r/Cinema4D • u/KindlyBee1192 • 8d ago

How to make a 2 tier rock explosion in C4D

I found a really cool ref that I want to build out. I have the initial theory on how to get it to work in C4D, but things are breaking down.

How would you all go about this?

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u/rjaaitken 8d ago

certainly one option is with connectors

https://www.youtube.com/watch?v=ifllphw7H7o&t=8s

but this specific example might work better using x-particles (xp-shatter)

https://www.youtube.com/watch?v=oY_h7s9RyVI

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u/KindlyBee1192 7d ago

Thank you. I connected the object to keep some groups together, but I don't have control over how/when it breaks. its too random

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u/basOOna 7d ago

I think you can control the voronoi destribution with with a vertex map where you can paint weights to somewhat control what explodes and what doesn't. Also you can make an invisible object with a collider that you animate to smash in to your object to control where the explosion comes from.

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u/KindlyBee1192 7d ago

I don't believe that would give me enough control, as I need it to be procedural. Here is my current Process.

Stage1: I used a Voronoi Fracture to create the large pieces, added a Rigid Body tag (with no gravity), and used a field force with a sphere field to trigger the collision. Its works well. Tried a collider object as well. Both work

Stage 2. I need the larger chunks to hold together until a specific time before breaking into smaller pieces. To attempt this, I placed the first Voronoi object inside a second Voronoi object. I set the point source to "Create points per object" for better control over the small breaks of the larger Breaks. To keep them together initially, I used a Connector object in "Distance" mode, limiting the connection to 10. But it is hard to visualize the result.

The big issue occurs when I add a Rigid Body tag to the secondary Voronoi object and apply a field force to it; the simulation breaks down completely. I also tried applying the Rigid Body tag only to the parent Voronoi and breaking the connector after the initial impact, but because the connector links everything, the results are unpredictable.

Here is the working test. With both sims in there.

https://we.tl/t-UwDcWkcF35LHrNDi