I just sent something to the list, but I just thought, do you mean use three Switches?
Fred
At 03:31 PM 7/23/01 -0400, you wrote:
Looks like Greg embellished my answer
with the necessary Compute(a+1) that I forgot. I believe it's the
case that when you data-drive Selector, the auto-generated list
starts at 0 so the Compute bumps everything up one to make Switch
happy. Otherwise, his answer should serve. That is, he and I think
alike that the only place you really need the Switch is just before
the output regardless of how much viz stuff happens between Select
and Image.
You might be thinking you'd save
processing time if you didn't execute unneeded branches at all. This
is where Route (several) would help possibly, but not Switch. If I
remember correctly, Switch branches all evaluate always. Route(0)
branches do not execute. However, this does not always compute, i.e.,
there are some modules downstream of a terminated Route that will
bitch and whine (or essentially not execute at all leaving you with
no image). I fear that Switch is one.
So you might rig up some Computes of
the nature (a == 1 ? 1 : 0) to pass a 1 if comp1 is chosen [and you
feed this Compute's a input with the output of Selector and the prior
Compute(a+1)] but 0 otherwise, to Route. This would execute that
subbranch below Route if comp1, otherwise not execute. Likewise a ==
2 ? 1 : 0 for choice 2. Each branch needs such a Compute and its own
Route with only the 0|1 value and one selected input stream and you
only use the leftmost output (the "1" valued stream; 0
value makes no output stream out of that leftmost output or any other
output for that matter). So now you end up with 3 Routes, 2 of which
do nothing depending on Selector. Collect, Image, season to
taste.
I typically install a whole raft of
Selectors and Routes (usually user-driven) to turn on/off various
objects in the output, so if all you do is Collect and Image these 3
streams (one valid, two null), it should work.
Chris Pelkie
Vice President/Scientific Visualization Producer
Conceptual Reality Presentations, Inc.
30 West Meadow Drive
Ithaca, NY 14850
[EMAIL PROTECTED]
