References and Reference Editor

[soeasy3d]

Hi!
Right now we disided to use references at our production pipeline (3d game). At first look Reference Editor needs a lot of impuvements. But it would be so easy with mel. My question: Do you know any CONS of using references at production? I know many PROS, I just worring about CONS.
Good luck!
soEasy3d

[soeasy3d]

hi!
Anybody use references at all?

[gnip]

Greets!

I've worked with references for awhile in production ( film, video and games). My suggestion is test referencing and get very familiar with how Maya handles references before choosing to use them. They work... but they also add another layer of complexity that can be tricky to unravel at times. It is a complicated beast, so know what you're getting into... Read all of the documentation you can find, and then do a lot of testing on your own.

(Note: When I refer to a "master file", I'm talking about a file that contains a reference to another file.)

Some issues to look into:
* Understanding how the nodes are prefixed when referenced in
* Know the rules about what you can and can't change in both a referenced file and the master file such as the changing of attributes and making/breaking connections (best learned by personal experimentation)
* Referencing a file that already contains references
* Since prefixes are added to node names for files that are referenced in, experiment with what Maya automatically does to expressions to
keep the node names consistent.

One specific heads up I will pass on... I call it the "masking setAttr" issue... It's a bit hard to explain, so I'll try to make this as clear as I can:

Say you have a blue sphere in file A. You reference it in to file B 3 times. You tweak the material color on one of the spheres a few times and then decide to set it back to a blue. You save off file B. Then, you later realize that you really want all your spheres to be green. So, you think, "Hey, I can go into file A and change the color in one place and have it update all 3 of them!" So, you open file A, edit the material color to green and save file A. Now, you open file B and notice that 2 of your spheres are green but one of them is still blue! What gives? Simply, when you do something in file B that causes an attribute to be set, this settings in B will now forever "mask" that attribute value in file "A". This is usually what you want. But, there are cases where this is not the behavior you would like. I know of no way to "unmask" something other then hand editing a .ma file. Anyone else have any experience with this?

The "masking" happens because of lines that look like the following at the end of the .ma file:

select -ne p2_blinn1;
setAttr ".c" -type "float3" 0.16900003 0.20404051 1 ;

If you delete this line, the "masking" will go away. But, as always, tread carefully when hand editing a .ma file!

A few other file referencing tips are on: http://aw.aliaswavefront.com/pit/maya/mayaqueen/index.html (follow the "Tips" tab and click on the link for "Notes on File Referencing")

Hope this was helpful and not re-iterating what you already know. And, everyone else, please correct me if I said anything wrong.

[soeasy3d]

Hi, Gnip!
Thak you for "maskin atttrs". It what I want to hear.
Something that happend when you work a lot with references. Right now I wrote some mels for working with a bunch of references at once. Selecting, removing, make them a bbox and so on. And I think this is a good point to use *.ma files. Just to feel yoursrlf more safe.
And once more, thank you Gnip!

[joojaa]

One other thing that can be usefull is to have one node that controlls all the data trafic in between the reference and its parent. Thisway if you choose to do soem mooodifications under the hood as long as you dont do any incoming stuff for the connectoion table (in lacking a better term). You are ofcourse free to add things to it but not to remove unless you can be sure no referencing file is inputtimng to that atribute.

the benefit is that now you will know exacly the place where all inputs will be connected (ok you can have many of theese if its more convinient to use naming conventions). Or you can store all in sets... And write a mel that locks theese if the file is opened to protect them from accidental tampering. Ofcoures you need one to unlock them on exit or youll be screwed!

[captainsam]

One thing that can be a huge pain in the @ss is the fact that once something is parented to the reference, it can't be replaced, unloaded or removed. The same goes for compound attribute connections, which are used by constraints, among other things. You'll either have to remove these children and connections manually, or replace the reference by editing the Maya ascii file (never never never use binary, particularly when you have references in the file), which can be a very dangerous thing to do as well.

Ive been working on a script that can handle all this for some time, removing children and breaking compound connections before unloading a reference, then reestablish those parenting relationships and connections when the reference is reloaded. I'll release it sooner or later, but first I neeed to deal with Maya's idiotic way of handling nodenames (the whole thing will break if you have multiple nodes with the same name in the file)

The Maya Queen tutorial says you cant break connections on a reference. This is wrong.

There appears to be some bugs really deep down in Maya related to referencing that will make Maya overwrite the original file youre referencing with an empty file when you save the file containing the references. This happened several times on the last project I worked on. So do keep backups of everything.

I dont remember the exact details right now, but if you create ikHandles locally in the file, but also have a reference containing ikHandles and then remove that reference, the local ikHandles stop working. This is because the local ikHandles (or effectors; dont remember) have been connected to the reference's ikSolver for some idiotic reason. You'll have to reestablish the connection to the local ikSolver manually.

[warpcat]

We use referencing here pretty heavily, and I'd agree with everything said above. Also, I want to reitterate how how much a pain in the a$$ the "setAttr mask" is. I've seen it pop up on constraint connections, object scale, and a few other things. Right now I'm fighting constraint connections. In my referenced scene, at one point I "disabled" all the constraints. Now, no matter how many times I "re-enable" them and save, upon scene reopen, they're still disabled. Very frusterating. In fact, I'm talking with AW right now about a way around this, because it's pretty rediculous how quicly it can turn your data into a pile of smoking rubble.... Hacking the .ma is just that, a hack around a major bug. Rant rant rant I should point out though that the functionality that referencing provides us is definatly appreciated, just wish it worked better.

[gmask]

Now, no matter how many times I "re-enable" them and save, upon scene reopen, they're still disabled. Very frusterating.

Yup.. I jhave had this happen alot with shaders.. or for some reason if you parent an unreferenced object to some part of the hierarchy or a refrenced object the material on the non- referenced object will disappear.. sometimes animation channels disappear.. I dunno what it is but my solution was to just import the references at the last minute and then make my changes.

[warpcat]

Yeh, I don't know what's going on.... I can hack open the ascii, and I actually find the lines of code ENABLING my constrains... I open Maya, the node states are set to "Normal", but the constrains don't work. I go "Modify->Evaluate Nodes -> Constraints" and suddenly my asset starts working. I save. Reopen, same problem, constraints don't work. I can replace the reference or reload the reference and it starts working. Save. Reopen.. .still broken. KILLLL!!!!!!!!

[joojaa]

As for parenting problems they can all be circumvented by having a front in between just as long as the front nodes are first in the scene hierachy and you dont actualy directly manipulate anything! its even good to hack their ids to soething even better

it might seem like a limitation to most but it inst realy!

but yeah having a ma file in between helps you a lot.