new bullet integration how to animate with physics?

Just wondering if someone could tell me how for example to throw a boulder for instance off a cliff with the new physics integration. I’m thinking animate the boulder to give velocity and let the physics do the rest-- falling arc impacts etc.

Just the basic…

First, make sure rotation and scale is applied to everything. [CTRL A] in Object mode.

Open the the Tools shelf [T]. Find the Rigid Body Tools panel. Select your cliff and all the obstacles your boulder will encounter in its fall. Click “Add Passive”. Select your boulder, click “Add Active”. Keep it selected.

Go to frame 1. Set your boulder in position. In the Properties shelf, Physics tab, Rigid Body panel, check “Animated”. Hover the checkbox and press [I] to insert a keyframe. Go over your boulder in the viewport, press [I] to insert a Location keyframe.

Go to frame 10. Move your boulder over the edge of the cliff. In the Physics tab, uncheck “Animated”. Insert a keyframe. Go over your boulder, insert another Location keyframe.

Open the Graph Editor, select the 3 curves for the position of the boulder and convert them to Vector. [V]

Go back to frame 1, 3D View. [ALT A] to play.

Admire! :smiley:

The detail to make things a bit prettier: Use “Calculate mass” from the Tools shelf on all the objects participating in the physics simulation and select them an appropriate material.

The problematic detail: How far should you move the boulder to give the appropriate velocity? Your guess is as good as mine.

The hidden panels: A few rigid body related panels are hiding in the Scene tab. If the simulation is a bit jumpy, increase “Steps by Seconds” and “Solver Iterations”. (You can safely multiply the values by 2 without much time penalty… if there isn’t too many objects.) Next, the cache. Click “Free All Bakes” to make sure that the simulation is accurate after a change. If the button is disabled, increase or lower the “Solver Iterations” by 1. (That’s what I do. The influence is minimal and it re-enables the damn button every time.)

That should be enough for the first time. If you want to make the boulder explode on impact, come back for a second round. :wink:

Thanks so much! couldn’t figure out how to animate and use physics - I’m used to the older way of game engine baking which allowed you to add controllers for the velocity etc, but this is much simpler.