Deflectors

sbradysbrady Website User Posts: 28
edited January 17 in Post-production techniques

I want to make rain fall on an umbrella. See link below. The only deflector I see is a cube. I need to put a sphere under the umbrella. How can I do this. 

rain on umbrella

Comments

  • kevin_nkevin_n Website User Posts: 1,921 Enthusiast
    edited January 17

    This can be tricky because you want it to look very real I assume?If you had a green screen you could create a miniature umbrella and then shower rain, however they may be too big. Rain is a tricky thing to get right, because there's going to be a splash and bounce effect that is hard to replicate by VFX means. You may also find some rain that's got what you need in free stock footage. The audio at the very least should be real rain just to sell it as much as possible, preferably with a few hits on an umbrella or similar surface.

  • triforcefxtriforcefx United StatesModerator, Website User Posts: 1,060 Moderator
    edited January 17

    @sbrady

     This is definitely a hard one to do with CGI. Hollywood would build an on set rig to “rain” on your actor. You could get a similar effect irl with a garden hose and a sprayer pointed in the air and the end point aimed at the umbrella. (I had way too much time as a kid...)

    Barring that, deflectors in HitFilm need some additions, but in the meantime, you should be able to set up multiple deflectors and build them in a somewhat spherical configuration. (I apologize for not being very specific- I’m still learning particles myself)

    Edit: I just remembered a large discussion of a similar issue. It’s a big thread, but looking around (on this page particularly) might help: https://fxhome.com/forum/discussion/43252/star-wars-9-vfx-zach-alans-productions-nov-17-2019/p6

  • NormanPCNNormanPCN Website User Posts: 3,945 Enthusiast

    Use planes as your deflectors. The planes do not need to be visible. You will need to use multiple plane deflectors to get the shape you are looking for.

  • Stargazer54Stargazer54 Moderator Moderator, Website User, Ambassador, HitFilm Beta Tester Posts: 2,715 Ambassador
    edited January 17

    @sbrady To add to what Norman said you will need to add plane layers (with Dimension set to 3D plane) and arrange them in a rough shape of the umbrella.  Then in the particle generator you add a Deflector, set it's shape to Layer then select one of the 3D plane layers..  You will need to repeat that step for each plane to be used as a Deflector.

    Also best to parent all your planes to a 3D parent point so they can easily be re-positioned together.

    Here is an older tutorial on particles and deflectors. You may not need the "mobile emitter" feature, but the principals of setting up planes as deflectors are the same.

     

  • sbradysbrady Website User Posts: 28

    this can be done very easily and quickly in Lightwave 3D, but Hitfilm is a different kind of app. They give you a cube to bounce particles off of, why not include a sphere. I guess I can add several cubes but it won't be the same end result.

  • kevin_nkevin_n Website User Posts: 1,921 Enthusiast
  • Stargazer54Stargazer54 Moderator Moderator, Website User, Ambassador, HitFilm Beta Tester Posts: 2,715 Ambassador

     @sbrady Absolutely.  It would be awesome if you could read in a simple shape from Lightwave or Blender and use that as the Deflector layer.  I have wanted that for years, but as @CNK said you need to post that to the Wishlist page at the top of the Forum so the devs will see it.   I'll certainly pile on and vote for it.

    BTW, don't forget that you can rename your Deflectors to more easily keep track of things.  (e.g. Cube-Left, Cube-Right, etc.)

  • NormanPCNNormanPCN Website User Posts: 3,945 Enthusiast
    edited January 22

    "why not include a sphere"

    One can why not yourself to the moon. That said, since this world is not terribly planar and angular, having a deflector with a curved shape like a spheroid, would/could be quite useful. Problem is the world is not terribly spheroid either. Still a spheroid can represent a hillside, depression, a grassy knoll and yes an umbrella. 

    I might why not myself to having text as a deflector. Titling fun.

  • WhiteCranePhotoWhiteCranePhoto Website User Posts: 896 Enthusiast
    edited January 17

    If you really want to do this in CG rather than the easier practical approach...

    In Blender you can configure an object to be a canvas with dynamic paint. You can configure the particles to be brushes with dynamic paint. I think you can also make the object a collider, though you might have to make a proxy.

    So, motion track your scene, or your umbrella if the camera is static (or both). Import that track into Blender. Or both tracks... use that motion data to define the motion of the objects, set up your particles using the new MantaFlow stuff, and Bob's your uncle. (Bob must have a lot of nieces and nephews by now.)

     Note: I realize I'm making it SOUND easier than it really is, but it is doable... though still a lot easier as a practical effect. :)

     

  • sbradysbrady Website User Posts: 28

    if I made a sphere in Blender, what format do you use when you export?  OBJ?  Will Hitfilm import an obj format, can I make that object a deflector? that would do what I need.

  • WhiteCranePhotoWhiteCranePhoto Website User Posts: 896 Enthusiast
    edited January 22

    I was suggesting doing the particle effects entirely in Blender, and then importing the result into HitFilm for compositing.

  • Stargazer54Stargazer54 Moderator Moderator, Website User, Ambassador, HitFilm Beta Tester Posts: 2,715 Ambassador
    edited January 22

    Afaik.  You cannot use a 3D object layer as a deflector.  You will have to use plane layers or the cube.

  • kevin_nkevin_n Website User Posts: 1,921 Enthusiast

    Lots of great suggestions here. I would lean towards planes too for speed but importing would be so cool. I think a lot of people would want that because there's only so many shapes in HitFilm currently. Looking forward to see the end result, if you choose to share it!

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