>Thanks so far, but what do you mean with "marking 'positions'"? (Sorry
>if this is stupid, but I really don't have much experience with DX.) I
>use the visual editor and threw together what I needed using one of
>those example programs (don't remember now which one); I looked around
>but couldn't figure out where I could mark some "positions". What I
>tried until now is to insert a Compute between a Receiver
>"FieldToVisualize" (which is receives the temperature field for one
>frame) and a MapToPlane; that Compute probably should be the 2nd one of
>your description. The main problem for me seems to be how to "mark
>("positions")" for Computing a.z, i.e. how to get the input for that.
>--
Category Structuring, Tool Mark, place in net, open configuration, choose
or type "positions" for second argument. Read the Help on Mark to
understand it. Bottomline: Compute only sees the component of a field named
"data". To work on any other component, it must be temporarily copied into
the "data" component, which is what Mark does for you (it also preserves
prior "data" as "saved data").
The convention for talking about DX in email, etc. is to use the "script"
language syntax (more or less), so a capitalized function like "Mark" means
there is a corresponding tool, then the arguments that follow correspond to
the inputs to that tool. I used an abbreviated form, probably should have
said:
imp_fld = Import(filename);
pos_data = Mark(imp_fld, "positions");
z_pos = Compute( "a.z", pos_data);
T_vector = Mark (imp_fld, "temperature"); //unnecessary if the "data" component
// is the temperature vector already
t_calc = Compute("some expression that combines these", T_vector, z_pos);
Note that you do not (cannot) have 2 or more Mark's in a row without
corresponding Unmarks (like open-close parentheses). Above, the example is
taking 2 wires out of the Import, sending one to Mark("positions") and
another, in parallel, to Mark("temperature"). Again, if you are importing a
data set in which the "data" already IS the temperature data, you do not
need to Mark temperature and indeed you'll get an error if you try to Mark
a component that does not exist by that name.
I don't normally teach Mark-Unmark until a few hours into an intense course
on DX, so this is advanced stuff. You'll have to do some reading on the
data model to understand what's happening. You have to understand "fields"
and "components" to see what Mark, etc. are doing to the internal structure
of data objects.
Chris Pelkie
Vice President/Scientific Visualization Producer
Conceptual Reality Presentations, Inc.
30 West Meadow Drive
Ithaca, NY 14850
[EMAIL PROTECTED]
