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:Cross section with gaps.

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: enter image description here

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.

  • 3
    $\begingroup$ Do you need actual geometry (as in this will be 3D printed) or can you live with a solution using textures? $\endgroup$
    – user1853
    Jul 17, 2017 at 20:57
  • $\begingroup$ It is not very clear what you already have and what you still need to achieve, could you please clarify? Do you have the green shape modeled already and wish to make a cross section of it? Do you have a particle system that produces that shape or is the particle system supposed to be emitted from the green mesh? $\endgroup$ Jul 18, 2017 at 0:09
  • $\begingroup$ @cegaton No I do not need actual geometry, a solution with textures is perfectly sufficient. $\endgroup$
    – student
    Jul 18, 2017 at 13:31
  • $\begingroup$ @DuarteFarrajotaRamos I have edited the question with the information you need! $\endgroup$
    – student
    Jul 18, 2017 at 13:33

1 Answer 1


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.

enter image description here

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.

enter image description here

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

enter image description here

  • $\begingroup$ Thanks, this is exactly what I needed for the background portion of the cube. I still need there to be some black/white striped particles on top of the portions of the cube that are whole. i.e, the parts that are not deformed inwards. Is there a way to do this from here? $\endgroup$
    – student
    Jul 19, 2017 at 15:17
  • $\begingroup$ Boolean modifier should keep materials by default, just add a second material slot to the object with the desired material for the intersections. Answer updated $\endgroup$ Jul 19, 2017 at 16:49
  • $\begingroup$ Is there a way to emit particles from the yellow portion of the cube? I tried adding a particle system on the Mball, but that did not work. $\endgroup$
    – student
    Jul 19, 2017 at 20:34
  • $\begingroup$ If you have any further questions please ask them separately in a new post, comments are not for extended discussions. Be sure to search before asking I'm sure you'll find many relevant answers $\endgroup$ Jul 19, 2017 at 23:02
  • 3
    $\begingroup$ You've made a chocolate crackle $\endgroup$
    – batFINGER
    Mar 21, 2018 at 18:56

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