[vtkusers] Scaling glyphs[Scanned]

[John Platt]

Hi Jim,

 

Flattery will get you everywhere :-) but credit to John Biddiscombe -
vtkGlyph3D does just what it says on the tin!

 

John.

 

-----Original Message-----
From: James C Robinson [mailto:j.robinson at kepler-systems.com] 
Sent: 21 April 2005 17:15
To: 'John Platt'
Cc: Vtk Users
Subject: RE: [vtkusers] Scaling glyphs[Scanned]

 

John,

 

Many thanks for your reply. Your solution will work (I think). I have
made a crude test and it behaves as desired. The subtlety is that, when
one wants an application that allows the toggling between two
representations of a vector field (scaled according to magnitude or not)
the simple way is to turn SetScaleModeToDataScalingOff). However, this
leads to the behaviour that wanted to avoid (source points outside the
field being represented). Using your approach means effectively that we
leave the SetScaleModeToDataScalingOn and when we want an orientation
only representation we set the clamping range to be very tiny (say
SetRange(0.0,minimum value). In this way all 0.0 magnitude vectors are
not represented and any others are shown the same size.

 

I hope this clarifies the clarification further. Again many thanks. It
is not necessary to always no the answer, but it really helps to know a
man/woman who does..

 

Jim

 

James C Robinson, 

*    42 Rivergrove,

         Glanmire,

         Co. Cork,

         Eire

'     +353 21 4822028

         +353 87 2393010

*    jrobinson at eircom.net> 

  _____  

From: John Platt [mailto:jcplatt at lineone.net] 
Sent: 20 April 2005 20:56
To: j.robinson at kepler-systems.com
Cc: vtkusers at vtk.org
Subject: RE: [vtkusers] Scaling glyphs[Scanned]

 

Hi Jim,

 

Have you tried ClampingOn() with ScalingOn(). Data scales outside the
clamp range are reset to the range end points. The data scale is then
normalized to the range 0 - 1. All glyphs with a data scale less than
the lower clamp range are therefore mapped to zero. Provided data
scaling is on (SetScaleModeToDataScalingOn()), the composite scale
factor, DataScale*ScaleFactor will also be zero.

 

HTH

 

John.

 

-----Original Message-----
From: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] On
Behalf Of James C Robinson
Sent: 20 April 2005 13:46
To: Administrator
Cc: jcplatt at lineone.net
Subject: [vtkusers] Scaling glyphs[Scanned]

 

Dear all,

 

I am producing a set of glyphs using a vtkPlaneSource as the data
points. It works perfectly -  when I have scaling on, the glyphs behave
appropriately. However, when I turn scaling off (whowing vector
direction only) there are glyphs placed even at points (on the
vtkPlaneSource) that are outside the body (therefore magnitude is
implicitly zero).

 

I can Could anybody tell me if it is possible to have the glyphs
eliminated at points that are outside the field (or where the magnitude
is zero - or less than some threshold)?

 

Regards,

 

Jim

 

James C Robinson, 

*    42 Rivergrove,

         Glanmire,

         Co. Cork,

         Eire

'     +353 21 4822028

         +353 87 2393010

*    jrobinson at eircom.net> 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20050422/db5a5e2f/attachment.htm>