[vtkusers] which vtk classes to use?

[David.Pont at forestresearch.co.nz]

Hi Lisa,

   if spheres (and their random points) are pre-calculated how about
vtkProbeFilter with a vtkPlaneSource as Input?

Or you could just sample your field 'on the fly' using the probe filter
concept:
Create a vtkPlaneSource, place it with SetCentre, SetNormal, use
SetXResolution and SetYResolution to suitable values (probably quite high)
for sampling your 'field'.
Create a vtkStructuredPoints with dimensions matching the plane resolution.
Traverse the points in the plane, at each point generate your spherical set
of random points, calculate the average velocity value and insert this
value (may need manipulation) into the structured points at the appropriate
location.
Create a vtkTexture and set the structured points as input.
Pass the plane to a mapper, then actor, apply the texture to the plane with
actor->SetTexture.
This should give an 'image' of the velocity field pasted onto the plane.
There are probably alternatives that output data sets other than structured
points, eg polydata.

  Dave Pont



                                                                                                               
                      "lisa hughes"                                                                            
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                      20/02/2004 08:05                                                                         
                                                                                                               
                                                                                                               





so basically I just need an idea for the pipeline...

Thanks again ,
lisa


>
>Hey vtkusers,
>
>Say I already have a 3D unstructured mesh
>
>and I have generated points which I seed within this mesh via a random
>gaussian generator of spherical shape.  So basically i have a bunch of
>'spheres' at various locations (inside my 3D mesh), and inside of each
>sphere are points that have been randomly generated.   Then for each
sphere
>I have one scalar value associated with it (say an average velocity value
>of all the points that were contained within that one sphere)
>
>and I would also like to slice through the mesh according to some normal
>and then color code the sliced mesh according to velocity info I have (via

>those random points within each sphere location)
>
>So far, I was able to just color code just the points that I've seeded, so

>basiclaly u just see a bunch of discrete points, of some color, within my
>3D mesh (i didint slice it yet)
>
>but say i want each of my 'spheres' to take up 1 mm squared of my screen
(i
>dont know how many pixels that would be?) and  i want to color-in those
set
>of pixels according to that single scalar value associated with that
sphere
>
>how can i represent this?
>glyphs?? i have no clue where to start at this point!
>thanks in advance!! any help is truly appreciated
>
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