The short answer is no. DX does not support FE's edge, face, or body
centered nodes directly. You've thought of the two workarounds, (add nodes,
then cubically connect to existing nodes, increasing the number of
connection elements dramatically; or drop nodes that do not form the
corners of "DX" cubes), so now you pick yer poison.

Remember that DX is a visualization program with some analytical
capability, not an analysis program with some visualization capability, so
you can't expect it to be perfect for all applications, like FE. If in fact
the edges deform noticeably at edge-centered vertices, I'd say you need to
increase the cube resolution by adding a body centered and face centered
nodes and constructing the denser mesh. I would assume (having done this
long ago) that the mesh is not fully regular to start with, so you'll have
to do this connection-generation operation in a preprocessing code that
reads the FE and writes the DX files. If by some lucky chance, the nodes
ARE fully regular in spatial layout, you could use DX Construct module to
recreate a regular mesh with regular cubic connectivity by simply
specifying origins, deltas (of length 1/2 cube), counts (2*cube count + 1)
in the 3 dimensions, then Replace this mesh's positions onto your imported
field as the positions, then Replace the connections of the Construct mesh
also onto the resultant field, and viola, you have a regular mesh of higher
density. It's never that easy though...

On the other hand, do the experiment where you drop the edge centered nodes
and just look at the visualization. If you have a reasonably large number
of cubes in your data object, you probably can't see the difference since
the values of adjacent cubes will interpolate across the boundaries and
smooth the whole representation. I'd do that first. This can be done more
easily (though again probably in a preprocessor) by simply ignoring the
edge-centered nodes when you construct the connections array. They can
happily co-exist in the positions array alongside referenced positions, so
you could still use ShowPositions (and maybe AutoGlyph) to show where they
are and then zoom in to see if the cubic sides that connect corner vertices
deviate too much from the edge centered vertices. If they do not, the
visualization is almost certainly representative of the behavior. If they
do (deviate substantially), you better increase the mesh resolution for DX
(solution 1 above).

(Maybe we better add this to the FAQ, David... it keeps coming up.)

Chris Pelkie
Vice President/Scientific Visualization Producer
Conceptual Reality Presentations, Inc.
30 West Meadow Drive
Ithaca, NY 14850
[EMAIL PROTECTED]

Reply via email to