Get U Parameter On Curve From Object's Xform?

[almakos]

Hi to all.

I have animated object.
I need to create a trajectory (motionTrail); convert it to a curve; find U parameter on curve where at the current moment object is (at least approximately).

to convert trajectory to a curve I have used script found on this forum...now I wonder how can I get U parameter according to object position, 'cause object and curve are not linked in any way

[joojaa]

what did the script look like?

[almakos]

that was your script, Joojaa as I remember, can't find link at the moment:

CODE
{
$list=ls -dag -sl -et snapshotShape;
for ($item in $list){
  $pts=getAttr ($item+".pts");
  int $len=size($pts)/4;
  $crv = curve -d 1 -p ($pts[0]) ($pts[1]) ($pts[2]) -k 0;
  for ($i=1;$i<$len;$i++)
    curve -os -a -p ($pts[$i*4]) ($pts[$i*4+1]) ($pts[$i*4+2]) $crv;
}
}

I can hardly understand it though. and I still haven't found way to get u data I need

[joojaa]

Yes just wanted to know which of theese scripts it was. * I knew ther was a high likelyhood it was mine. I dont actually usually use those scripts myself mostly, i just write them ad hoc directly out of my mind.

The u should be the framenumber - start offset or (framenumber-startoffset)/totalFrames. No maya at hand to test for sure. Its either or.

Anyway its rather easy to know for sure by using the devkit closets pointOncurve node.

*oh yes thats mine alright one can spot the style a mile away, anyway i car remember writing this one its by the way teh 4th iteration of the same script

[almakos]

I see, thank you for this method, I'll give it a try

P.S. awesome script btw, thanks. using it with pleasure

[joojaa]

Hmm its not its chord length that makes it a bit more comvoluted. Let see if i can do something about it.

[joojaa]

CODE
{
$list=ls -dag -sl -et snapshotShape;
for ($item in $list){
  $pts=getAttr ($item+".pts");
  int $len=size($pts)/4;
  $crv = curve -d 1 -p ($pts[0]) ($pts[1]) ($pts[2]) -k 0;
  for($i=1;$i<$len;$i++)
    curve -os -a -p ($pts[$i*4]) ($pts[$i*4+1]) ($pts[$i*4+2])  $crv;
  rebuildCurve -ch 0 -rpo 1 -rt 0 -end 1 -kr 2 -kcp 1 -kep 1 -kt 0
               -s 0 -d 1 $crv;
  $object=listHistory -lv 2 $item;
  CBdeleteConnection ($object[2]+".tx");
  CBdeleteConnection ($object[2]+".ty");
  CBdeleteConnection ($object[2]+".tz");
  delete $object[1] $object[0];
  pathAnimation -fractionMode false -follow false
              -startTimeU playbackOptions -query -minTime
              -endTimeU  playbackOptions -query -maxTime
              $crv $object[2];
}
}

CBdeleteConnection relys on channelbox having been visible in your maya once during the session (yes that means im being lazy). Thic converts the trail to exact path anim for tweaking like geometry

[almakos]

wow, this one is amazingly usefull. I have encountered many people asking for a this kind of workflow workaround in Maya. Guess you should promote it in some way...

Once more, thanks
100% usefull

[joojaa]

QUOTE(Almakos @ 04/19/09, 01:13 PM) [snapback]306179[/snapback]
I have encountered many people asking for a this kind of workflow workaround in Maya.

Well that i can believe, they should have asked somebody who can do scripting. Im not sure i could call this a workaround tough, or at least n deeper scope. After all using a computer t do 3d art IS a workaround in it self. But yes i could do this considerably better too if i would see a real need for it. I could make it into a node.*

What this boils down to is however one of my permanent curses. It appears to me that people are very quick to demand that they should be entitled to something. I must admit that this does apply to me myself too, but im trying to actually rid myself form this issue. This issue is very widespread and deeply grained in western culture and business world. The final matter doesnt change tough, if you can not do it, then the blame falls on you. Irrespectively WHO should have done the work for you. From your clients and your works perspective its all the same who makes it work as long as it does work.

So at the end of the day the only way to rid yourself of this kind of limitation is to recognize that no matter who should have done it sometimes you must make amends for other peoples shortfalls, if that mean sfixing it yourself no matter how hard so be it. It is convenient to be victim, it just doesn't help anything.

Like i said i did this one per request i have no greater need for it myself. Its a gift form me to you you are free to do anything you wish with this info. Since i cat for earth of me find a way to make this sort of info pay me any money and at the same time maximize the works usefullness**. I do this purely because of the philosophical reward i get form it. sometimes i miss my own goal by miles but hey that happens.

• I find that going further than this is not worth it to me as the kind of ground cost for me developing the pieces to final, starts costing me money. And i cant justify on top of giving my time giving my money away.

** i know many people do but i have philosophical grounds not to do so if thet means slightly less money so be it.

QUOTE
Guess you should promote it in some way...

I promote a lot fo good work flows all one needs to do is care to read. Its just that somehow every time i try to do something out of man to man scope it seems to get perverted so much its no longer worth it.

It is as if people WANT 3d graphics animation and simulation to be total incomprehensible magic to them. I exact price in way that many see too costly.