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

[John Carlson]

I’ve not had success with Blender Bvh import.

John

On Sat, Oct 14, 2023 at 6:54 AM GPU Group <gpugroup at gmail.com> wrote:

> 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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