Auto Deleting Of Animcurve

[vlad-d]

Hi,

I connected the animCurve node to may attribute using MFnAnimCurve::create(...), then added some keys using MFnAnimCurve::addKey(...). So key ticks are appearing on timeline.

So if I select some part of my keys and delete it - everything is ok. But if I select all the keys and delete these ones - maya deletes correspondent animCurve node connected as well.

It does not good for me. How I can prevent such behavior?

I want anim curve node ramains alive when user deleting all its keys.

[richie-m]

obviously, there are no keys so the animation curve is deleted... thats obvious... you cant keep it in the scene unless you have at least one key set...

[vlad-d]

yep. thanks.

[joojaa]

Actually it auto deletes it because it has no outbound connection rather than it being empty. So just amke a dummy connection out

[richie-m]

why would you want to keep the animation curve when its empty anyway?

[joojaa]

Well let us suppose you want to copy in a new node, piror to maya 8 it was easiest to suspend automatic node deletion delete the node and then rename the new one as the node and reconnect all non connected aim curves by their name. Wether or not they are empty or not does not matter. maya would delete them with their parent.

Also you might want to keep the animcurve as a placeholder for some future data manipulation.

Also suspending this is nifty for reuse of complex expressions.

[vlad-d]

I need to keep anim node alive when its keys are deleted because I have 'build-in' animation controllers that handles the keys and perform an interpolation (mesh morphing). animCurves are used just for interface with maya to enable user to edit keys on timeline , dope sheet etc. So I need to keep consistency between 'internal controllers' and aninCurve nodes (one to one)

So I do not like when maya automatically deletes an animCurve when I delete all its keys. I got an 'internal conroller' with lost curve node.

So I need to do one of:

a ) delete internal animation controller as well
b ) reconnect it again when adding keys and found that there is no animNode is connecgted to correspondent plug.
like this:

CODE
trackPlug = trackArray.elementByLogicalIndex(idx, &stat);

if(!trackPlug.isConnected())
{
MFnAnimCurve animFn;
animFn.create(trackPlug,&_dgMod(),&stat);
}

I just wander is it safe.
for exampe, if I have tracks 0..5 and animCurves connected to elements of array plug for each of them. So I If delete all keys of track #3 maya deletes curve node #3 but I still have track #3. So when later I want to add the key to track #3 I get elementByLogicaIndex wiht index 3 and reconnect animNode.

Can I be sure that I got actually 3 element? Because it seems maya eliminates elements from array that is disconnected. Is not it?

[joojaa]

Well, thing is you need to enable maya users to do this or you will confuse the jeepers out of them. (not to mention limit the creative use of your node)

What you do is you expose the attribute in the attribue editor this way the user can go and just recreate the curve. by keying this attrib. Now it is not safe, normal or intuitive to read the curve internals over a connection (its a api design no no).

From strict design point of view don't assume maya users connect a anim curve to something, they will connect anything. So if you plan to use some kind of set curve function use a ramp control attribute instead as it cant be deleted and you dont get people trying to run the values by expressions instead.

However you should ennable maya users to connect whatever you like to the attribute as this makes your node about 10^number of nodes more usable even if you cant think of it now someone will in future.

So dont design nodes that are monolithic design nodes that fit into one smal node for each task paradigm. Makes your life so much easier.

Anyway if you intend to do theis recreation no matter what do it as a scriptjob (thats connected via the attribute event) this way at least the user has a choice. (mayas about user choice want it or not)