# Re: [round-display] [motion-path] Orientation of elements due to merging polar positioning and motion path

Date: Wed, 18 May 2016 03:11:08 +0000
Message-ID: <CAGTfzwR5Rj6Xv8E2XAWZmzBhz-tfrEpMZi0ZusMj9RwzQQ2pTA@mail.gmail.com>
```On Wed, May 18, 2016 at 11:51 AM fantasai <fantasai.lists@inkedblade.net>
wrote:

> On 05/17/2016 03:01 PM, Shane Stephens wrote:
> >
> > motion-rotation: auto;
> > translate: 100px;
> > rotate: 20deg;
> >
> > and
> >
> > motion-rotation: auto 20deg;
> > translate: 100px;
> >
> > will produce different results. The former will move the object 100px in
> front of the path (in the current direction of the
> > path) then rotate the object by 20deg, whereas the latter will rotate it
> by 20deg (off the current direction of the path) then
> > move it 100px in its new heading.
>
> Wait, really? That seems very confusing to me. I would have
> thought that the motion-* and rotate-* were all independent
> and 'translate' operated on top of that result.
>

You need to specify an order that everything gets assembled into a
transformation matrix.

Currently we have:

apply motion (= motion translation, motion rotation)
apply translate
apply rotate
apply scale
apply transform

The translate, rotate, scale ordering is important so that those three
properties appear to operate independently of each other. We could move the
motion rotation to be at the same place as rotate, but it seems weird to
split the motion components like that.

>
> I.e.
>    apply motion
>    apply rotate
>    apply translate
>    apply transform
>
> You're saying that 'rotate' affects the coordinate system of 'translate'?
>

No, motion rotation does.

Cheers,
-Shane

>
> ~fantasai
>
>
```
Received on Wednesday, 18 May 2016 03:11:47 UTC

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