[Bf-committers] Voronoi Explode and Rigidbody Modifier Branch

Martin Felke martin.felke at t-online.de
Sun Sep 15 19:37:48 CEST 2013


i am working at a voronoi fracturing system in blender which supports
viewport bullet physics.
It consists of an extended explode modifier which allows fast voronoi
fracture using the library voro++ and additionally boolean intersections
and a rigidbody modifier. 
With the explode modifier a mesh is decomposed to a couple of voronoi
cells. Those are parts of the original mesh, each cell contains a set of
connected vertices. The cells are not connected to each other, thus
allowing to be moved independently. This can be utilized for particle
animation or even a rigidbody physics simulation. 
The second part is a rigidbody modifier which allows multiple
rigidbodies per object. It takes the fractured mesh from the explode
modifier. It also can take any mesh, for example result  from an array
modifier and turns each mesh island into an individual rigidbody which
is put in the rigidbody world and can interact with other rigidbodies
with or without modifier, it acts like a regular rigidbody. Settings are
made analog to the regular rigidbodies, and apply to each shard, except
for the mass, which is calculated from the volume fraction of the shard
in relation to the total object volume.
Benefits are a better handling of fractured objects -> many rigidbodies
in one object means less object overhead and also a slightly higher
simulation speed.
Recently i could improve performance of the mesh island and constraint
construction and of cache playback speed, its speed almost doubled and
is now only slightly less than with single objects, because of the need
to copy the modifiers derived mesh before returning it (blender frees it
outside the modifiers)
I also added a convert to object operator recently to create a
"compatible" version of the fractured object consisting of individual
objects, including constraints if they were enabled in the modifier.

You can find some documentation and a link to the sources on my


There is also a collection of builds available, currently in my dropbox.
The link is at the outdated graphicall build entry for Win64, but the
dropbox directory contains 5 builds: win64, win32, win32_vc9 (for win
xp, compiled with VS 2008 Express), linux64 and osx64.


At the bottom of my graphicall build site you can find 2 demo videos
from Kai Kostack showing a result which was achieved with my modifiers.

Furthermore there is a Blenderartists support thread, dealing both with
my addon and my modifiers:


I am working since February 2012 at my object_destruction addon, which
is bundled with the builds, and since February 2013 I work at the
rigidbody fracture system.

I just wanted to make some advertisement for my project this way and
hope that it gets more attention among users and developers.
Unfortunately i will have to wait until 2.7/2.8 or later until trunk
review can begin, because at the moment the modifier implementation does
not fit into a well designed new physics and fracture system of blender,
which is still to be defined. This is a huge task and involves many
people, thats why it might take a while. 



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