Removing Elements Of An Array Attribute

[dcrowley]

I have an attribute that is defined as follows:

CODE
    MFnNumericAttribute  nAttr;    
    m_lodDetail = nAttr.create( "lodDetail", "ldt", MFnNumericData::kFloat, 0.0f, &status );
    nAttr.setArray(true);
    nAttr.setKeyable(true);

I want to be able to remove elements from this array attribute, preferably with Mel, but I can use the API if necessary.

Thanks!

[joojaa]

Contents or reservations? See maya does not clear reservetions untill you load again.

So if you connect to array sloit 10 and dicionnect maya will for thet session allways tell you theres 10 slots in that array. Howvere it can be 10 empty slots. wich is the same as no slot for maya.

You should also try to dicern the difference between a reservation and a used attruibute.

Anyway you can clear this with mel, what you do is you create a empty array attruibute and connect it into theis now slotted attrib, it gets then cleared. you can now disconnect and so on.

Also note theres a difference betweena array of atributes versus a atribuite array they are 2 separate things be sure you understand wich you realy want. The later is allways cleared whjan written in.

[dcrowley]

OK, trying to get this to work. Not sure what I'm missing.

I couldn't get it to work on the dependency node's built-in attribute,
so I decided to try first with just dynamic attributes:

createNode unknown -n node;
addAttr -ln test1 -k 1 -multi node;
addAttr -ln test2 -k 1 -multi node;
setAttr node.test2[0] 23;
setAttr node.test2[2] 42;
setAttr node.test1[1] 64;
connectAttr node.test1 node.test2;
getAttr node.test2;
// Result: 23 42 //

I was expecting the same as:

getAttr node.test1;
// Result: 64 //

So I assume I'm not understanding what you've said.

Regarding what I really want, I don't have control over the dependency node plugin that I am trying to work with. I would bet that they may be better off using an attribute of type doubleArray, instead of an array attribute of type double. so it goes.

[joojaa]

Oh yeah that yes elementary mel types cant be cleared thisway because they work differently somehow (i think its the caching mechanism). But some types like selection lists can (or atleast used to havent tested this since maya 4.5) do it provided you pushed in a new list of somekind form another API node (if i mimic this with mel it again does not work). Havent tested since maya 6. But wether its the usages bookeeping thets doing this i dont know. Just recreate the node. (you can allways connect the old date in and disconnect to do apartisl duplicate)

connectAttr node.test1 node.test2;

does not actualy do anything its just connecting two dummy atributes.

The reason for this si simply the fact that maya sparse arrays are hashes of somekind and hashes dont clear stuff formthemseles very well without full recreation.

[dcrowley]

Yup, I've ended up re-creating the node, and this works.
It feels a little heavy handed, but it's fast enough for my purposes.
I only really need to re-create one node at a time in "UI time".

Thanks for your time!