 
some stunning effects. You might find a simular approach useful.

cheers
g



> 
> I'm still open for any suggestions on how to blend two volumes so that both
> would have different color (please, see my original message at the end of
> this message).
> 
> -Janne
> 
> 
> 
> 
>>----------
>>Lähettäjä: 	Dr. Daniel James White PhD[SMTP:dan at chalkie.org.uk]
>>Lähetetty: 	25. elokuuta 2003 17:05
>>Vastaanottaja: 	vtkusers at vtk.org
>>Aihe:  	ÄvtkusersÅ Re: vtkusers digest, Vol 1 #2035 - 18 msgs
>>
>>Hi Janne,
>>
>>try using the Mayavi VTK frontend, with the experimental volume module,
>>see the mayavi mailing list for this.
>>
>>Dan
>>
>>On Monday, August 25, 2003, at 04:52 PM, vtkusers-request at vtk.org wrote:
>>
>>
>>>Message: 2
>>>From: =?iso-8859-1?Q?H=E4m=E4l=E4inen_Janne?= <Janne.Hamalainen at hus.fi>
>>>To: "'vtkusers at vtk.org'" <vtkusers at vtk.org>
>>>Date: Mon, 25 Aug 2003 14:41:36 +0200
>>>Subject: [vtkusers] Blending two volumes
>>>
>>>Hi all,
>>>
>>>I have a following situation: I have two vtkImageData objects =
>>>(tomographic
>>>medical data) that I want to display using volume rendering. I would =
>>>want to
>>>blend them (as with vtkImageBlend), so that both objects would have
>>>different colors, e.g., so that I had a gray translucent data set and =
>>>inside
>>>that an opaque green area.=20
>>>
>>>I have done the same thing for 2D slices extracted from the volume by
>>>mapping the original intensity levels of the images to colors with
>>>vtkImageMapToColors (using a different vtkLookupTable for both) and
>>>combining the results with vtkImageBlend. The results can be shown =
>>>easily
>>>with 2D texture mapping. For 3D rendering this doesn't seem a possible 
>>>=
>>>way
>>>to do things. I can of course map the volumes to different colors and =
>>>blend
>>>them, but volume rendering seems to assume that the mapped data has no
>>>colors, but instead a vtkColorTransferFunction is used to map the =
>>>intensity
>>>levels. Different color transfers can be specified for each component =
>>>of the
>>>input data, but I don't understand how this is interpreted. Is it =
>>>simply
>>>that you can specify what component to use for volume rendering? And is
>>>there any way to use the original color components of the input =
>>>vtkImageData
>>>in volume rendering to get the desired effect?=20
>>>
>>>I also tried rendering (ray casting) the two volumes to a same scene =
>>>using a
>>>different color transfer for both, but the results weren't =
>>>satisfactory. The
>>>volume that was rendered last (it is inside the other volume) is not =
>>>veiled
>>>by the other translucent volume, but instead is shown as though it were
>>>outside it. The toggle IntermixIntersectingGeometry is on, although I =
>>>would
>>>guess that it hasn't any effect on volumes, right?
>>>
>>>If anyone 1. knows a way to volume render colored image data (or knows 
>>>=
>>>that
>>>it is not possible), or 2. knows if there is a way to render multiple
>>>volumes to a same scene so that overlapping parts are blended, I would
>>>gladly accept any information,
>>>
>>>-Janne
>>>
>>>
>>
>>Dr. Daniel James White BSc. (Hons.) PhD
>>Cell Biology
>>Department of biological and environmental science
>>PO Box  35
>>University of Jyväskylä
>>Jyväskylä FIN 40014
>>Finland
>>+358 (0)14 260 4183 (work)
>>+358 (0)414740463 (mob)
>>
>>http://www.chalkie.org.uk
>>dan at chalkie.org.uk
>>white at cc.jyu.fi
>>
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> 
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-- 
----------------------------------------------------------
Gerard Gorman (PhD Student)
Applied Modelling and Computation Group
Earth Science and Engineering
Imperial College
Prince Consort Road		Tel. 00 44 +207 594 9323
London SW7 2BP			Fax. 00 44 +207 594 9321
U.K.                    o~o A good slogan beats a good solution.
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