[x3d-public] Units for BVH vs HAnimMotion.values

[GPU Group]

The Blender > Export/Import > mocap bvh code may have some hints.
Hypothesis: on import it converts from mocap to interpolators, on export
goes the other way.

Q. do you think that HAnim 5.2.4 Angle Conversion Procedure is sufficient
to imply Motion data is in degrees? It doesn't mention the Motion node
explicitly (Hypothesis written in an early era).. If so we could make the
Motion.values degrees by default, as Joe suggested and 5.2.4 'indirectly
implies'?
-Doug


On Sat, Oct 14, 2023 at 2:47 AM John Carlson <yottzumm at gmail.com> wrote:

> Here's the Euler Angle to Axis-Angle in HAnim Pt section 5.2.4
>
>
> https://www.web3d.org/documents/specifications/19774/V2.0/MotionDataAnimation/AnimationUsingInterpolators.html#AngleConversionProcedure
>
> Hmm!  I'm guessing that Blender has a routine for this! Sure enough!
> Trying it now.
>
> Not with HAnimMotion, I don't know how to do that yet.  Suggestions?
>
> John
>
> On Sat, Oct 14, 2023 at 12:21 AM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
>> > Um, then why is angle even listed here?
>>
>>
>>
>> That is easy, take another look.
>>
>> Euler angles are not listed anywhere!
>>
>> Convert to axis-angle like showed in Part 2 and forget xyz angles/
>>
>> Joe
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: John Carlson <yottzumm at gmail.com>
>> Sent: Oct 13, 2023 6:15 PM
>> To: Joe D Williams <joedwil at earthlink.net>
>> Cc: <x3d-public at web3d.org>
>> Subject: Re: [x3d-public] Units for BVH vs HAnimMotion.values
>>
>>
>> Um, then why is angle even listed here?
>>
>> Confusing as heck!
>>
>>
>> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/concepts.html#t-Standardunits
>>
>> John
>>
>>
>> On Fri, Oct 13, 2023 at 7:19 PM Joe D Williams <joedwil at earthlink.net>
>> wrote:
>>
>>> > otherwise specified in a UNIT statement
>>>
>>>
>>>
>>>
>>> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/concepts.html#Standardunitscoordinates
>>>
>>>
>>>
>>> "However, the world coordinate units may be modified by specifying a
>>> different length unit using the UNIT statement."
>>>
>>>
>>>
>>> There is Not Now nor will there Ever be a UNIT statement that allows
>>> degrees for rotation and orientation.
>>>
>>>
>>>
>>> Never, will angles appear in any x3d animation interpolator.
>>>
>>> To apply an import using angle units, it is converted to x3d before use,
>>> then discarded or possibly stored somewhere away from working area for
>>> reference.
>>>
>>>
>>>
>>> Thanks and Best,
>>>
>>> Joe
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: John Carlson <yottzumm at gmail.com>
>>> Sent: Oct 13, 2023 11:44 AM
>>> To: X3D Graphics public mailing list <x3d-public at web3d.org>
>>> Subject: [x3d-public] Units for BVH vs HAnimMotion.values
>>>
>>>
>>> Apparently BVH uses degrees for rotations.  Units for HAnimMotion should
>>> use radians unless otherwise specified in a UNIT statement, AFAIK.
>>>
>>> Comments?
>>>
>>> Thanks!
>>>
>>> John
>>>
>>>
>>>
>>
>>
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