How to Do Breaking Effect

I need to create an effect in Blender 2.5 of a cube like object breaking through a roof with debris flying everywhere. I do not need to animate as it will be for an illustration.

Is there a way to do this so I can have it stop in motion and then turn the parts into actual geometry like the image?


If it is for a still I would be very much inclined to just do it manually. I think it would be much faster in the long run than dealing with physics.

I would just create the roof with the jagged splintered hole and the box, then create pieces designed to look like debris, place those in the air where you want them, and you could fake motion blur with a blur effect where desired in the compositor or in a photo app.

Thanks Richard. Yes in the end I may just build it manually but I’d like to explore other methods too just to see if there might be an effective option that might work. About the roof. You mentioned you would just model a roof with a jagged splintered hole. What do you think the best way to approach this would be? Would you just model the roof as polys with no depth, then cut out areas where the timbers were missing or would you give the roof some depth? I want to build this as a low poly model but I want it too look believable.

If someone has an idea how I could do this with some sort of physics, then i would like to explore this method too! :slight_smile:


Personally, I would give the roof a little depth, but it really depends on what your shot is going to show. If you won’t see it in the shot, forget it.

Also you might try using a particle system emitting objects from a group of generic debris objects for the flying stuff. You could also use this to spawn debris around the roof or the ground around the house with a second particle system. Then you could bake the dynamics and use some artistic license to remove any objects that you don’t like, or are blocking parts of the shot you want to see.

Thanks 0knowledge, not sure how you think I should add depth. Can you explain. Also about the particle system spawning objects. How do you get particles to use objects? Care to post a screenshot or .blend?

Here is an image of the roof in progress. i am not too happy though and may look at alternative methods to do this.
I was also thinking of using an “alpha” to create the hole in the roof, but then I couldn’t have any thickness to the roof because the hole wouldn’t show through the roof.

Any suggestions as to how I can model this so it looks convincing would be appreciated.


For adding depth. First I would separate all the plank like pieces you have sticking up from the roof (if they are part of the roof mesh), then you could either just extrude the entire roof down a little or just extrude the edges around the hole if you don’t want thickness everywhere.

As far the particles. In the render panel of the particles settings there are object and a group buttons. If you select the object button you can put the name of an object in and it will put an instance of it for each particle. If you use a group it will take random objects form the group you put in the field and replace the particles with them. However, if you’re not familiar with the particles system you may want to just do it manually, otherwise you’re going to have a lot of learning to do, as there are a lot of settings to play with.

Another approach would be to make the roof out of separate slabs. Then run each one of those through the fracture me script. This will make the broken pieces for you and prepare it for dynamics, if you go that route.