[x3d-public] Player inconsistency > CylinderSensor > interpretation of local vs sensor-local

[Andreas Plesch]

On Sun, Dec 3, 2017 at 5:17 PM, Andreas Plesch <andreasplesch at gmail.com> wrote:
>>
>> Date: Sun, 3 Dec 2017 18:02:47 +0000
>> From: doug sanden <highaspirations at hotmail.com>
>> To: "x3d-public at web3d.org" <x3d-public at web3d.org>
>> Subject: [x3d-public] Player inconsistency > CylinderSensor >
>>         interpretation of local vs sensor-local
>> Message-ID:
>>         <MWHPR1401MB1982C8C77F571F605CDE02DBB63F0 at MWHPR1401MB1982.namprd14.prod.outlook.com>
>>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> I noticed a bit of inconsistency among players when axisRotation is non-default.
>> I wonder what's right.
>> -Doug
>>
>> http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/pointingsensor.html#CylinderSensor
>> """
>> ... pointer motion (e.g., a mouse or wand) into a rotation on an invisible cylinder that is aligned with the Y-axis of the local sensor coordinate system. The local sensor coordinate system is created by applying the axisRotation field value to the local coordinate system.
>> ...
>> rotation_changed event is sent that equals the sum of the rotation about the +Y-axis vector of the local sensor coordinate system
>> ...
>> trackPoint_changed events reflect the unclamped drag position on the surface of the invisible cylinder. [Q, in local or sensor-local?]
>> """
>> Q, Does that mean we should
>> - rotate the invisible sensor geometry by axisRotation
>> - leave rotation_changed in sensor-local
>> - put trackpoint_changed  into local coordinates (not sensor-local)?
>>
>> more..
>>
>> http://dug9.users.sourceforge.net/web3d/tests/sensors/CylinderSensorCylinderAxisRotation90.x3d
>> (http://dug9.users.sourceforge.net/web3d/tests/sensors/CylinderSensorCylinder.x3d default axisRotation)
>> http://dug9.users.sourceforge.net/web3d/tests/sensors/cobweb90.html
>> routing:
>> - box is rotated by rotation_changed
>> - little sphere is translated by trackpoint_changed
>>
>> player:         rotates:
>> octaga - sensor-geometry, rotation_changed, trackpoint_changed
>> instant - sensor-geometry, rotation_changed, trackpoint_changed moves diagonally
>> H3D     - sensor-goemetry, rotation_changed
>> vivaty - nil
>> view3dscene - sensor-geometry, trackpoint_changed
>> freewrl - sensor-geometry
>> cobweb - sensor-geometry, rotation_changed
>>
>
>
> Two more players:
> BS Contact: does not rotate rotation_changed, little sphere stays with dragging mouse pointer

Ok, on a 2014 version the console has an error message that the
axisRotation field value could not be set. So no surprise that it had
no effect.

>
> x3dom:  does not rotate rotation_changed, does not translate little sphere (no trackpoint_changed event?)

I looked into the implementation. I believe it would be
straightforward to apply the axisRotation rotation to the
rotation_changed output.

>
> https://bl.ocks.org/andreasplesch/34d6c24972d37a0ad9e2070cf3a8a2c6
>
> Focusing on rotation_changed as the principal node output we then have:
>
> Octaga, Instant, H3D, cobweb : rotate by axisRotation
> BS, x3dom, view3dscene, freewrl: do not rotate by axisRotation
>
> 4:4, a perfect split (!).
>
> To me the intended function of the axisRotation field is to control the direction of the rotation output such that rotations other than about the Y axis become available. If that is the case then the rotation_changed output should be affected by the axisRotation field, eg. be rotated.
>
> A related question is if the axisRotation field is intended to provide functionality which cannot be achieved by wrapping the Sensor in a Transform with the same rotation value which would also result in a rotated sensor local coordinate system. Presumably the answer is yes in order to justify its existence but I am not sure.
>
> For reference, here are the conformance scenes but they do not seem to include non-default axisRotation sensors:
>
> http://www.web3d.org/x3d/content/examples/ConformanceNist/Sensors/CylinderSensor/index.html
>
> Perhaps axisRotation was introduced relatively later ?

It looks the field was introduced in 2008 with v 3.2 since 3.1 and 3.0
do not seem to have it ? So there should be some discussion somewhere
?

>
> -Andreas
>
> --
> Andreas Plesch
> Waltham, MA 02453




-- 
Andreas Plesch
Waltham, MA 02453