Undo/Redo on maya mel scripts

[hendrik1979]

I have got a common problem:
I want to change and add some attributes of a polyPlanarProjection inside a script. This script is executed using a shelf button. If I undo these changes made by the script and second I want to redo these changes - without executing the script for a second time - my changes will not be reconstructed.

1) Script creates a polyPlanarProj
2) Same Script sets some attributes to the polyPlanarProj
3) Undo
4) Redo
=> Changes of 2) are not reconstructed!

The reason maybe that maya can not undo single expressions of a script - it undos a whole script. Is that right? Or are there any work arounds to that behaviour?

Hendrik.

[macaronikazoo]

i'm not sure what the answer to your question is, but why are you doing an undo, and then a redo inside you're script?

i'm sure theres a better way to achieve whatever it is you're after...

[amitc]

I can see some good use of it and I did need this thing sometime back
eg:- you are intereseted in checking out some internal state and you dont want your script to run in pieces, debugging could be other reason.

One might consider writing a script with a pause button that ways you can actually traverse some humanly possible no. of steps when script runs. I think that ways even maya would register things in undo stack.

Guess what I tired this
sphere;
$i=0;
while($i<15)
{ move $i 0 0 nurbsSphere1;
confirmDialog;
//pause -sec 5;
$i+=3;
}

Maya does not show any thing till script is finished and undo also does not work

I tried pause command also the results are not available on screen

so just key everything and see it in animation

[hendrik1979]

sorry for this misunderstanding...

the undo/redo is not done by the script but by the user interface using z and Z...

Hendrik

[amitc]

I got that.

Perhaps Maya treats the whole script as one action thus undo does away everything done by script

I was hoping the pause command and confirm dialog will let the result be available at that instant but that is not the case

lets see if some one knows a way of getting this to work.

[keilun]

I can't quite recall the specifics of why this happens (it's been a while since I've touched on MEL execution), but embedding your entire script into a single global proc should allow undo/redo functionality.

Hope this helps.

[amitc]

I tried embedding a script in global proc. It does not regain undo/redo functionality

[subsamples]

i just tried this as a shelf button and undo/redo worked

proc bar(){
string $x[] = polySphere;
addAttr -ln booze -dt "string" $x[0];
setAttr -e -keyable true ($x[0] + ".booze");
setAttr -type "string" ($x[0] + ".booze") "gin";
}
bar;