Jordi,

Thanks. I think though I’m looking for a broader explanation of what the 
contextual differences are between the network levels.

It turns out part of my confusion may be in part due to the current 
documentation. Today I discovered that the online docs are different from the 
installed ones. For example I discovered that the installed doc page is 
different than its online equivalent for

https://urldefense.proofpoint.com/v2/url?u=http-3A__www.sidefx.com_docs_houdini_nodes_obj_-5Findex&d=DwIGaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=l0u6jf5_k23_sUozgc0HB4nfxCjDEMJFBPXUtV-UffI&s=gCoUBr-Z_tNRR7_veIW2EA6eyUXKFpOeVzMRV-f4aU4&e=

This online man pages clearly explains that Scene Level is strictly for spatial 
and hierarchical relations. Funny thing is there is no mention of this in the 
equivalent installed page. Or anywhere that I’ve searched in the installed docs 
for that matter. Apparently the docs are fluid and its best to use only the 
online version as they appear to be the most up to date.

Time for me to start doing a lot of reading…


--
Joey Ponthieux

__________________________________________________
Opinions stated here-in are strictly those of the author and do not
represent the opinions of NASA or any other party.







From: softimage-boun...@listproc.autodesk.com 
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Jordi Bares
Sent: Saturday, October 21, 2017 10:13 AM
To: Official Softimage Users Mailing List. 
https://urldefense.proofpoint.com/v2/url?u=https-3A__groups.google.com_forum_-23-21forum_xsi-5Flist&d=DwIGaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=l0u6jf5_k23_sUozgc0HB4nfxCjDEMJFBPXUtV-UffI&s=C-Z_EhoqVY9TPNuOSdKA1QKgDk0Lz_-NaBuyp0EqQ3A&e=
 <softimage@listproc.autodesk.com>
Subject: Re: Houdini hierarchical organization

Mmm… if you try (forgive me if I am getting it wrong) to represent data in the 
same way in Houdini you may struggle as it is a different principle.

Only subnetworks can store objects, what lies inside an object is the 
procedural network that is evaluated.

Therefore, if you have a table with four legs, they can be “sons” of a 
subnetwork, but the legs can’t be “sons” of the tabletop. You may pass data 
from one to the other and the behaviour will be similar to that of a hierarchy 
but of course, this is not and therefore won’t be represented as such in the 
Tree View.

In terms of the Tree View limitations, I agree they could bring some ideas from 
XSI into it but let’s not forget, representing a parallel workflow (SOPs for 
example) in a linear hierarchical way is simply not possible. Which is the same 
issue you find in XSI with ICE trees where they are represented by a operator 
in the op stack and you need a special viewer.

I hope I understood well your explanation.
jb

PS. With the guides… I am on it… but the problem is that I am super busy right 
now so finding time is proving very very very difficult.


On 20 Oct 2017, at 20:09, Ponthieux, Joseph G. (LARC-E1A)[LITES II] 
<j.ponthi...@nasa.gov<mailto:j.ponthi...@nasa.gov>> wrote:

Jordi,

Yes, I agree, it is a hierarchy, but the issue is the type of hierarchy it is.

The hierarchy that the Tree View presents is neither procedural nor spatial, 
but rather resembles that of a file system. The word I used earlier was 
“container view”. Tree View appears to be, for lack of a better description, 
more appropriately a “Path View” like Windows Explorer where it reflects the 
scene relative “file paths” of all objects in the scene. This is reflected in 
your example of the first torus when we use 
/obj/subnet1/subnet2/subnet1/torus_object1/tx to address x translation. This is 
similar to the absolute Dag paths in Maya I suppose, those seen when  when 
using “ls –l”. Though it seems to employ a more absolute context in Houdini 
whereas in XSI or Maya you can address parameters from an object’s relative 
path. The confusion in Houdini, for me at least, seems to be that the hierarchy 
relative an object’s name path appears to be exclusive and different from any 
spatial hierarchy? Or is this just a skewed perspective as a result of studying 
the Tree View?

The subnet example you provided appears to be capable of producing a hierarchy 
separate of  the torus and null, but in the context of the view they would seem 
to be all part of the same hierarchy relative their absolute scene path names. 
The second torus and null would seem to be peers to subnet1 under obj for 
example.  So it doesn’t seem that they are exclusive of the hierarchy at all, 
they’re just not part of an extended hierarchy.

What I wanted to see was not the node path hierarchy but rather the 
articulation hierarchy, or spatial hierarchy, the way either Explorer or 
Outliner present it relative object ownership and spatial parenting. I’m 
learning the spatial hierarchy in Houdini has to be constructed in Network View 
buts its not clear from Network View whether these spatial relationships are 
“hierarchical” or “procedural” since they are being constructed in way that 
appears to be visually procedural, but it’s not clear if this is just an 
abstraction (at Network View::Scene Level) or if it is actually procedural.

For example, the spatial relationships established at Geometry level (Network 
View::Geometry) do appear to be procedural, since piping things into a 
transform node for example can both transform and instance. This is not the 
same behavior at Scene level and at Scene level there appears to be very few 
nodes, if any, that appear to behave procedurally. That is, there appears to be 
very few operators at Network View::Scene level, only objects or generator 
nodes or subnet. I get the feeling that the “procedural” connections made at 
the Network View::Scene level aren’t really procedural at all, but rather only 
objective and/or spatial, though they inherently “look” procedural. This just 
isn’t clear.

If that’s the case, the contextual behavior between Scene level and Geometry 
level provides some degree of confusion because the underlying behavior of each 
doesn’t match the similar visual context they are both using which suggests 
procedural relationship and modification. That’s why I wanted to see a clear 
spatial hierarchy representation, vs a path hierarchy or “procedural 
hierarchy”, so I could determine what was acting procedurally on each other vs 
what was related spatially, or both for that matter.

I guess the primary concern I have is in determining what is the best practice 
for setting up any spatial hierarchies, and for that matter, where can spatial 
hierarchies even be set up and how do they differ from context to context 
(Scene vs Geometry for example). Until a couple days ago I thought all network 
connections in Houdini were actually procedural. I’m now questioning whether 
that is the case or are some of these connections that look procedural, are 
they only abstractions for the sake of establishing spatial hierarchy? If that 
is the case, which ones are abstractions and which ones aren’t? How and what do 
I use to establish an awareness of what is being edited by an operator vs what 
is taking only spatial transformation or spatial governance? Is any spatial 
ownership actually occurring at all in Houdini, like in XSI or Maya, or is my 
current assumption incorrect and are all spatial relationships actually 
procedural but  more similar to constraints? I could see that to be the case at 
the Geometry level but that’s not the way it appears at the Scene level. None 
of this is very clear or I’m just not looking in the right place yet ☺

And yes, “procedural hierarchy” is probably a misnomer. Since in theory a 
procedural tree isn’t supposed to be rank based but rather restricted only by 
IO type. Any node at the bottom should be capable of feeding back to any node 
above it that at a minimum matches or uses its IO classes, so ownership (rank) 
should be irrelevant. I guess that’s why I’m finding the use of a procedural 
tree to establish spatial relationships, which are rank based, to be somewhat 
unnerving and counterintuitive. It seems to go against the whole grain of 
proceduralism. Unless there’s something about the way Houdini is doing this 
that I don’t quite grasp yet?

BTW, your Softimage to Houdini document (all 849 pages of it!) is just 
fantastic! I hope you plan to be doing more with it.

Joey


From: 
softimage-boun...@listproc.autodesk.com<mailto:softimage-boun...@listproc.autodesk.com>
 [mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Jordi Bares
Sent: Thursday, October 19, 2017 6:40 PM
To: Official Softimage Users Mailing List. 
https://urldefense.proofpoint.com/v2/url?u=https-3A__groups.google.com_forum_-23-21forum_xsi-5Flist&d=DwIGaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=l0u6jf5_k23_sUozgc0HB4nfxCjDEMJFBPXUtV-UffI&s=C-Z_EhoqVY9TPNuOSdKA1QKgDk0Lz_-NaBuyp0EqQ3A&e=<https://urldefense.proofpoint.com/v2/url?u=https-3A__groups.google.com_forum_-23-21forum_xsi-5Flist&d=DwMFaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=XlsBp8GvwJkE-NA5nIAdVlrDz2EOY1Ef2EsZ2SKOAVs&s=yBbaZwFkSpwlDDezCPJd4Ta89esTQLLtSVzu95xorBU&e=>
 <softimage@listproc.autodesk.com<mailto:softimage@listproc.autodesk.com>>
Subject: Re: Houdini hierarchical organization

Just to clarify…

Hierarchies are fully represented in the Tree View, the content of an object 
too but of course it is impossible to draw in a hierarchical way something that 
is parallel.

For example, in XSI you have an object (that would be your Houdini Object) and 
the operator stack in a linear fashion (which is your SOPs -with regards to 
geoemtry- and in Houdini is non-linear so you can’t see it the same way). 
Nevertheless you can still see all those SOPs nodes arranged in there.

BUT

When you are in your OBJ and you plug one object to another you are NOT 
building a hierarchy, you are just passing data from one node to another, the 
behaviour in many cases is exactly like a hierarchy, but remember you are just 
passing data.

That is the reason you don’t see it graphed in the Tree View.

Try this

1) Create an torus
2) create a subnetrowk
3) create another one
4) create another one

And now have a look at the TreeView… that IS a hierarchy.


Now try this

1) create a new torus
2) create a null
3) plug the null to the torus so the null affects the SRT data on the torus

Check and you will see that IS NOT a hierarchy although it behaves like one.


I hope that helps
jb




On 19 Oct 2017, at 19:54, Ponthieux, Joseph G. (LARC-E1A)[LITES II] 
<j.ponthi...@nasa.gov<mailto:j.ponthi...@nasa.gov>> wrote:

Olivier,

Yes, that’s what I was looking for. Though it really isn’t Tree View but rather 
Network View in List Mode . Apparently its not possible to make Tree View 
behave the way I was expecting it to. But I guess there is a greater advantage 
to having Tree View and Network View in use simultaneously as long as you 
understand that Tree View is neither procedural nor spatial in its 
representation.

This is useful, and it confirms my initial perception of Tree View. It also 
confirms that reconciling the multiple contexts that Network View apparently 
governs, procedural vs spatial for example, is going to take a bit more effort 
than I originally anticipated.


Thanks

Joey


From: 
softimage-boun...@listproc.autodesk.com<mailto:softimage-boun...@listproc.autodesk.com>
 [mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Olivier Jeannel
Sent: Thursday, October 19, 2017 2:25 PM
To: Official Softimage Users Mailing 
List.https://urldefense.proofpoint.com/v2/url?u=https-3A__groups.google.com_forum_-23-21forum_xsi-5Flist&d=DwIGaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=l0u6jf5_k23_sUozgc0HB4nfxCjDEMJFBPXUtV-UffI&s=C-Z_EhoqVY9TPNuOSdKA1QKgDk0Lz_-NaBuyp0EqQ3A&e=<https://urldefense.proofpoint.com/v2/url?u=https-3A__groups.google.com_forum_-23-21forum_xsi-5Flist&d=DwMFaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=HeGph8Xh5ttXXXkUA1HeWYPBLG2Qmno5epbEQVMdgfg&s=HSr8sPtL0vRAqzlfGZqIuieD_U92SvH8KA-P1XezYi8&e=><softimage@listproc.autodesk.com<mailto:softimage@listproc.autodesk.com>>
Subject: Re: Houdini hierarchical organization

Not sure I understand you well Jopseph, but here a little tutorial with som 
"gem" about the tree view
https://urldefense.proofpoint.com/v2/url?u=https-3A__vimeo.com_233232773&d=DwIGaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=l0u6jf5_k23_sUozgc0HB4nfxCjDEMJFBPXUtV-UffI&s=4j8g3QZH26iQaQ8rBEVt9T3fDwDi6WPymok1Nenl1pU&e=<https://urldefense.proofpoint.com/v2/url?u=https-3A__vimeo.com_233232773&d=DwMFaQ&c=76Q6Tcqc-t2x0ciWn7KFdCiqt6IQ7a_IF9uzNzd_2pA&r=GmX_32eCLYPFLJ529RohsPjjNVwo9P0jVMsrMw7PFsA&m=OKef69kBqPJXx68i4heEfHR30NI_NUub2sbaNk2wwws&s=LxaiEbXJ3vm44MM6t9mv5vJ_ShpJjcEj5uTiecLtIkM&e=>
Apologies if I'm way out of topic.

2017-10-19 20:08 GMT+02:00 Jonathan Moore 
<jonathan.moo...@gmail.com<mailto:jonathan.moo...@gmail.com>>:
Apologies for the rushed response as I'm heading out for an event. However, the 
tree view in Houdini is best viewed simply as an alternative data visualisation 
(best utilised a-z filtering). It's not an organisational view or a place where 
you manipulate data. Transform hierarchies should be created in the Network 
Editor and you can quickly traverse nesting structures via the tree view.

In simple terms the Network Editor is where all major scene manipulations take 
place and the Tree View is provided to aid navigation in complex node 
structures.

At least that's the way I've always worked in Houdini.  ;)

jm

On 19 October 2017 at 16:47, Ponthieux, Joseph G. (LARC-E1A)[LITES II] 
<j.ponthi...@nasa.gov<mailto:j.ponthi...@nasa.gov>> wrote:
Hello folks,

I figured people using Houdini on this list would understand the context of 
this question better, coming from a Softimage background, rather than an 
exclusive Houdini background. I’ve been trying to learn Houdini the past 
several months and I’ve suddenly realized something that has me questioning 
some things that may very well be misconceptions on my part, about the 
interface.

To get right to it, is there a way to make Tree View represent object 
hierarchical parenting relative transform relationship?

I’ve discovered that I can create transform relationships just fine in Network 
View, but that it has also taken some effort to realize what happens in 
Network::Scene is both similar and dissimilar to what happens in 
Network::Geometry and neither is exactly reflected the same way in Tree View.  
A big part of the dissimilarities that I’m starting realize differ on how, and 
when, a network produces transform relationships versus when it permits 
procedural editing of object data.

It seems that Tree View only depicts a kind of “container view” context. Or 
rather, what is “inside” something else as opposed to what is the parented 
relationship by transform or articulation context. Tree View is great for 
finding and selecting something but more or less seems ineffective in setting 
up a hierarchy of objects affected by transformation relationships. I’m finding 
the only place I can do that is in Network View, and that the nature of this 
changes in context somewhat depending upon Network View’s active object 
context, whether its Scene or Geometry for example.

Which gets me to my next question, what and where is the proper way in Houdini 
to set up hierarchical relationships of transform context? (Parenting for 
articulation purposes)

I find I can use nulls or geometry in Network::Scene to do this but then I have 
to use transforms in Network::Geometry to do the same thing. But transforms in 
Network::Geometry also permit instancing of the geometry as well as transform 
relationships and the entire behavior of the network in Geometry seems to 
permit a higher degree of proceduralism than does the one at Network::Scene 
level. While none of this is necessarily problematic, it more fundamentally 
raises the question of “what is best practice?”.

Should Geometry nodes be limited to only creating static objects and 
hierarchical articulations established only at Scene level? If so, what nodes 
are best used for transform hierarchies?

Or is reasonable to arrange structures in Geometry nodes that permit transform 
articulations? The concern here is, of course, would such structures end up 
inadvertently duplicating or instancing geometry where I think I am setting up 
transform articulations instead?

And am I left with the ability to create transform articulation hierarchies 
only in Network View and unable to create articulation hierarchies in Tree View?

All thoughts or suggestions in this regard would be very welcome.

--
Joey Ponthieux

__________________________________________________
Opinions stated here-in are strictly those of the author and do not
represent the opinions of NASA or any other party.



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