[UsdSkel Docs] A few issues / inconsistencies

[rlei-weta]

Description of Issue

The </Model/Arm> Mesh prim in the "Skinning an Arm" example is missing an applied UsdSkelBindingAPI.

Steps to Reproduce

1. Open usdview with the skinning an arm example.
2. See the following deprecation warnings:

Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointIndices>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply)
Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointWeights>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply)
Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:geomBindTransform>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply)
Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointIndices>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply)
Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointWeights>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply)
Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:geomBindTransform>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply)

Package Versions

20.11

[rlei-weta]

Small nitpick of the UsdSkelBindingAPI's primvars:skel:geomBindTransform doc:
"Encodes the bind-time world space transforms of the prim..."
Should be singular "transform".

[rlei-weta]

In this section:
https://graphics.pixar.com/usd/docs/api/_usd_skel__schemas.html#UsdSkel_SkelAnimation_Binding

Should </Model/Anim> mentioned in:

... will be affected by the SkelAnimation at </Model/Anim>.

be </Anim> instead?

[rlei-weta]

Was also hoping get some clarification in this section:
https://graphics.pixar.com/usd/docs/api/_usd_skel__intro.html#UsdSkel_TransformSpaces

Where the parentJointSkelSpaceTransform is an identity matrix for root joints, or ...

Is skeleton space the object space of the Skeleton prim itself? If so, couldn't root joints (especially in the case of multiple root joints) have a non-identity skeleton space transform?

.. Or - is skeleton space referring to the object space of individual, per-root skeletal hierarchies encoded by the Skeleton prim - in which the quoted sentence makes sense!

[spiffmon]

Thanks, Richard - we thought we’d updated everything, but must have missed this example!

On Fri, Oct 23, 2020 at 12:20 AM Richard Lei ***@***.***> wrote: Description of Issue The </Model/Arm> Mesh prim in the "Skinning an Arm" example <https://graphics.pixar.com/usd/docs/api/_usd_skel__schema_overview.html#UsdSkel_SchemaOverview_SkinningAnArm> is missing an applied UsdSkelBindingAPI. Steps to Reproduce 1. Open usdview with the skinning an arm example. 2. See the following deprecation warnings: Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointIndices>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply) Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointWeights>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply) Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:geomBindTransform>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply) Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointIndices>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply) Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:jointWeights>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply) Warning: in _DeprecatedBindingCheck at line 200 of /code/USD/pxr/usd/usdSkel/cacheImpl.cpp -- Found binding property </Model/Arm.primvars:skel:geomBindTransform>, but the SkelBindingAPI was not applied on the owning prim. In the future, binding properties will be ignored unless the SkelBindingAPI is applied (see UsdSkelBindingAPI::Apply) Package Versions 20.11 — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1370>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABPOU2H5GYBI345ZAYYDQQLSMEVC5ANCNFSM4S4FXXGQ> .

-- --spiffiPhone

[rlei-weta]

Cheers @spiffmon

One more for you guys 😛
https://graphics.pixar.com/usd/docs/api/_usd_skel__schemas.html#UsdSkel_BlendShape_Inbetweens

In-between shapes can be created via UsdSkelBlend::CreateInbetween(),

Looks like it should be UsdSkelBlendShape::CreateInbetween()

[jilliene]

Filed as internal issue #USD-6448

[MikeWise2718]

I would like to know how to remove the warning, but it is not clear to me what a "missing applied UsdSkelBindingAPI" statement actually looks like. I have a huge number of these warnings, and found the example in the repo, but was dismayed to see that it has the same issue, and it is an open issue for over a year.

I don't need actually need the examplet fixed, but could someone tell me what I need to add to the file to suppress the warning?

It seems the "bindingAPI" was changed to "SkelBindingApi", but I don't see anything that looks like a statement that effect in the example or in the generated file I am working with.

[spiffmon]

Hi @MikeWise2718 , and apologies, UsdSkel has been a little neglected for awhile. We will get this ticket resolved soon. But to your question:
a) You can look at the UsdSkelExamples downloadable from our website, which is properly formed.
b) Any prim that has UsdSkel data authored via the UsdSkelBindingsAPI, which will likely be every Mesh/Gprim, plus the prims at which you have bound a Skeleton or Animation, must have the SkelBindingAPI applied. In usda, it will look something like this:

def "HumanFemale_Group" (
    prepend apiSchemas = ["SkelBindingAPI"]
    prepend references = @./HumanFemale.usd@
)
{
    rel skel:animationSource = </HumanFemale_Group/SkelAnim>
    # etc.
}

The very easy way to ensure this, which is a general rule for working with applied API schemas, is that at any codesite at which you are using SkelBindingAPI to author data, create the schema object by calling bindingAPI = UsdSKel.BindingAPI.Apply(prim) rather than just using the schema constructor. This will ensure that the schema gets added to the apiSchemas metadata, and it's fine if two different, overlapping layers both apply it.

Does that give you what you need?

[MikeWise2718]

Yeah, that helps a lot. In my case I only had to add the prepend apiSchemas part to the Mesh prims that were under my SkelRoot prim. I have a script that fixes up output from the buggy Unity USD exporter so this meets my needs. But I will report it on as a bug to the Unity USD github project too and reference this to help them to fix it at the root cause.

[gitamohr]

You are a paragon of your surname, my good sir!

…

On Sun, Dec 19, 2021 at 4:01 AM Mike Wise ***@***.***> wrote: Yeah, that helps a lot. In my case I only had to add the prepend apiSchemas part to the Mesh prims that were under my SkelRoot prim. I have a script that fixes up output from the buggy Unity USD exporter so this meets my needs. But I will report it on as a bug to the Unity USD github project too and reference this to help them to fix it at the root cause. — Reply to this email directly, view it on GitHub <#1370 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABWBQALJJFMJD6WYWAUK74LURXCRHANCNFSM4S4FXXGQ> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>