Getting "Extra Attributes" data from Maya

[thetutor]

I'm working on a Maya exporter and have run into a bit of a snag.

I'm filling in the "Extra Attributes" section under the Attributes Editor with a simple MEL script. Here

[gdc]

This may not be the best way, but if you know the name of the extra attrs you could always querry there values.

//----------------------------
int $value=getAttr ($allShapes[$i]+".DoNotRender");

Hope that helps
--g

[scifiwasabi]

I don't think maya distinguishes between a node's built-in attributes and dynamic (custom) attributes.

Any non-hidden attribute that isn't handled by its node's AE template automatically gets placed in the Extra Attributes section of the AE.

If you don't know the names of dynamic attributes ahead of time then one guess would be to create a fresh new node of the same nodeType as the current node you're processing. Then count the number of attributes in the fresh node. If the current node's attribute count is higher then it has dynamic attributes which start at that count index. Well...I'm guessing coz I haven't tried this myself.

[thetutor]

Is there an easy way to execute a MEL script from within the API?

I'd love to be able to just call getAttr but I'm stuck in the bowels of exporter that only uses the Maya API.

[thetutor]

Never mind. Found it )

MGlobal::sourceFile() executes a MEL script

I'm going to try and reverse the script and execute from the exporter. I'll tell ya how it goes.

[thetutor]

Well.... Not so good

Does anybody know how to get information from a MEL script easily into the API?

Better yet, I'm still looking for a way to get the attributes by only using the API. The way the exporter is set up this is the most convenient straightforward approach.

[gdc]

will MGlobal::executeCommand() work??

--g

[thetutor]

Sure will

Thanks for the help guys.

Here's a quick overview of how I solved the problem:

// I run through the dagPath

if (dagPath.hasFn(MFn::kMesh)) // If we have a mesh
{
status = outputMatProps();

objectId++;

if (status != MS::kSuccess)
	return MS::kFailure;

}

outputMatProps()
{

MStatus status;
MString command;
int result;

command = "getAttr ";		
command += partNames[objectId]; // List of part names extracted from dagPath.fullPathName()
command +=

[scifiwasabi]

Its ok to use mel with MGlobal::executeCommand() as long as the mel code is just querying attributes or maya state or setting variables or optionvars etc...simple stuff. Anything more complex will make it harder to implement undo. If you need to undo then it is better to execute your mel thru an MDGModifier.

Anyway, you can get your attributes in API like so (since you already have your dagPath):

MFnDagNode fnDagNode(dagPath);
MPlug dnrPlug = fnDagNode.findPlug("DoNotRender");
bool doNotRender;
dnrPlug.getValue(doNotRender);

[jeffd]

It looks like you might be beyond this point now, but it was never mentioned that you can list all of the dynamic attributes with the MEL command

listAttr -ud

--JeffD

[scifiwasabi]

Good one JeffD...I totally forgot about that flag. Made me wonder if I missed a similar method in the API. Anyone know if you can directly find user (dynamic) attributes? I noticed in MFnDependencyNode there is an MAttrClass enum that defines kGlobalDynamicAttr and kLocalDynamicAttr. kLocalDynamicAttr appears to be what we want but it only seems to be used when adding and removing attributes but not for querying.

[thetutor]

I like the dagNode method a lot better. I'll be using that. Thanks.

I believe I've seen a post about "always adding extra attributes" to an object. Right now you have to run a script before you can add attributes which the artists fine cumbersome. I