Create irregularly shaped gaps in cube I need to create a cross section of a surface (which takes the form of a cube), and therefore there are certain areas which need to be "empty". A visual description of what it would look like is below:.

Moreover, it might be necessary to include that there is a particle system that is emitted from the surface, and these particles should not be emitted from "empty area".

Things I have tried:


The cell fracture add-on... to not much success. Not sure if I am using it incorrectly.
Simply deselecting 50-80% of the faces (I subdivided the cube already) and then deleting them.


None of these methods create an optimal output. Any help would be appreciated!

EDIT: Here is what I have so far:


The yellow portion is to be modeled like the green cross-section provided before. As you can see, the small black-white bits on top of the yellow is a particle system that is frozen to 1 frame. So, tying everything together, I'm trying to model yellow area to look like the green image shown earlier, however the particle system must only emit from the non-empty areas.
OK, I'm still not sure what you need exactly, how it differs from what you already got or why yours is not satisfactory, but here is what I came up with.



Just add a simple cube to your scene, and a small Metaball. Adjust the Meta Ball size as desired, but make sure you apply the scale and adjust precision correspondingly afterwards.

Now add a particle system set to Volume to the Cube object, and under Render as particle object add to it the Metaball. Adjust the number of particles as necessary. A high number is expected, and so is the corresponding slowness and unresponsiveness, just give it a little.

Make the particle system emitter invisible (make the cube draw as Wire only so you can see what you are doing too), and tick Unborn and Died, also turn off physics.

Once happy with the settings select the original metaball (not the cube or particle system) and convert it to a mesh. Manually erase the stray original metaball, then you can add a Boolean modifier to it, and intersect with the original cube mesh.



To keep distinct materials at the intersection faces just add a second material slot to the object with the Boolean modifier before applying it.