[vtkusers] Black lines?

John Norris jnorris at mcs.anl.gov
Fri Oct 18 11:27:41 EDT 2002


I'm using VTK4.0, so if some of these things have been addressed in 4.1,
please forgive me.

I'm using vtkTensorGlyph with a vtkAxes as the source (with symmetry turned
on), and I've run into a few problems.

First, the output of vtkTensorGlyph eventually is run through
vtkPolyDataNormals (the glyph is often a sphere or cone, and the output may
be clipped, capped and triangulated, and I have to use vtkPolyDataNormals to
avoid some strange lighting effects at sharp corners).  When I'm using vtkAxes
as the glyph, however, vtkPolyDataNormals panics because there are neither
polys nor strips in its input.  It would be much more convenient if it would
just pass the data through in this case (perhaps with a warning), rather than
give up completely.  I can fix this myself without changing the library by
deriving a new class from vtkPolyDataNormals, so that's not such a big deal.

Second, vtkTensorGlyph::SetScaling() and family has no effect.

Finally, when using vtkAxes as a glyph, I've noticed that sometimes the lines
are the correct color, and sometimes they're black.  It seems to depend on
the camera's orientation.  I would like the lines to have the same color
regardless of what direction I'm looking at them from.  Is there a way to
do this?  This is the most pressing issue for me.

Thanks for any advice,
John Norris
Research Programmer
Center for Simulation of Advanced Rockets

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