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Is there a way to make custom fractures in cell fracture, like specific shapes to fracture with? I dont have much experience with cell fracture.

What I am looking todo is to take a sphere, and have it crack into a ying yang symbol. So the only fracture I would be looking todo, I the 1 crack that splits the sphere into each half. That way I can seperarate the 2 pieces

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    $\begingroup$ yes you can do it with the grease pencil, as explained by CGCookie, part 1: youtube.com/watch?v=DEo_9AopfoQ ... part 2 : youtube.com/watch?v=QY7iJmqsJf8 $\endgroup$ – moonboots Aug 27 '19 at 7:50
  • $\begingroup$ This was really cool and usefull, but not what I'm looking for exactly. I will update my question. $\endgroup$ – Nick Sieben Aug 28 '19 at 14:10
  • $\begingroup$ so you could simply create your object, then print an edge on its middle with the Knife Tool Project, then separate the 2 parts it has created... do you see what I mean or do you need a complete explanation? $\endgroup$ – moonboots Aug 28 '19 at 14:14
  • $\begingroup$ I think I understand. I will play with it and get back to you $\endgroup$ – Nick Sieben Aug 28 '19 at 14:15
  • $\begingroup$ Ok so your talking about doing it without the cell fracture.I understand that. You just select what you want to separate and press P correct? is there a way to fill the now unconnected vertices on the inside so there is quads not an ngon? $\endgroup$ – Nick Sieben Aug 29 '19 at 0:25
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You could do it the way below. I've used Susan's head for demonstration. Create two objects, the original one and the broken one. To break the object you'll use the Knife Project Tool. To animate you'll play with the visibility so that at frame X the broken pieces will replace the full head. You could even don't use the unbroken head but with my method you don't have to care about the joints between the broken parts if it ever causes problem (for example if your object uses a Subdivision Surface modifier you may see the fractures between the parts). As you suggest, boolean may also be a nice way to create the different parts.

  • Create your object. Duplicate, keep the duplication at the exact same place, and hide it for the moment.
  • Create a second object to draw the fracture lines.
  • Use the Knife Project Tool to cut your object with the help of this second object. Enable the Cut Through option in the Last Operation box.
  • Select the fracture edges, press V to rip.
  • Separate your head in 3 separate objects: Select each part with L then separate with P. Put them in the same collection.

enter image description here

  • Open your Dopesheet.
  • At frame 0, for each of your pieces, give a Rigid Body (Active type). Activate the Animated option and create a keyframe on it so that for the moment the physics won’t affect these pieces.
  • In the Outliner disable the viewport and render visibility of each of the pieces. Create keyframes.
  • On the contrary, enable the viewport and render visibility of the full head, create keyframes.
  • Open your Timeline. move the player from frame 0 to frame X.
  • Now switch off the visibility of the full head and create a keyframe, switch on the visibility of the fractured pieces and create keyframes, disable their Animated option and create keyframes.
  • Play the animation, at frame X the head should break and fall apart.

enter image description here

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  • $\begingroup$ Thanks, I was over complicating things. This keeps it simple. $\endgroup$ – Nick Sieben Aug 29 '19 at 13:01
  • $\begingroup$ you could even don't use the unbroken head, but with this method you don't have to care about the joints between the broken parts if it ever causes problem $\endgroup$ – moonboots Aug 29 '19 at 13:09
  • $\begingroup$ Yes, that what I was thinking too. I think im gonna use a boolean type of reveal for the cracks, and play with drivers( for the reveal to create a cracking effect. Thanks again for the help $\endgroup$ – Nick Sieben Aug 29 '19 at 13:36
  • $\begingroup$ oh yes of course, booleans are another good way to do it (needs a test though) $\endgroup$ – moonboots Aug 29 '19 at 13:39

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