[vtkusers] how to prevent glyph from turning black when data value used to scale is negative

[Allan James]

Hi Tracy,

I think the problem may be that the glyph IS actually being scaled by the negative value (rather than absolute). A result of this is that the surface normals are reversed and are therefore pointing inside the glyph. After the scale you could try to recalculate the surface normals so that they are always pointing outwards.

Hope this helps...

Cheers,

Allan James
High Performance Computing & Research Support
Queensland University of Technology
(07) 3138 9264
ar.james at qut.edu.au
http://www.qut.edu.au/its/hpc
 
><(((º>  ._.·´¯`·..  >++(((º>  ._.·´¯`·..  >++(((º>

-----Original Message-----


Message: 5
Date: Tue, 22 Sep 2009 15:22:21 -0700 (PDT)
From: Tracy Hu <tracy.hu at yahoo.com>
Subject: [vtkusers] how to prevent glyph from turning black when data
	value	used to scale is negative
To: vtkusers at vtk.org
Message-ID: <171276.13464.qm at web45107.mail.sp1.yahoo.com>
Content-Type: text/plain; charset="us-ascii"

I noticed that if you scale and color a sphere glyph with a single scalar array which value 
ranges from negative to positive, then sphere scales with absolute value, but become black 
when value is negative. Is there a way to tell it not to turn black, but color with values?

Thanks

Tracy