Constraints Not Working Properly With Referencing In Maya 7

[animotion3d]

Hi,

We are facing a problem with Maya 7.
if any prop which is having constraints is referenced more than one time in Maya 7,
after animation when we reopen the file the controllers and animation will be there but the Mesh of that prop doesn't show.
So if we unload/reload reference of that prop the Mesh will come up,

any idea why this is problem?
and referencing is not properly working with aimConstraints also.

any comment will be helpful,

[gmask]

Well it sounds like a problem with the naming.. are you using names spaces?

This is sort of a workaround but you coudl try just making a copy of the referenced file and naming it differently and then refering it.. this is probably fine if you only need to reference it a few times.

[animotion3d]

Its a problem with same file,

I ran a test , where I made copies of that asset file,
and then referenced all of them,

and it worked,

so its a problem with referencing a single file multiple times.

any idea how to solve this?

[joojaa]

This is a rig design issue. Referencing does not work if your model inst adherring to the dg very rigourously, thus all expressions you use must be built to support dg in other words no MEL in expressions! So any querry that would just reference to something via a gap in the dg has absolutely no chance of survival.

Anyway maya 7 has a few serious known bugs that cant be circumvented beyond going to maya 8.0 or 8.5 which did some significant fixes on referencing.

[animotion3d]

hi joojaa,
thanks for reply,

as you said there are lots of exressions in the rig files, so that could be the reason for crashing of constraints,

but if that be the case, this problem might be coming to everywhere, and any working solution must be there to avoid it,

so in your opinion we should use connections with utilities instead of expressions for calculations , right ?

and one more thing, just for info,
are you joojaa from sourceforge.net?

thanks again,

[joojaa]

QUOTE(animotion3d @ 07/27/07, 02:05 PM) [snapback]270505[/snapback]
are you joojaa from sourceforge.net?

Yes.
QUOTE
so in your opinion we should use connections with utilities instead of expressions for calculations , right ?

No thats not what im saying, just no MEL/PYTHON inside EXPRESSION language.

Well see heres the thing, expressions arent equal to mel but expressions eat mel quite happily. Theres a sort of people that THINK they are equal but theres a big difference. And that is if i type:

objectA.translateY=10; //this is expression syntax

it effectively equals to me writing the following mel

setAttr objectA.translateY 10; //this is mel syntax!

However theres a BIG difference. objectA.translateY=10; gets compiled into a node as a input connection to the expression node. setAttr objectA.translateY 10; will just be saved as a literal string to be executed. Now it so happens that maya nodes don't not know the names of stuff in the scene. So if you were to reference the later it would still point to objectA.translateY whareas the first would reference to whatever it is connected to!

But thats only the paek of it the later is also 10 times slower and also prone to way much more error for a number of reasons. Most prominently ist a dg nde thats acting against the dgs design. SO if it feels like hitting your head against the wall its because you in fact are doing just that.

theres no way of solving use of mel in the nodes im afraid, without always preprocessing all expressions after reference. But for obvious reasons this is stupid. Mel is just not designed to be called form expression nodes, just because you can does not mean you should. (maya 8.5 supports api load filters you can solve it with that easily, but dont theres a reason it works like this)

After all it is possible to go but trough the balcony even if its at 10 floor, but for some strange reason people prefer elevators. Its the same kind of subtle difference. Maya does not care how much easier it is to shift the furniture out the window, instead of trough the door and elevator/stairs because ultimately in the end cleaning up your mess is more work for maya.