Point Info (DP-kit) and rotation problem.

[serge]

Point Info doesn't seem to output point normal rotation correctly.

Example:
I've attached cloned cubes to a box object (with Node Item Motion and Point Info). The cubes are placed and rotated correctly with the point normal. But when I deform the box (I slightly curved the top) the rotation of the cubes becomes incorrect.

(Same problem with nodal displacement instead of Node Item Motion.)

[dpont]

Yes heading seems exagerated in second sample,
the simple function used to calculate angles
has shown its limits here.

Denis.

[serge]

heading seems exagerated...
It's the 'bank' in this case (the cubes are modeled with the green part in Z+ direction).

Denis, is this something that can be fixed with nodes, or do you think you can improve this in a future release? I have some great ideas in mind if this would work :o.
'Part Move' also works with Point Info, so there's no more need to clone objects in Layout. This opens tons of possibilities as all Modeler clones are one object and motion can be saved in one MDD.

[dpont]

Like 'Align to Path' it calculates heading an pitch
angle but based on forward (Z+) direction,
so you get useless fake bank (heading) on
Y+ normals, but should be correct with normals
Z+ oriented,

70521

Denis.

[serge]

...so you get useless fake bank (heading) on Y+ normals...
Is this a Lightwave limitation or Point Info? Do you think there might be a solution?

edit: I guess the "fake" bank explains why multiplying the bank output from Point Info didn't change anything (because this output is zero).

[dpont]

I said 'fake bank', because in Point Info node is always zero.

Not Lightwave, not Point Info, rather trigonometry,
until Z+ is the reference for the function,
it could work with any other reference, even negative,
but this node has been designed for general 3D usage,
any other specific change in its reference axis,
could failed under other contex, so this limitation
can't be simply fixed.

Denis.

[serge]

I see, that's a shame. I got very excited today to find Part-Move working with Point-Info. I couldn't stop thinking of the possibilities this could have for animation.

Thanks for the reply, Denis! (I'm still going to hope you might find a solution :))

[dpont]

I can get something better, exporting directly
a Point Info world normal (with a Nearest Point index input)
to the 'Direction' input in Part Move node, except that Point Info failed
to export correct point normal at some place.

Node tree,
70725

Animation,
70724

Denis.

[serge]

Thanks for the update Denis! I'm going to test.

[serge]

Yes, "direction" input seems better, but there are still rotation problems.


Image 1:
Same setup as your example. I used a morph to bend the plane.


Image 2:
I compared the positioning of cloned objects/parts. (The cube is modelled with the green in Z+ and red in Z- direction.)
First picture is the cube cloned in Layout, and positioned on the box with Node Item Motion. The result seems correct.
Second picture is the cube cloned in Modeler, and positioned with Part Move, rotation input.
Third picture is same as second picture, but direction input.

So, rotation by Part Move does not seem to be correct yet. (I also tried flipping a face to get a "dominant" normal, as you explained on your website, but that didn't seem to make any difference.)

...