# How can I create realistic gravity in HF4P?

I'm doing something simple I think.  I want a logo to "drop", as in fall to the bottom of the screen and "bounce" a bit, that sort of thing.  But I couldn't find a way to accomplish that with an effect, and my manual attempt is horrible Claymation. :-(

If Shirley was here....  Shirley there must be a way to accomplish this in HitFilm?

:-)

Chris

• edited September 2016

Fast - Keyframe the fall down and colorize it to match the scene. Then duplicate the falling object, colorize it black, lower the opacity, angle it slightly to form the shadow. Add motion blur.

Accurate - Rig your area in 3D space with planes, throw in your object, light and shadow the object to match the scene, keyframe the fall, this will be more time consuming but will look better. Plus its a good technique to learn how to do. Add motion blur.

Heres a tutorial I did a while ago for the Fast method, hope that helps.

https://youtu.be/_HnkOTzOYPg

• edited September 2016

Keyframe positions (only needs about 6 ) and play with the types, such as Linear, Smooth, Bezier etc.

Tops of your bounces should be Smooth, the bottoms: Linear and the time for each bounce should be the same from start to finish, but each bounce shorter in time and lower in  height than the one before.

It's probably easiest to assume it's at terminal velocity when it enters the frame, to avoid having to have it still accelerating, Then up, down, up, land.

Something like this, although on the spot - unless you also want to to move sideways.
http://i854.photobucket.com/albums/ab106/pickaname2/bounce.jpg

You might want one more depending on how 'rubbery' it is, but the heights want to drop off in size very quickly, like 1080 (screen height), 150, 30, 0 and the gaps between each bounce get smaller. And the whole thing should take less than a second,

You could potentially add some rotation so each end bounces slightly differently before it settled if you want to get fancy.

• Moderator

Realistic approach:

Things needed - Camera on a tripod or other stable surface, a ladder and a ball.

Set up scene, start recording, climb ladder, drop ball.

Import clip, track ball and apply tracking to point layer and parent the layer you want to bounce to the point.

Advanced work - Study the key frames of the point and try to re-create the movement with a few manual keyframes like @Palacono suggested. Also check out this thread for more suggestions and some of the math

http://hitfilm.com/forum/discussion/41249/jumping-a-car-effect#latest

• Staff

I'd just use the physics built into the particle engine.

• Use it as a texture on  a particle effect
• Set up the particles so a single particle is spawned
• Add a floor plane and a gravity force, so the particle (your logo) is pulled downward by gravity until it hits the floor plane
• Adjust the bounce, mass and friction to get the physics working the way you want them.

• By the way I did use the single particle emitted approach.  Worked out pretty good even with a newbie on the job, but I was playing a bit and not delivering to someone else's vision so I adjusted to suit my skill level. :-)

I had it emit downward onto a floor plane, and then as the credits rolled a slightly angled "pusher" plane tracked the first line with 0 friction,  that pushed the logo particle over until it dropped and slid over the the bottom left corner to a normal logo spot.

And then it disappeared into a space/time warp flare effect, until the vfx credits came up and zapped it back into visibility.  Of course. heh.

Thanks for the help with my first fun. :-)