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Hello i have such an object:

enter image description here

I want to achieve such a result so that it turns out like this:

enter image description here

BUT there should be no cracks.

I know that you can use a special blender assembly, but unfortunately I cannot use it.

So I thought, why not take a shard and use a boolean modifier to subtract this shard from the main object.

But I can't do it...

Artifacts appear in the form:

enter image description here

Editional:

enter image description here

enter image description here

with more scaling

enter image description here enter image description here

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    $\begingroup$ Are you using the "Fast" or the "exact" setting on the boolean modifier? Exact should be better here due to the overlapping of the outer faces. If that does not work try this: Since the outside surface is the same (or very close) to the surface of the original sphere it might otherwise help to scale the fractured part slightly (e.g. something like 1.001) so that it is clear which surface is the outer surface for the boolean operation. $\endgroup$ Jun 23, 2021 at 10:36
  • $\begingroup$ Hello, i use Exact setting on the boolean modifier. Your solution to scaling the broken piece really works for a simple object, but it does not work quite correctly with my more complex object, see what else you can do, I have attached more photos in the post. $\endgroup$
    – Semyon
    Jun 23, 2021 at 11:25
  • $\begingroup$ Just scale wouldnt work since some parts of complex shape moves inside due scale shift ... scale works only for objects like sphere. You can dupli shard and add solidify modifier and Boolean to merge with original shard to get working shard object (if it is not clear I can add some screens) ... but it seems to me overcomplicated for such thing ... why dont use cracked cube to boolean from glass object? The best if you can show what is your desired result you need to achieve. There is also awesome Fracture Modifier in special build. $\endgroup$
    – vklidu
    Jun 23, 2021 at 14:09
  • $\begingroup$ @vklidu, My main goal is to generate a lot of "bad" data for the neural network. I added in the post specifically what I would like to get, can you please advise how to do this. The problem is that this object is glass, and if you just break it with a cell fracture, then cracks will be visible throughout the object, and I just need a single straight/curved cleavage. Please help me how to solve this problem. $\endgroup$
    – Semyon
    Jun 23, 2021 at 14:46
  • $\begingroup$ Please share your file blend-exchange.com I still didnt get it why to use crack of original mesh, why don't use a plane or cube or cylinder to Boolean that part away. $\endgroup$
    – vklidu
    Jun 23, 2021 at 15:07

2 Answers 2

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To automate process for variations try to search for it or ask a new question (if you didnt find it) ... I can't help you with a script, but for such think a few modifiers can do the same job. Here just a tips for the workflow.


Create one "crack" shaped by a Displacement modifier with Noise texture. To get object variations, set Coordinates > Global. Now the object is shaped based on its location.

enter image description here

Add Boolean modifier to your object.

enter image description here

By relocation your object you can generate variations.

enter image description here

To get hundreds in a minute you can duplicate it once and Repeat last step Shift+R or use Array modifier.

enter image description here

When it looks OK for you, Apply > Visuals Geometry to Mesh Ctrl+A for all objects at once.

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Just for illustration ... Why not something simpler?
Here from Mesh profile > Screw > Subdivide > Boolean ...

enter image description here

Plane ... enter image description here

Cylinder ... enter image description here

... or any other object like a shard of Cube object split by Cell Fracture modifier.

enter image description here

Tip: For more efficient work with fractured object might be useful Fracture modifier (included in special Blender build). In this case for glass reason - modifier releases cracks after they are recognised by simulation as part that should be separated. So no cracks in anim before.

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  • $\begingroup$ I need to automate this process with a python script. That is, I need thousands of different variants of chips, so it seemed to me the most logical algorithm: 1. We split the object. 2. Take a random shard. 3. Subtract this shard from the main object. Yes, I agree, with the help of a grid or other various objects, my main object is cropped nicely and without any problems and is quite beautiful. But I just need automated generation. $\endgroup$
    – Semyon
    Jun 23, 2021 at 16:04
  • $\begingroup$ It is really hard to understand your goal, your reference doesn't seem to have anything similar what I can call a chip (or neural network) or it is hard for me to understand how "crack" should looks like from your description "my object is cropped nicely without problems and is beautiful". Anyway I can't help with a script so just a tip with modifiers that can generate "hundreds" versions in a minute. See another answer. $\endgroup$
    – vklidu
    Jun 23, 2021 at 21:20

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