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View Full Version : Lost in xpresso hierachy jungle, Need advice

tcastudios
10-13-2004, 11:45 AM
I'm a basic Xpresso user, (often) getting simply setups to work.
I have a basic idea for a type of a "Crowd/Follow Leader" idea as well as a training in Xpresso.
I have no problem getting one (Slave)object follow a (Master)object, using the history node.
What I haven't managed to do is to make a group of slaves under a Null to follow the leader one after each other in a simple way.
I have come to the point where all slaves behave as one, they move exactly the same.
What I'm looking for is to pass the history from the first slave to the second, then from the second to the third etc.
Ultimately the amounts of slaves would have to be taken care of automatically.
That is, I would like to use any amounts of slaves under a null, and they will still follow.

The effect could be described as an "echo" of movement/rotation etc.
I'm studying iteration-, objectlist-, hierarchy nodes etc. but are stuck..

Would this be, relatively easy to do? Or should I just forget it? I have at this point no time going into C.O.F.F.E.

Cheers
Lennart
Srek
10-13-2004, 12:17 PM
Hi,
it's not ot hard to do. You have to use relative references for object nodes so an object uses a memory node fed by it's predecessor on the same hierarchy level. This way you can copy an object with this expression numerous times and each will take it's predecessor into account for movement.
If i remember correctly i did the multipede example with this technique http://www.bonkers.de/r8/xp/xp.html
Cheers
Srek
tcastudios
10-13-2004, 12:40 PM
thanks, Srek. I'll take a look and make a try from there. I'll most likely come back since there is one more "level" of this idea. I already have a MasterNull with a xpressoTag.
in that Tag I have two Linknodes where I put the MasterObject and SlaveObjects Null.
This way I can animate what object influence the slaves and change slaves as well, on the fly. (Robotarm exchange, birds changing direction etc)
Later (after I tried a basic settup) I'd like to be able to animate the amounts of slaves, and hence have them automaticaly "see" each other..but that's later.

Cheers
Lennart
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