[X3D-Ecosystem] Geometry nodes in Blender.

[John Carlson]

*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.*

*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).*

*Remember I'm doing this in python, not in the Blender GUI.*


*It sounds like I should give up on ever trying to import site or segment
geometry, and *try* to do Joints and skin.*



*Thanks,*
*John*

On Fri, Dec 20, 2024 at 2:09 AM Michalis Kamburelis <
michalis.kambi at gmail.com> wrote:

> > Right now, It looks like I can attach a vertex_group to a Hook Modifier
> (?) for skin weights on at least Blender objects.  But all of this
> information is from AI.
>
> In general: don't trust AI suggestions for such high-level problems.
> The sentence above is somewhat correct, but it's not leading you
> toward a solution that makes sense, IMHO.
>
> To be clear,
>
> - Yes -> there are vertex groups and hook modifier in Blender (you can
> search Internet and Blender docs to understand what they do).
>
> - But importing regular H-Anim skinned animation -> into hook
> modifiers (which, I understand, you wonder about) does seem like an
> overkill.
>
>     It would be quite unexpected transition for someone who knows both
> Blender and X3D. You really should import H-Anim skinned animation
> (using H-Anim joints) into Blender skinned animation (using Blender
> bones). These are directly, or mostly, equivalent. I would expect one
> is imported into another, without adding hook modifier.
>
>     If the Blender don't have a concept of "center", then
>
>     - Look hard does it really not have it.
>     - If center is non-zero, introduce dummy bones to account for the
> translation caused by "center". It's an additional complication, but
> IMHO it will be much simpler (and generate less surprising results)
> than changing skinned animation into hook modifiers :)
>
> Regards,
> Michalis
>
> pt., 20 gru 2024 o 08:01 John Carlson <yottzumm at gmail.com> napisał(a):
> >
> > Thanks for information, Michalis.
> >
> > What we're trying to do is figure out Import/Export for HAnim.  There's
> an argument about bone center versus joint center.  Obviously, for EditBone
> and PoseBone centers, they can't be set on import.  If we can't set centers
> I don't think we should export bone centers.   Instead, we could take the
> approach that bone head or tail is exported.  This isn't perfect.  I'm
> hoping to use a non-Bone alternative.  Right now, It looks like I can
> attach a vertex_group to a Hook Modifier (?) for skin weights on at least
> Blender objects.  But all of this information is from AI.
> >
> > If someone knows how to use Rigify to create the equivalent of an
> Armature for modern Blender, Please record your Blender session.  But I
> think I may already have one.
> >
> > John
> >
> > On Fri, Dec 20, 2024 at 12:45 AM Michalis Kamburelis <
> michalis.kambi at gmail.com> wrote:
> >>
> >> There's a lot of documentation and videos about Blender Geometry
> >> nodes, you're welcome to read/watch them to learn what they do :)
> >>
> https://docs.blender.org/manual/en/latest/modeling/geometry_nodes/introduction.html
> >> . Geometry nodes are more flexible approach to the concept of
> >> "Modifiers stack" in Blender: output geometry is computed from input
> >> following user-defined operations.
> >>
> >> As for import / export, there's nothing new we should do.
> >>
> >> - For export: "Geometry nodes" is a Blender modifier. We already allow
> >> users to "Apply Modifies" when exporting (both X3D and glTF exporter
> >> have a suitable checkbox). That's all we can and should do.
> >>
> >> - There's no "import of Geometry nodes", because other formats (like
> >> glTF or X3D) don't have anything like this.
> >>
> >> Regards,
> >> Michalis
> >>
> >> pt., 20 gru 2024 o 02:48 John Carlson <yottzumm at gmail.com> napisał(a):
> >> >
> >> > Hey, guys.
> >> >
> >> > It looks like there are Geometry nodes in Blender, but I’m pretty
> clueless on how to export or import them.
> >> >
> >> > If someone has some files with geometry nodes that I can practice
> with, that would be great.
> >> >
> >> > Also, how the heck do I get the Geometry node view?
> >> >
> >> > Time to watch some videos, I guess.
> >> >
> >> > John
>
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