[x3d-public] Euler rotation

Mon Jan 7 02:03:37 PST 2019

Hi Joseph,

Thank you for your reply. Just to be sure: the context I meant to discuss is about having a convenient attribute in the declarative syntax, say 'euler', to set the initial orientation of the transform, so anyone can use either 'rotation' or 'euler'.

<transform euler="20 40 10" >

So I interpreted Vince's $yaw, $pitch and $roll to be just placeholders, for manual substitution.

You are right using this with either radians or degrees would be equally simple.

Regards,

Albert Jan

From: Joseph D Williams<mailto:joedwil at earthlink.net>
Sent: Sunday, January 6, 2019 7:20 PM
To: Albert Jan Wonnink<mailto:awonnink at hotmail.com>; vmarchetti at kshell.com<mailto:vmarchetti at kshell.com>; X3D-Public<mailto:x3d-public at web3d.org>
Subject: Re: [x3d-public] Euler rotation

Hi Albert and All,

When you use euler (or Tait-Bryan) angles for a while you will find that you get problems.

Actually there is plenty of writing about the details maybe even in the x3d or hanim archives and widely on the web.

In addition, when you create or edit the things much then you will find it is actually a lot easier to use quats or axis-angle radians. In general, for degrees, maybe your editing system may offer as a learning tool if radian is really an elementary block to learning, but really, never in the user code due to misleading simplicity and what ‘cha finally gonna tell ‘em when the gimbals lock?

  *   <Transform DEF="yaw-rotation" rotation="0 0 1 $yaw">
  *   <Transform DEF="pitch-rotation" rotation="0 1 0 $pitch">
  *   <Transform DEF="roll-rotation" rotation="1 0 0 $roll">

Besides the fact that a variable is not allowed there

(maybe use a prototype if you need a variable?)

I don't think your naming of yaw and pitch and roll is reasonable for x3d.

For default transform rotation 0 0 1 0, sit on it and face +z and find +y is up and +x is left.

then fly the thing using pitch and yaw and roll.

The x3d axis-angle parameters are most likely pitch yaw roll then the scale,

and I think the same order for quaternions, except where the 'scale' is placed and the special limits for values.

Why not try the following:

DEF Pitch OrientationInterpolator {

key [ 0, 0.25 0.5, 0.75 1 ]

keyValue [ 0 0 1 0, 1 0 0 1.5, 0 0 1 0, -1 0 0 1.5, 0 0 1 0 ] }

DEF Yaw OrientationInterpolator { key [ 0, 0.25 0.5, 0.75 1 ]

keyValue [ 0 0 1 0, 0 1 0 1.5, 0 0 1 0, 0 -1 0 1.5, 0 0 1 0 ] }

DEF Roll OrientationInterpolator {

key [ 0, 0.25 0.5, 0.75 1 ]

keyValue [ 0 0 1 0, 0 0 1 1.5, 0 0 1 0, 0 0 1 1.5, 0 0 1 0 ] }

Thanks and Best,

Joe

From: Albert Jan Wonnink<mailto:awonnink at hotmail.com>
Sent: Sunday, January 6, 2019 2:25 PM
To: vmarchetti at kshell.com<mailto:vmarchetti at kshell.com>; X3D-Public<mailto:x3d-public at web3d.org>
Subject: Re: [x3d-public] Euler rotation

Thanks Vince, for your reply.

As long as the angles and X3D code is  generated by code one can of course easily calculate the individual parameters for a quaternion. But during the testing of our experimental Unity based browser, and preparing scenes for that, I found it very easy to extend the transform specification with a degree-based Euler attribute (Tait-Bryan would also have worked).

The current system still makes it relatively difficult to manually apply an angle of the most used fractions of PI, doesn't it?

I guess this issue must have been discussed in one of the early days of the X3D specification. But it seems to me a lost chance to make it more convenient.

Regards

Albert Jan Wonnink

Van: vmarchetti at kshell.com <vmarchetti at kshell.com>
Verzonden: zondag 6 januari 2019 22:49
Aan: Albert Jan Wonnink; X3D-Public
Onderwerp: Re: [x3d-public] Euler rotation

There is no single node Euler angle alternative representation of a rotation transform defined in the current (v 3.3) X3D standard.

You can get an easier to edit representation of Euler angle rotation (specifically the Tait-Bryan angles, https://en.wikipedia.org/wiki/Euler_angles#Tait%E2%80%93Bryan_angles<https://en.wikipedia.org/wiki/Euler_angles#Tait–Bryan_angles>, commonly used for vehicle oriented

with respect to the horizon, by nesting 3 Transforms:

<Transform DEF="yaw-rotation" rotation="0 0 1 $yaw">

<Transform DEF="pitch-rotation" rotation="0 1 0 $pitch">

<Transform DEF="roll-rotation" rotation="1 0 0 $roll">

<!-- put vehicle model here -->

<Shape>...</Shape>

</Transform>

</Transform>

</Transform>

where for $yaw, $pitch, $roll you need to substitute the numerical value of the rotation angle in radians.

Vince Marchetti

On Jan 6, 2019, at 12:53 PM, Albert Jan Wonnink <awonnink at hotmail.com<mailto:awonnink at hotmail.com>> wrote:

Is there, or should there be, an Euler alternative for the transform 'rotation' property? This makes direct x3d code editing much easier.

Regards,

Albert Jan Wonnink

_______________________________________________
x3d-public mailing list
x3d-public at web3d.org<mailto:x3d-public at web3d.org>
http://web3d.org/mailman/listinfo/x3d-public_web3d.org

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20190107/1789254c/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 9B68D1D68F1247D1A07F4C368D0D7215.png
Type: image/png
Size: 156 bytes
Desc: 9B68D1D68F1247D1A07F4C368D0D7215.png
URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20190107/1789254c/attachment-0001.png>