Get Worldposition Of The Locator Node

[ryan47]

Hello all,
I'm trying to create some kind of a modifier for geometry mesh data.
The modifier takes lots of inputs from multiple locators, and recompute internal data and refresh the mesh based on the info comes from multiple locators. Each locator, at least, has four attributes, and users may add multiple locators to achieve their purposes.

In order to make the connections between DeformerNode and other LocatorNodes as clear as possibile,
I compound all attributes(include world position) into a parent attribute, then use this compound attribute for connection. When I connect DeformerNode to LocatorNode upon the compound attribute,
I found "only" the world position attribute is incorrect(always get 0, 0, 0). However, when I manually make a connection for worldPosition attributes once again, I could get the correct result.

I think maybe I define inappropriate type for worldPosition in my DeformerNode...

CODE
MFnNumericAttribute nAttr;
posAttr = nAttr.create("position", "pos", MFnNumericData::k3Double, 0.0, &stat);
nAttr.setArray(true);
nAttr.setCached(false);

How to solve this problem?
Is there any way to get the correct result with one compound connection only?

Thanks in advance.

Ryan

[12monkey]

sorry I cant answer your question, i'm really a noob in MAYA API.
But I really want to know how did you make your compound Attribute which include locator's existed attribute, did you make a dynamic compound attribute on a existed locator or did you make your own locator which should derive from MPxLocatorNode??

Thanks in advance.

[rob-bateman]

QUOTE(12Monkey @ 03/14/07, 08:05 AM) [snapback]262177[/snapback]
But I really want to know how did you make your compound Attribute which include locator's existed attribute, did you make a dynamic compound attribute.....

MFnCompoundAttribute most likely.....

QUOTE(12Monkey @ 03/14/07, 08:05 AM) [snapback]262177[/snapback]
on a existed locator or did you make your own locator which should derive from MPxLocatorNode??

I'm guessing a normal locator node.

[rob-bateman]

QUOTE(Ryan47 @ 03/12/07, 02:54 AM) [snapback]262011[/snapback]
I found "only" the world position attribute is incorrect(always get 0, 0, 0). However, when I manually make a connection for worldPosition attributes once again, I could get the correct result.

use the worldMatrix attribute which should sort the problem.

[ryan47]

QUOTE(12Monkey @ 03/15/07, 12:05 AM) [snapback]262177[/snapback]
sorry I cant answer your question, i'm really a noob in MAYA API.
But I really want to know how did you make your compound Attribute which include locator's existed attribute,

As Rob said, I use MFnCompoundAttribute to compound all attributes...

CODE
MFnCompoundAttribute compFn;
locatorAttr = compFn.create("locatorAttrs", "locAttr", &stat);

// Create child attributes
//
MFnNumericAttribute nAttr;
radiusAttr = nAttr.create("radius", "r", MFnNumericData::kDouble, 5.0, &stat);
forceAttr = nAttr.create("force", "f", MFnNumericData::kDouble, 1.0, &stat);

// Add child attributes to the the parent attribute
//
compFn.addChild(typeAttr);
compFn.addChild(radiusAttr);

// Add attributes to node
addAttribute(typeAttr);
addAttribute(radiusAttr);
addAttribute(locatorAttr);

QUOTE(12Monkey @ 03/15/07, 12:05 AM) [snapback]262177[/snapback]
did you make a dynamic compound attribute on a existed locator or did you make your own locator which should derive from MPxLocatorNode??

Thanks in advance.

In my case, I make my own locator derived from MPxLocatorNode.
Since I want to connect my LocatorNode to my DeformerNode by one compound attribute only.
Therefore, I compound all attributes in LocatorNode and DeformerNode respectively, and all the child attributes in these two nodes are created in the same order...

Hope this helps

Ryan

[ryan47]

QUOTE(Rob Bateman @ 03/15/07, 12:37 AM) [snapback]262182[/snapback]
use the worldMatrix attribute which should sort the problem.

Dear Rob, I have tried to use worldMatrix attribute, and I find something weird...

I create another attribute "outWorldMatrix" in my LocatorNode to hold the worldMatrix from its transform node. Then I make a connection to its transform node, and override its compute function for data updating. Before I connect LocatorNode to DeformerNode by compound attribute, the "outWorldMatrix" returns the correct information... However, when the connection is made, it would no longer update the "outWorldMatrix"...

This situation is the same as I used the worldPosition attribute. Making a connection manually only could get the correct value of that time, and the value won't be updated later!!
I guess this maybe the reason why it doesn't recommended to connect an array plug to another array plug in maya. ("worldMatrix" or "worldPosition" in compound attribute is an array plug...)

I try to directly connect the worldMatrix of transform node to DeformerNode's worldMatrix in compound attribute, and all things work fine... data are updated correctly!

So far, I still failed to connect two compound attributes that have an array plug...
Have anyone solved this problem?

Ryan

[rob-bateman]

I always get the correct results within compute from worldMatrix?? you are extracting it using MFnMatrixData i assume?

[joojaa]

This sounfds like theres some serious design issue at hand here. Do you understand exactly how DG is supposed to update?

[12monkey]

Firstly, thanks very much Rob Bateman and Ryan47. Thanks for the greate tip

Secondly, I do know a little about DG's update. Dirty message propagate, and only calculate the attribute which is needed. Is that right? But in this particular case, could you offer some concrete tips? Thanks very much

[ryan47]

QUOTE(12Monkey @ 03/15/07, 09:39 PM) [snapback]262233[/snapback]
Firstly, thanks very much Rob Bateman and Ryan47. Thanks for the greate tip

Secondly, I do know a little about DG's update. Dirty message propagate, and only calculate the attribute which is needed. Is that right? But in this particular case, could you offer some concrete tips? Thanks very much

Hi 12Monkey,
I'm still a newbie too. Sorry, I can't offer you concrete tips,
I only can share my experience during these debugging days...

The first is about the DG's update.
If we connect two nodes with compound attribute and use the custom manipulator to modify some child attribute, it would pass the update event for the compound attribute (even if only one child of the compound attribute is dirty...)
However, if I modify the child attribute by mel command, it would first pass the update event for the specified child attribute, then pass the update event for compound attribute again...

I test with the following code in compute() ...
CODE
if(plug == compoundAttr)
{
   int iChildNum = plug.numChildren();
   for(int iIndex=0; iIndex<iChildNum; iIndex++)
   {
       MPlug childPlug = plug.child(iIndex, &stat);
       bool bClean = dataBlock.isClean(childPlug);
       if( !bClean )
       {
             if(childPlug == omatAttr)
             {
                 //....
                 dataBlock.setClean(childPlug);
             }
        }
        //.... deal with other child attribute  
}
else if(plug == omatAttr)
{
   dataBlock.setClean(plug);
}

The other is the memory issue when using attributeAffects() during initialization.
I found that if I use the compound attribute as the parameter in attributeAffects(), the memory it costs would be much more than the cost when I set the dependency of each child attribute respectively. (In my own case, the extra cost is about 40MB.)

Sorry for my poor English,
Hope this would help~

Ryan47