[vtkusers] I think this is the problem......

[James C. Robinson]

Dear All,

I still haven't resolved my overall problems (getting v4.4 to work the same
as v4.0, implementing the quad hexes etc.) but I am starting to realise part
of the problem. VTK is not documented well enough (at least the online
help). You see, there are many objects which seem to overlap in
functionality (e.g vtkGeometryFilter, vtkExtractUnstructuredGrid,
vtkDataSetSurfaceFilter). How is one supposed to know which one to use? The
descriptions are not detailed enough to indicate why one should be used as
opposed to another, why they are derived off different objects but seem to
achieve a lot of the same thing?

Undoubtedly I am once again displaying my ignorance, but I am really only
concerned with making my application work. My objective in using vtk was
that it seemed to have specifically tailored functionality that fit in
easily with FE analysis. To a great extent it is true, but it is in the
finer detail that I am feeling let down.

My objective is to view a 3D 20 noded (quadratic) hexahedral mesh, with
material, pressure and flow velocity data. I have a MFC C++ (v6) version
that almost works, where I can view and cut the mesh anyway I want. I can
view the flow vectors (as arrows) on any plane, I can view an iso (pressure)
surface, I can even create a streamtube (although this does lock up).
However, I am running into trouble with the v4.2-4.4 VTK releases - I can't
control the transparency of my objects etc. I may be using the wrong
filters.... But how am I supposed to know. Surely there must be a definitive
"best way" to view such a mesh and manipulate in the manner that I want.

Your sin desperation...

Jim

______________________

James C. Robinson, PhD,
Chartered Engineer,
Kepler Simulation Systems Ltd.,
42 Rivergrove,
Glanmire, Co. Cork,
Eire

Tel:         +353-21-4822028
Tel:         +353-87-2393010
Fax:        +353-21-4822028
E-mail:     j.robinson at kepler-systems.com
______________________