Re your question: why not import u and v as 2-vector float data on the 2-vector positions? Seems to me that Streamline requires a vector field and you are providing it a scalar field (U) and another (V).
You need to learn about Print, esp. Print("rd") which can be attached to any output to see what is flowing in the 'pipes'.
This will determine the type of object. I suspect you are getting a Group of 2 Fields, which is a general purpose object and not a suitable input to some modules that can't deal with arbitrary polymorphs like Group. So first try Select(0) on the output of Import, prior to Streamline.
But I still think you want to join U and V to make [U,V].
On Wednesday, Jun 9, 2004, at 10:50 America/New_York, Fabian Braennstroem wrote:
Hello,_______________________________
I am still doing my first steps with OpenDX. Now, I see at least my first 2D
velocity data with those easy to use 'AutoColor', 'Rubbersheet',...
Unfortunately I still have a problem with streamlines.
My import-data have following easy structure
1 1 x x
2 1 x x
3 1 x x
1 2 x x
2 2 x x
3 2 x x
The columns represent the x-, y- coordinates and the u-, v-velocities at those
points.
To read in those data I use following general-file:
file = /home/fab/opendx.dat
grid = 3 x 2
format = ascii
interleaving = field
majority = column
field = locations, field0, field1
structure = 2-vector, scalar, scalar
type = float, float, float
end
To display the velocities with a rubbersheet, I use the modules:
DXLInput, Import, Rubbersheet and Image. That works fine without any further
adjustment.
Then I thought I could do the same to display streamlines, but there I get
following error-message:
Begin Execution
ERROR: Streamline: Bad parameter: data must be a field, multigrid, or composite field
Does this mean that I have a wrong general-file? If so, am I not able to use
the same general-file for different visualizations?
Greetings!
--
Fabian Braennstroem
Duesseldorf/Berlin
Chris Pelkie
Scientific Visualization Producer
622 Rhodes Hall, Cornell Theory Center
Ithaca, NY 14853
