Jul 2001
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Jul 2001
Jul 2001
benrickel
Jul '01

I am newbie in maya
i am bit confused with the heirarchy thing.
For eg: if we create a nurbs sphere and open the hypergraph we see the follwing nodes in the follwoing heirarchy

                      [makesnurbSphere]

[makesnurbSphere]-->[nurbSphereshape]-->[initial shading group]

What i understand is that

[makesnurbSphere] defines the transform node of the shpere i:e defining its local axes attributes in the world axes.

[nurbSphereshape] defines its actual physical shape attributes like the radius etc.

[initial shading group] defines the ojects shading group.

and

[makesnurbSphere] is the parent of all the above mentioned three atttributes.

when we open the atrribute editor for the shpere we see

[makesnurbSphere]-->[makesnurbSphere]-->[nurbSphereshape]-->[initial shading group] in the downstream graph.

My query is that why there isnt a link showing between the parent [makesnurbSphere] with the others in the hypergraph. my sole purpose is to understand the heirarchy structure in Maya so that i can have a firm grip over using construction history as well.

What does these Downstream and upstream graph actully means.

I would be happy if u correct me if anywhere i have gone wrong in understanding the fundamentlas of Maya and u tell me everything about the Base work flow of Maya.

Thanx.

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    Jul '01

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joojaa
Jul '01

Short answer. Maya hides most of the nodes by default so that you wont have 100-10 000 nodes showing when working on a medium to large sized scene.

If you want to se all of the history nodes select the objects you want to inspect and press show upstream/downstream. Or you can configure the hypergraph to show such nodes by default

campbell
Jul '01

Hey.

I suspect you are gettin a tad confused between hierachical relationships in a scene (DAG) diagram, and the flow of information in a dependency graph (DG) network.

Hypergraph will display both of these relationships. Hierachy usually refers to the relationship between transform nodes, with tranform information being inherrited down the trees. You see this description when you press the Scene Hierachy button (of Graph>Scene Hierachy). If you then decide to graph the up and/or down stream connections, the hypergraph is displaying node connection relationships in a more universal fashion, as a dependancy graph, information flowing left to right (or top to bottom).

I think you may have had a few typos in your post, where you repeated your descripton of [makesnurbSphere] twice, i assume you just ment [nurbsSphere] for one, the transform node, ...which i think you also ment as the first node in your 'diagram' of the up'n'down stream connections. I think you might have done it again when asking why [makenurbSphere] (Read [nurbSphere]) doesnt display a connection to the other nodes. This is because it is a transform node, and as such, doesnt really offer any information regarding the 'make-up' of the object, it just decairs where it'll be dumped in space (plus a few local axes/display attribs).

Hope this addressed your question, perhaps rephrase otherwise. Fairly subtle, but important, distinction between the two types of node relationships. Scene = infromation flow through transform nodes, DG = flow of varrying information types through myriad of non-transform nodes.

C.

benrickel
Jul '01

Hi campbell, thanx for it.
Yes indeed there was some mis quaotation from my side.
Any way would be more specific about the DAG and DG.

Look i am looking for understanding all the node system in Maya and for that u can tell me anything thast relevant to the topic. Thats all i meant in my query.

cause i am new to the 3D world and everythings so messed up with maya that i dont know where ia m presently now, although i have got a good hand at modelling and animations.
I see that the node sytem is very basic and imp so i need to understand it.

Thanx pal,,,,,

campbell
Jul '01

Hey.
Umm. dont think i can be much more specific. You'd probably get mroe from reading the Docs (again?).

Im not sure how deep you want to go, nor how much you already know. At the risk of pointless, and perhaps insulting (tho not intended) suggestions, I suggest you just play around with a simple scene, mouse over the connections and try and figure what attributes and values are being ported between nodes, sometimes this will be easy, sometime a bit obscure. Open the Connection editor and load the nodes in, look through the different attributes (both inputs and outputs), see which ones are compatible for connecting (whethre they are greyed out or not). RMB the nodes for shorter lists of connectable attributes, and probably a little more digestible names. Forge your own connections and watch new connections being forged automatically when you do operations. You might want to check the Docs for the Node and Attributes Reference, to get a better understanding of what the names mean.

I dont think i can offer much more, but play, its the best way to develop a greater understanding of the system. Like someone said in another thread, its not as if your going to break your computer by messing around with node networks.

Good play,
C.