Force refresh at a given time

[lsebo]

Hi there,

I would need to get my custom deformer node to refresh at given time values. I tried several things, none seems to work fully...

First, I made a mel command that would step through the time range using:

		for (float t = startTime; t<=endTime; t+= sampleRate){
			MGlobal::viewFrame( t );

            .... do  stuff ...

}

This would step through time, but no nodes are refreshed (only when the command returns to maya, effectively the last frame of the range).

I guess i would somehow need to force a refresh, maybe by querying the outputGeometry of the deformer node. How could I do that?

I was looking at the forceCache() function of the node, but thats a private function, so my command cant call it (i am not sure i am supposed to call it from outside).

So I tried to do this using mel, which seemed to work:

float $i;
for ($i=$st; $i<=$et; $i+=$sr) {
	print ("time now is: " + (string)$i + "n");
	currentTime -edit $i;
	refresh;
	getAttr $actualNodeName.outputGeometry[0];
}

While this SEEMS to work (more on this later), its freaking slow, since the whole scene gets updated and displayed in the viewport.

Funny (but super annoying) thing I found out the other day: if i switch tasks while the script is running, it will yet again fail to update at the given times.
I suppose maya figures that if i am not looking, it doesnt really have to do what i am saying...

I would be happier if i could do this thing using the API, since that would possibly be a better&faster solution.

Any advice?

[keilun]

I haven't had the time to test this out but have you given the MAnimControl API class a swing?

Using MAnimControl::setCurrentTime, you can set the DG to a given time value. At that point you can do whatever you need to in order to force an evaluation of that which you wish to update (in this case your outputGeometry). The DG does lazy-evaluation so it should only update that which is required by the computations you request following the time change. I believe calling a MPlug::getValue should update all dependencies on the attribute to which the plug is bound.

[joojaa]

The entire point with the DG is to make sura maya knows what to update and when, and when not to update unneccesery data!

So unless you actualy change something (or if its not displayed or connected forward dont do anything either in that case) dont do anything, is how maya does everything! So if you arent looking maya doesent do anything.

this is also why most maya nodes are connected to time so thet they KNOW whan to update time related things.

Also dont update all... its insane maya only updates the direct dependencies wich in turn speeds things up! Design better.

[lsebo]

Keilun: Thanks for the suggestions, i will give them a try. They seem to be exactly what i need.

Joojaa: Yes I understand how the DG works, it quite easy & logical actually. That given example is a behaviour i wouldnt expect though, since there is a direct mel query for the outputGeometry of the deformer node with changing time (the time is connected to the node, and the outputGeometry is flagged as "affected" by the time), yet it seems to skip the node evaluation if i alt-tab to a different task.

My other problem (not knowing certain classes & functions) comes from the fact that my maya api experience is minimal..

cheers

[joojaa]

If you use getAttr to querry the value it should get updated!

But seriously are you sure you havent left some depependcy untold to maya?