Particle Sim: Moving detractor force mask camera-tracked

aknittel Website User Posts: 110

Has anyone discovered how to use a mask layer for a force and tracked it to a camera move.

I have a VFX that are particle system bees, but I want to keep the bees away from the tracked subjects face. There doesn't seem to be a way to specify a mask in another tracked (parented) layer to do this. Masks for forces seem to b e localized to the particle system and force and have to be keyframed manually to follow.

I don't think a deflector will work in this case which it seems you can specify a layer mask.


  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 19,791 Ambassador
    edited May 2018

    Deflectors can, of course, be assigned to layers, which means they can be aligned with tracked (or other) points.

    Unfortunately, forces cannot be parented to a point (That's been a particular wishlist item of mine for some time).

    Forces do need to exist in three dimensions so I doubt we'll ever get "Force to Layer." Hopefully a future revision will allow forces to be tracked to points. I'd also like for a particle system with "TARGET" trajectory to parent to a point, and maybe even "CONE" trajectory. Those additions would make a very powerful sim even more powerful!

    The only thing I can think of as a workaround is to track the subject's face, then copy/paste the actual position data from the tracker into the force's position properties. This will only give you X/Y coordinates, but, depending on how the shot is set up that could work. I'm assuming you've tracked with the point tracker? If not there's a way to track objects in mocha.You do a camera solve first, then go back and track the object once the camera is solved and export it's data. From there you'd again copy/paste the data directly into the position property of the force.

    Mocha Tutorial. It's Hitfilm 2 so the interface will be a little different, but I don't think any of the steps and workflow have changed.

    Hope this helps. :)

  • aknittel
    aknittel Website User Posts: 110

    I've tracked with point tracker. That's an excellent suggestion! I hadn't thought of copy/pasting the position data into the force's position properties. Makes perfect sense.

    Thanks, had to have someone think out of the box on this one!