vortex dop orientation

[Magnus Pettersson]

Hello i got a little problem. I got a object animated at object level (animated with a path object) and want to attach a vortex force that follows along, but i cant seem to get the orientation of the force to follow along the animation, how do i get it to orient with the animated object? Maybe i have to do some fancy tricks with the direction vortex parameter?

It works fine if i animate and rotate around the vortex curve sop object with a transform SOP but not when animation comes from object level (which is where most of my animation will come from).

I attached a simple setup scene that shows the problem where the vortex force is staying aligned with the worlds Z axis.

thanks for the help

/Magnus

vortex_orientation.hip

[Emanuele Berti]

Hi Magnus,

There is an easy way to solve your problem.

I just used a new geometry obj with a obj merge that points to your OUT_vortex sop,

then in the sopgeometry DOP I pointed to the new geometry obj instead of the OUT_vortex null.

I hope this solves your problem.

Cheers,

Emanuele

vortex_orient_fix.hipnc

[Magnus Pettersson]

I just used a new geometry obj with a obj merge that points to your OUT_vortex sop,

then in the sopgeometry DOP I pointed to the new geometry obj instead of the OUT_vortex null.

I hope this solves your problem.

Cheers,

Emanuele

Simple and cleaver solution! Thanks Emanuele, that solves it

Do you know why this is like it is? Is it something about how the local/object/world transformations and how the vortex field is applying its direction or something?

[Emanuele Berti]

Hi Magnus,

I'm not an expert so, I can only guess.

I tried to set the display flag on OUT_vortex sop, in DOP take a step back, pointing at it from the sopgeo1 but it seems that it doesn't take the right orientation, so the reason is not where the display flag is.

I also tried to animate by keyframes the tube_emitter_and_vortex obj to avoid the path object, but the problem is still there, so the reason is not how the path object transfer the orientation to the object which is apply to.

I believe that the vortex DOP take the orientation from the points of the line and if you take a look at the details view there's a difference in position and orientation between the points inside the tube_emitter_and_vortex and the other inside the extract_vortexLine.

In the first case there are two different level of transformation so the points looks static at the SOP level, in the second one they are merged into one so the transformations look transfered at the SOP level and the vortex DOP can orient itself in the right way.

Cheers,

Emanuele

[Magnus Pettersson]

Yeah i also tried in the beginning if it was animating by a path that was the trouble so i tried keyframing but that didnt work. Thanks for your insight, it sounds like its how it works because like you said, the points look static in the SOP since they are not moved in local space since its the "parent" that is animated and when object merging into a new geo node with bringing in its transform the points are actually moving in sop space. At least it works by bringing it inside a new geo node so i´m happy

/Magnus