Questions with listAttr and getAttr

[dannyst]

I have noticed a problem and was wondering if anybody knows what to do. I am noticing that quite often there are attributes that show up on listAttr but that cannot be obtained through getAttr.

For example, if I use the split polygon tool and then enter the following in the script editor:

listAttr -r -w -hd polySplit1;
// Result: caching isHistoricallyInteresting nodeState inputPolymesh cachedPolyMesh useOldPolyArchitecture inputComponents vertices vertices.vtxx vertices.vtxy vertices.vtxz edge desc subdivision//

my particular questions apply to: vertices vertices.vtxx vertices.vtxy vertices.vtxz

I can getAttr polySplit1 vertices, but get no data returned in the script editor. I cannot do anything to figure out what kind of data is in vertices.vtxx though.

I need to be able to use some of these attributes in expressions for my custom tool. I need to be able to create an expression that can move the vertices that are created. The problem is the movement is not obtainable through the polysplit.edge[$i]. The location moved too is actually off the current surface. So I need access to change the location of the vertices at their x y and z level rather than tweaking them via percent of the edge they cut across.

The vertices.vtxx is listed as readable, writeable and as one that has data but anything I ever do to try to access it returns the error that the attribute doesn't exist. listAttr shows it is there, but I cannot get to it.

Anybody know how to do this?

[dbiggs]

I don't completely understand what you're trying to do, but anyway..
Any vertices added via polysplit will have the highest vert index, so you can just go

int $numVerts[] = polyEvaluate -v mesh;
float $pos[] = pointPosition -w mesh.vtx[$numVerts[0]-1];

and $pos will be the x,y,z position of the newly added point

If you've added more than 1 vert in the polysplit just use

size(getAttr polySplit1.edge);
and count back that many verts to get their respective positions.

I'm not sure what the vertex.vtxx etc attributes are actually for either since they don't seem to store any data.

[dannyst]

You got me a lot closer to getting what I want.

I am getting another problem and I am pretty sure I know what the problem is. I need to move vertices that are created and effected by the polySplit node. The movement needs to be driven by dynamic attributes I add to give the user immediate interactive control over the tool. However I cannot manipulate those verts unless I get to them via the parent node (ie polySphere1.) So I run the polySplit command across a sequence of edges and it creates a node that I assume is a child to the polygon object node that is being cut. I then have to manipulate verts that the polysplit created. I can get to those via the parent object, but I get very erratic behavior and a warning message:

Cycle on 'pSphereShape1.pnts[50].pntx' may not evaluate as expected. (Use 'cycleCheck -e off' to disable this warning.) //

So what I think is happening is the expressions I am using are creating a cycle. If I could get the polySplit node's effects to stay while cutting its node out of the DG I think it would work. I can't delete the node because it destroys the cuts that happened. I tried running the polySplit tool with history turned off and that didn't help. I need some way to get those cuts done and have access to the verts created without the cycle. That means I either need to make the polySplit node go away with the effect still in place, or I need to have a way to drive the vertex locations through a node that is a child of the polySplit node or inside the polySplit node itself. I don't know if that makes sense to you. I know exactly what I am thinking but I am having a hard time wording it.

[-coj]

cant you just delete the construction history on the object after you do the split?

[dannyst]

I have tried doing the split with no history. That didn't take care of it. The way the history works would make me think that getting rid of the history should fix this problem. However that doesn't seem to work. Deleting the node itself deletes the edges that are created by the cut. Doing the cut with the history turned off doesn't get rid of this cycle either. I don't know how to delete a particular node's history after it exists. If you know something I haven't been able to find, I would be very grateful for your pointer.

[-coj]

a simple "delete -ch $object;" should get rid of the polysplit node while keeping the added splits.. however this will delete all the history on that object and I dont know if you need it for something else..
if you have a clean object with no prior history nodes on it "polysplit -ch 0 ...." should work without adding any extra nodes..

[dannyst]

That didn't take care of the problem. Thanks for the pointer. I hadn't noticed that delete had the ch flag. II still can't get rid of that cycle. Maybe my idea is not quite right about why that cycle is there.