[vtkusers] Scaling and colouring glyphs withdifferent scalararrays

[John Platt]

Hi John,

Thanks for your offer - I am sure it will be much appreciated. If you
have ever used vtkTensorGlyph in anger, this suffers even more from
shortfalls in control over the scaling/colouring of the glyphs and in
particular, three glyphs.

It's a bit of a surprise to find that the glyph filters don't pass the
input attribute data. For maximum flexibility, it would be nice to be
able to control this aspect of behaviour which would provide a solution
for the colouring problem also. Any work done on vtkGlyph3D could then
be transferred to vtkTensorGlyph providing some uniformity in the
interface.

Sorry to complicate the issue but you might be able to kill two birds
with one stone.

John.
 
-----Original Message-----
From: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] On
Behalf Of John Biddiscombe
Sent: 04 April 2005 07:39
To: Paul Cochrane
Cc: John Platt; vtkusers at vtk.org
Subject: Re: [vtkusers] Scaling and colouring glyphs withdifferent
scalararrays


>and then call data.GetUnstructuredGridOutput(), I basically get back
exactly
>the grid that I put in.  It seems silly that I have several arrays in
the
>PointData section of the UnstructuredGrid object, each with names, but
which
>I can't specify one to use for sphere/glyph size, and one for colour.
I
>  
>

Part of the problem here is that there was some discussion on the 
developers list a while back about how the best way to set the scalars 
for a filter should be achieved. Many filters could be told to operate 
on either this scalar or that, and the question was - add this as a 
function at some lower level in the class heirarchy (ie back at the old 
vtkSource, or similar) level, or add it on a per filter basis depending 
on just what the filter is doing.

vtkGlyph3D is slightly unusual in that several SetXXbyName functions do 
exist, but the particular one you want isn't there. In this case, I'd 
suggest adding it to the bug tracker as a feature request for vtkGlyph3D

and I'll add in the ability to set scalar names for scaling and color 
independently. It's certainly something that is a fairly common request.

JB


-- 
John Biddiscombe,                            email:biddisco @ cscs.ch
http://www.cscs.ch/about/BJohn.php
CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
Via Cantonale, 6928 Manno, Switzerland      | Fax:  +41 (91) 610.82.82

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