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I found a lot of similar questions about the Cell Fracture add-on, but all with different issues. As you will notice from the screenshots, (Blender version 2.83 LTS) between frame 125 and 126 you can see how Suzanne explodes just before the impact of the spiked ball, although she has set the Margin to 0.0001 as well as the shape has been set to Mesh and not Convex Hull. Below, following some tutorials, I also followed the advice to fix the bug of the chain that breaks, decreasing the speed and increasing the steps per frame and the solver iterations (unlike version 2.92 for example, which terms change to '' substeps per frame '').

Let me know and you need the file which in this case I will load it.

Thanks in advance.

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  • $\begingroup$ The answer is to place the original (non-CF'd) model at the same location. (use SH-S to do that if the cursor has been moved) Make the CF'd version invisible at frame 1 until the impact frame. Make the non-CF'd (added) model visible at frame 1 and invisible at impact frame also. This will also conceal the cracks and preserve texture until impact. Example here - 1drv.ms/u/s!AtkhCKZLZs_Pg2TaYxgtg5HPV-KU?e=1qKD5R $\endgroup$
    – Edgel3D
    Mar 21, 2021 at 5:11
  • $\begingroup$ Thanks, now I'll try and let you know. In the gif you linked, however, the black ball disappears on impact. @Edgel3D $\endgroup$
    – Albizz
    Mar 21, 2021 at 20:43
  • $\begingroup$ How do I set visibility on keyframes? @Edgel3D $\endgroup$
    – Albizz
    Mar 21, 2021 at 21:05
  • $\begingroup$ That clip was actually made to answer another similar query. The ball/sphere is just scenery for that particular demo and was told to disappear. It could just as easily be made to shatter and it's own debris mixed with the cube's. With cell fracture collisions I don't usually apply physics to the mobile object. An invisible plane (passive rigid body, curved or otherwise) is placed inside the cube and gives me good control over where the debris is to land and how it erupts. The CF is directed to remain passive until the desired collision frame. Cont... $\endgroup$
    – Edgel3D
    Mar 22, 2021 at 0:52
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    $\begingroup$ Yeah good, do that, try the dummy ball also. We're being told to move this to a chatroom so I'll do that now... God luck with it all $\endgroup$
    – Edgel3D
    Mar 24, 2021 at 21:14

1 Answer 1

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The Cell Fracture and physics process by default start at frame 1, and that has to be delayed. After you do the fracture, select all segments and press Ctrl + L to link them all. Choose Animation data.

Now what you keyframe on one will affect them all. Select one segment, set and keyframe it's physics to Animated at frame 1. Untick and keyframe the Dynamic box also.

Move the timeline to the collision frame (or there-abouts) and keyframe the boxes in reverse. Animated unticked and Dynamic ticked.

Addendum 1st April 2021

  • One thing further to the above. If the physics are still activating at frame 1, save the file and exit Blender. Reload it. This will clear the physics cache.

Apparently the procedure has been changed in vers 2.8+ and the new method is set out here - linking objects in blender 2.8

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  • $\begingroup$ I understood your example but if you illustrated it to me with screenshots it would be easier. Why '' Select one segment, set and keyframe it's physics to 'Animated' at frame 1 ''? If set as you say in frame 1, it all explodes at the beginning of the animation. I would say this method doesn't work. $\endgroup$
    – Albizz
    Mar 30, 2021 at 22:38
  • $\begingroup$ It doesn't work on all segments but only on one. Do I have to set them one by one? I believe there is another method. $\endgroup$
    – Albizz
    Mar 30, 2021 at 22:43
  • $\begingroup$ I tried the linking feature before I posted that comment up in the chatroom. I've just done a search for that and apparently the procedure is different in vers 2.8+, so I've included a search link below. For more, just search for "Linking". There are two distinct types. One where you can link assets from another object in a different Blend file, and the 2nd where you do as I suggested, link several existing objects together. If you can't manage what you'll read in the link below, - (see next comment) $\endgroup$
    – Edgel3D
    Mar 31, 2021 at 4:29
  • $\begingroup$ Cont... There is a workaround that should bypass the new system and force Blender to link the segments regardless but see how you go with this first... see the last answer given there - blender.stackexchange.com/questions/141324/… $\endgroup$
    – Edgel3D
    Mar 31, 2021 at 4:30
  • $\begingroup$ Perfect, after several tests and several connections, I was able to set keyframes for all CF debris. since we are on the subject, observing the animation, the ball in the moment of impact, has a small recoil but I think it is due to the weight I have attributed to my objects. Also to make a change of this kind must necessarily run clean keyframes, from scratch. Because otherwise everything blows up like a bomb. lol $\endgroup$
    – Albizz
    Mar 31, 2021 at 23:17

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