[x3d-public] PlaneSensor behavior, was: [x3dom-users] port this example to X3DOM?

Michalis Kamburelis michalis.kambi at gmail.com
Thu Jun 1 14:43:53 PDT 2017


2017-06-01 21:40 GMT+02:00 Andreas Plesch <andreasplesch at gmail.com>:
> Cobweb and perhaps other x3d browser do not require this offset value for
> expected behaviour. This now raises the question which interpretation of
> PlaneSensor is correct, eg. should the offset here be necessary ?
>
> http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/pointingsensor.html#PlaneSensor
>
> says:
>
> '..a translation_changed event is output which corresponds to the sum of the
> relative translation from the original intersection point to the
> intersection point of the new bearing in the plane plus the offset value.'
>
> As a relative translation I would interprete this language to mean that
> translation_changed starts out with '0 0 0' and then accumulates from there.
> In the example, translation_changed is routed to an transform with an
> initial translation value of '1 -1 .01' which means that a '0 0 0'
> translation would lead to the previously observed initial jump. Adding an
> offset therefore seems necessary. So x3dom behaviour seems correct ?
> Generally cobweb is more strict in following the spec, so I am little
> surprised.
>

At least view3dscene also requires this offset, as I understood the
specification in the same way as you. Without the offset, the green
ball indeed will "jump" at the first drag to (0,0,0). With the offset,
it's OK.

I tested on x3d extracted from your
https://glitch.com/edit/#!/jade-aluminum?path=views/index.html:34:0 .

Regards,
Michalis
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