[x3d-public] Tiered design for skeleton, skin, coveroids
Don Brutzman
don.brutzman at gmail.com
Wed Nov 12 21:03:34 PST 2025
Thanks Carol, this is great and continues to help confirm everyone's shared
understanding.
Regarding physics, I have split out our list of requirements to show (n)
what we can already do in X3D, and (o) what is deferred as future work from
a specification standpoint, since the basic design is needed first prior to
experimentation.
- 4.2.3 Tiered design for skeleton, skin, coveroids
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/concepts.html#TieredDesign>
n. *Currently available: first-order physics*. Simple user-to-geometry
> collision detection is already available in X3D Collision
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/navigation.html#Collision> node
> and NavigationInfo *avatarSize*
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/navigation.html#NavigationInfo> node
> respectively. Current X3D capabilities also include a variety of means to
> simulate kinematics motion (interpolator nodes, scripting, etc.) and the Rigid
> body physics component
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/rigidBodyPhysics.html>
> .
> o. *Deferred: specification requirements for higher-order physics*. We
> assume that future systems will include dynamics (force and accelerations),
> and inverse kinematics (IK). For the present, we are focused on compatible
> synchronized coherence between coveroid tiers. Such design attempts to be
> compatible with such future work, identifying critical parameters or
> limitations when appropriate. Once such a stable tiered design is
> available, meaningful physics-based examples can be modeled, enabling
> implementation and evaluation of alternatives before attempting to define
> new specification requirements.
all the best, Don
--
X3D Graphics, Maritime Robotics, Distributed Simulation
Relative Motion Consulting https://RelativeMotion.info
On Wed, Nov 12, 2025 at 12:16 PM Carol McDonald <cemd2 at comcast.net> wrote:
> Don- per your request on defining Coveroid, I have consolidate the soft
> physics emails and along with discussions from the Web3D event. Hopefully,
> this is helpful.
>
> Carol
>
> On 11/11/2025 9:30 AM PST Don Brutzman <don.brutzman at gmail.com> wrote:
>
>
> Thanks 1M Joe for these excellent thoughts, and also for a productive
> group dialog yesterday. Our updated design goals from yesterday's weekly
> meeting can be found at
>
> - HAnim architecture draft v2.1, clause 4 Concepts, 4.2.3 Tiered
> design for skeleton, skin, coveroids
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/concepts.html#TieredDesign>
>
> I agree with your reasoning that an author building a coveroid ought to be
> able to use either Shape geometry (as occurs in the Humanoid *skeleton*
> field), a morphable mesh (similar to the Humanoid *skin *field), or
> both. Then add Site nodes to define locations for specific
> functionality, including connection points. This design pattern already
> works for Humanoid... for example
>
> - Joe Skeleton Skin Site Salute Walk
> <https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Skin/JoeSkeletonSkinSiteSaluteWalkIndex.html>
>
> Searching for "coveroid" - the following article is also interesting,
> reinforced by Carol McDonald's multiple contributions.
>
> - IEEE SA - How Can the Internet of Clothing Benefit Our Wellbeing and
> Environment?
> <https://standards.ieee.org/beyond-standards/industry/retail/how-can-the-internet-of-clothing-benefit-our-wellbeing-and-environment/>
> - Innovations in Wearable Technology Allow Brands and Consumers to
> Reimagine The Future of Clothing
> - IEEE Standards Association (SA), 2 SEP 2022
>
> particularly
>
>
> *Four Fundamental Components of the Internet of Clothing*
> IoC is enabling new ways for consumers to interact with and benefit from
> their clothing, as well as creating new ways for brands to reach them. And
> data is at the heart of the ecosystem.
>
>
>
> A white paper from the IEEE SA 3D Body Processing Industry Connections
> (IC) Activity
> <https://standards.ieee.org/industry-connections/3d/bodyprocessing/> outlines
> four interconnected components of the data transfer system – human,
> humanoid, cover, and coveroid:
>
>
>
>
> - The human refers to the actual person who wears the piece of
> clothing or footwear while the humanoid is a digital representation of
> the human, such as measurement data sets, dress forms, mannequins, or
> statues. The humanoid is used in the development of the product and is
> created by manual measurement, 3D body scanning of a human, 3D point cloud
> data (PCD) of a human, algorithms, population data, or any combination of
> these.
>
>
> - The cover is anything that a human wears on or above the skin.
> Covers can be an outfit, multiple layers, or a single garment. When
> creating the product, manufacturers use a coveroid, which is a
> physical or digital representative of a cover. Coveroids can be created
> from physical or virtual measurement data, 3D cover scan data, cover point
> cloud data, visual algorithm, material algorithm, or a combination of these.
>
> The body data comes from humans, such as the body temperature, and then it
> is transferred to the humanoid, coveroid, and cover. These four fundamental
> components work together to form a framework of data sharing within the IoC
> ecosystem.
>
>
> It sure seems like the more we examine these IEEE 3DBP concepts from an
> HAnim specification perspective, the more adaptable and integratable they
> seem. Step by step...
>
> So far we have resisted the creation of a new node in HAnim Architecture,
> finding that most of the needed functionality can be implemented using
> existing HAnim nodes.
>
> Nevertheless, since outer tiers might have single or multiple coveroids,
> defining an HAnim Coveroid node would let us encapsulate needed
> functionality and corresponding metadata in a single package. This can
> also facilitate independent creation of a Coveroid object with later
> attachment to (or disconnection from) a Humanoid object.
>
> Hmmm.... thoughts please:
>
> - Why don't we try to define a Coveroid object, which attempts to meet
> these many requirements, and which can be separately created/shared then
> eventually collected as outer tiers attached to a Humanoid object.
>
> all the best, Don
> --
> X3D Graphics, Maritime Robotics, Distributed Simulation
> Relative Motion Consulting https://RelativeMotion.info
>
> On Mon, Nov 10, 2025 at 10:15 AM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
> > Any more requirements?
>
>
>
> The tiers need subsets for various levels of functionality.
>
> From simple 'costume fitment' garments with few binding points
>
> for coveroid to skeleton, up to a 'purchase fitment' coveroid
>
> with complete enough data for a realistic test/purchase/deliver
>
> process.
>
>
>
> Also, the coveroid may be a collection of Segment geometry
>
> corresponding to the x3d Level 1, or be the x3d Level 2
>
> which includes skeleton-driven skin, and various Displacers.
>
>
>
> The top-level model Coveroid will be as smart, maybe smarter,
>
> than the Humanoid because for physical delivery, it is still the
>
> provider guaranteeing the fit. The Humanoid will have
>
> to provide all the fitting information the Coveroid needs to decide
>
> how to incorporate the Coveroid. Then the Humanoid must
>
> evaluate and accept. Then there is the case where the Humanoid
>
> obtain a certain digital piece and do the fitment using other
>
> personal authorship tools.
>
>
>
> So, seems like there needs to be a common set of requirements
>
> for the Humanoid and the Coveroid, so the both oids can integrate.
>
> So the Humanoid goes in and picks a garment and the store says,
>
> "Sorry, you don't currently include sufficient Sensors and Actuators
>
> to try that on. Can we interest you in a selection from this simpler set,
>
> or can you jaunt to the Upgrade Suite?"
>
>
>
> Thanks and Fun with Coveroids,
>
> Joe
>
>
>
>
>
> On Sun, Nov 9, 2025 at 8:55 PM Don Brutzman <don.brutzman at gmail.com>
> wrote:
>
> Given our recent positive experiences with HAnimHumanoid re-use in X3D,
> have appended an additional design requirement. This seems similarly
> do-able.
>
>
> l. The X3D Architecture implementation of HAnim Architecture allows
> repeatable use of HAnimHumanoid nodes when EXPORT [AS] exposes it from
> one file, and Inline, IMPORT [AS] and then USE retrieve the HAnimHumanoid node
> in another file. Similar mechanisms need to be possible for scalable re-use
> and animation of clothing and coveroid models.
>
>
> all the best, Don
> --
> X3D Graphics, Maritime Robotics, Distributed Simulation
> Relative Motion Consulting https://RelativeMotion.info
>
> On Fri, Nov 7, 2025 at 3:14 PM Don Brutzman <don.brutzman at gmail.com>
> wrote:
>
> Dick and I took a good round turn
> <https://en.wiktionary.org/wiki/Appendix:Glossary_of_U.S._Navy_slang#:~:text=Round%20Turn>
> today on draft HAnim v2.1 spec design considerations for clothing, building
> on the list we reviewed together last Monday.
>
> - HAnim Architecture, draft v2.1, section 4 Concepts, 4.2.3 Tiered
> design for internal organs, skeleton, skin, coveroids
> -
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/concepts.html#TieredDesign
>
> 4.2.3 Tiered design for internal organs, skeleton, skin, coveroids
>
> Editors notes:
>
> - Need to describe overall design for Humanoid to have multiple tiers,
> so that layers of clothing can be added compatibly outside a human body.
> - This tiered approach starts with internal organs and musculature
> (someday when ready), then skeleton, then skin, then coveroids...
> - Conceivably this design will integrate well as a *coveroids* field
> for Humanoid
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/ObjectInterfaces.html#Humanoid>
> object.
>
> Terminology:
>
> - Tier <https://simple.wiktionary.org/wiki/tier> is excellent new term
> to use, since we already have existing definitions for layers and levels.
> - We use the term "coveroids" for the outermost tiers, also for name
> of an ordered array field in Humanoid.
> - We hesitate to use the term "clothing" as a field name because it
> might be too limiting with respect to possible usage (e.g. suit of armor,
> artificial exoskeleton) and also because we need to consider non-human use
> cases.
> - Nevertheless "clothes" and "clothing" remain candidate terminology
> for some cases, e.g. OED definition "clothes are items worn to cover the
> body."
>
> Design goals and requirements include:
>
> 1. Current tiers of interest are skeleton, skin, and coveroids.
> Deferred as candidate future tiers: internal organs, musculature, and
> (potentially) a specific facial model.
> 2. Each tier must be rendered in the correct order, from inside to
> outside.
> 3. It must be possible to independently select which tiers are active
> in the current model.
> 4. Can Joint objects be used as root node for each tier (e.g. layer of
> clothing) or is a new node needed? If possible, for both implementation
> complexity and author understanding, it is preferable to *not* add new
> nodes to the specification.
> 5. How do we handle meshes for coveroids? Similar to skin, authors may
> prefer Segment-based geometry or mesh changes or both. If design ends up
> being sufficiently similar, might we modify and refactor the existing
> *skin* field to be a list of meshes for each of tiers? Alternatively,
> it may be more object-oriented to keep each mesh encapsulated in each
> individual tier.
> 6. To support such an approach for coveroids and other tiers, might we
> add *visible* field to Joint
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/ObjectInterfaces.html#Joint>
> and Segment
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/ObjectInterfaces.html#Segment> objects,
> in order to facilitate making blocks of geometry (and all related children)
> nonvisible and inactive? Correspondingly ought we create a boolean array
> for visibility in Humanoid object? (A similar approach using a boolean
> array already exists for Motion node, however note that when implemented in
> X3D that requires authors to use scripting and is awkward to control at run
> time.)
> 7. If a particular tier has no geometry, or is not visible, then it is
> not active.
> 8. What are requirements for definition of connections between tiers
> (for example, layers of clothing connections to skin/skeleton)? Such
> connectivity almost certainly must link (directly or indirectly) to
> skeleton in order to maintain coherent animation of the humanoid. The
> Site object is an obvious candidate for defining such connectivity.
> 9. Can Site object be applied consistently in context of each of the
> tiers? In other words, is a point-wise approach using Site sufficient, or
> might other kinds of connections be necessary? It is likely possible but
> careful definitions are needed since non-point connections (line or
> surfaces) might be needed. (For example, is the shoulder line for clothing
> represented by a set of points or a line?)
> 10. Need ability to attach or detach connections (for example, when a
> humanoid is putting on or taking off a hat).
> 11. Test case: is fur part of skin or part of coveroids? (Such design
> is probably an author option, who might also choose to paint segment
> geometry.)
> 12. Any more requirements?
>
> Group conversations are definitely helping, and comments are always
> welcome.
>
> This approach has potential to only require addition of a *coveroids* field
> to the *Humanoid*
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/ObjectInterfaces.html#Humanoid>
> object, which is interesting simplicity. Also addition of *visible *field
> to Joint
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/ObjectInterfaces.html#Joint>
> and Segment
> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/ObjectInterfaces.html#Segment> objects
> offers appealing usefulness from a regular HAnim perspective, the ability
> to hide limbs or portions of the body... Things look a little better each
> time.
>
> Once we are all reasonable happy with these requirements, suggested next
> steps are:
>
> - define a few simple use cases that describe expected functionality,
> later looking at MSF use cases.
> - start converting design requirements into specification prose,
> - building a simple example.
>
> Have fun thinking about future Humanoids wearing clothes! 👔👕👖👗👘👙👚🥼
>
> p.s. for Carol: and shoes too! 👡👢🥾🩴👞👟👠🥿🩰
>
> all the best, Don
> --
> X3D Graphics, Maritime Robotics, Distributed Simulation
> Relative Motion Consulting https://RelativeMotion.info
>
>
>
>
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