[X3D-Ecosystem] Geometry nodes in Blender.

[John Carlson]

Thanks for your time.

On Fri, Dec 20, 2024 at 3:01 PM Michalis Kamburelis <
michalis.kambi at gmail.com> wrote:

> I'm sorry, I just personally don't have more resources (time) to help
> in this thread. I'm afraid I don't have time to investigate particular
> input / output you use. I was just trying to advise and clear up some
> (seemingly) confused statements about Blender. It is getting harder
> and harder to address everything as this thread goes on :)




>
> I would advise in general to just learn Blender and use it for a while
> as a regular 3D artist / animator does (or consult with a 3D artist
> what you do -- there's a huge Blender community/communities, someone
> may help you if you ask on Blender forums/stackoverflow). Blender is
> used in an enormous amount of professional 3D modeling and animating
> (it has much more usage, and for more time, than both X3D/H-Anim and
> glTF combined :) ), so I'm sure it's up to whatever task you need.
> Learning Blender is a necessary first step to import/export things
> into Blender in a natural way. You don't need to become an artist, but
> you need to learn to achieve what you need by "clicking" to understand
> what the artists are doing.


I would rather do something besides Blender, at this point.

>
>
> - And of course please don't fork Blender :), as this seems like an
> overkill for a task you want to do.
>
> - As I said, I don't know if Blender supports "center" for
> transformations or not. I did not need it, and I don't consider it
> that critical (glTF transformations also don't have it). If it does
> not, then you have a clear option how to work around it -> just add an
> intermediate joint that does a shift.


Center is plainly in the EditBone and PoseBone python API.  Center is
readonly.  It’s not a joint center, it’s halfway between head and tail.
Per the documentation.

>
>
> - As for attaching objects as children of bones (when you don't want
> to use skinned animation for some objects, just a rigid object that
> follows transformation of some joint), please search the documentation
> and/or watch videos how to do this. You basically need to press Ctrl+P
> once proper bone and object are selected in proper mode. This is
> surely possible, I used it a lot.


I’ve done multiple searches, watched videos, spent months trying
alternatives.  Feel free to send a python log.  I don’t require it though.
I’m waiting for a Dell representative.

>
>
> - I don't understand when John says he cannot find "joints" in Blender


Because I don’t think joints have a head and a tail.   Bones do.  If joints
have a head and a tail.

>
> (they are just called bones), or why weights seem weird (each bone has
> weights, expressed as a vertex group; "vertex group" is a general
> concept in Blender to assign "named weights", using them for bones is
> just one application). Just use "Weight Painting" to explicitly
> see/modify these weights. Follow the documentation about bones and
> weight painting (
> https://docs.blender.org/manual/en/latest/animation/index.html ) or a
> number of YouTube videos. If you found a problem in Blender
> documentation, please submit it as a Blender bug and/or ask in Blender
> community.


There’s no problem with Blender or X3D alone.  I’m guessing putting them
together has been tried before.  I’m just the dummy that tried it again.

>
>
> Regards,
> Michalis
>
>
> pt., 20 gru 2024 o 21:16 John Carlson <yottzumm at gmail.com> napisał(a):
> >
> > Here's the export as .glb.  Comments are welcome!
> >
> > John
> >
> > On Fri, Dec 20, 2024 at 12:06 PM Joe D Williams <joedwil at earthlink.net>
> wrote:
> >>
> >> Please look at John's export of joekick from blender. The skin binding
> works fine except that it also includes all other geometry in the file as
> skin so it  doesn't work quite right.
> >> The problem in the exported file is that the 'standard' blender
> transform node does not know about "center" and so it has to be added by a
> silly USEage in blender to work.
> >> Just fix blender (1) so it knows about center in a 'standard'
> Transform, and (2) how it seems to include all geometry in the file, even
> children of joints, as included in"skin" field and most all will be fixed.
> >>
> >> The idea of a bone center is not useful unless it is a joint. If a
> center field is mentioned anywhere in blender it is in relation to a begin
> bone end as some sort of crutch for having left center out of standard
> Transform. Recall the days in 1998 when some tool makers were saying nah,
> we don't need center in our transform object, translation, rotation, and
> scale is plenty to expose except as special usage.
> >> Thanks,
> >> Joe
> >>
> >>  .
> >> -----Original Message-----
> >> From: Michalis Kamburelis <michalis.kambi at gmail.com>
> >> Sent: Dec 20, 2024 2:07 AM
> >> To: John Carlson <yottzumm at gmail.com>
> >> Cc: X3D Ecosystem public discussion <x3d-ecosystem at web3d.org>, Vincent
> Marchetti <vmarchetti at kshell.com>, Katy Schildmeyer KS APPAREL DESIGN <
> katy at ksappareldesign.com>, Carol McDonald <cemd2 at comcast.net>, Joe D
> Williams <joedwil at earthlink.net>
> >> Subject: Re: Geometry nodes in Blender.
> >>
> >> > I think what you're saying is break a bone into 2 pieces, one with
> head plus center (now tail) and one with center (now head) plus tail. This
> seems like an excellent idea. I'm going to think on it a bit.
> >> > My question is, what do I name the 2 pieces? I'm guessing something
> that I can combine on export.
> >>
> >> Indeed.
> >>
> >> As for new bone names: "Leg1_center" (when you need to add new Blender
> >> bone when "Leg1" joint has non-zero center in X3D/H-Anim) would look
> >> reasonable for me (and code can figure out what happened and invert
> >> it, so you can have round-trip that later exports it back into one
> >> "Leg1" joint with non-zero center). But that's just a suggestion.
> >>
> >> > This sounds like Zeno's paradox where I'm just trying to put weights
> where they don't go. The weights go on the joints. We only have weights for
> joints on import. ((well, I don't know all of X3D).
> >>
> >> Weights describe how much each joint influences each vertex. This is
> >> equal in Blender, X3D/H-Anim, glTF.
> >>
> >> I'm not sure if what you're saying is equivalent, but if yes -> OK :)
> >>
> >> > Remember I'm doing this in python, not in the Blender GUI.
> >>
> >> Sure, but it should be similar. That is, Blender's Python API exposes
> >> a superset of things that you can do from GUI and it uses the same
> >> terminology, mostly. And you can observe in Blender's console what
> >> your interactive operation "means" in Python, it's a valid way to
> >> learn Blender's Python API.
> >>
> >> > It sounds like I should give up on ever trying to import site or
> segment geometry, and *try* to do Joints and skin.
> >>
> >> I'm not sure what do you mean here :)
> >>
> >> The H-Anim "skin" (one mesh, with joints and weights) should map to
> >> Blender, because it is exactly the same concept in Blender. (OK, not
> >> *exactly* the same, e.g. Blender, because of history, calls "bones"
> >> what X3D/H-Anim and glTF call "joints"; but it is close to equivalent,
> >> for 3D graphic artists these are the same things).
> >>
> >> You don't need to "give up" on anything, from what I can see. Just
> >> import/export X3D/H-Anim skin to Blender's skin (Armature). This is
> >> what 3D artists would expect.
> >>
> >> Other features (like attaching rigid objects to sites, without skin)
> >> are a separate thing. They can be imported/exported e.g. as bones'
> >> children. But these are separate things, I'd advise to focus on the
> >> hard case (skin) first :)
> >>
> >> Regards,
> >> Michalis
> >>
> >>
>
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