Animated chain either breaks or crashes blender

I’m quite new to Blender and wanted to try some simple animations. So I created a chain out of 30 links, activated rigid body to all of them (like in a YouTube tutorial), fixed the left most link and hit the Animation button.
Since my computer probably isn’t the best for 3D animation it took quite some time between each step of the animation, but at least I could watch the right side of the chain to fall down and dangling from the fixed left most link. But somewhere in the middle of the animation, my chain broke up as if one of the links couldn’t bear the weight of the other links.
I googled a little bit and someone said, that the physics simulation in Blender behaves oddly when measurements and/or weights do not fit. So I checked my chain and realized that each link of my chain had a radius of 1 meter.

So I deleted my giant chain, and created a new one, with each link of the chain having a radius of 1 millimeter (I try to create a chain necklace). And with such small links I turned down the weight of each link in the rigid body settings to 1 gramm (seems to be the minimum).
My new chain has only 10 links to speed up the animation.

But now, when I hit the Animation button, nothing happens, and when I click into Blender agian, it turns white, and nothing happens anymore. It seems to be crashed.
I tried to turn up the weight of each link in steps to 100g, but the Animation still crashes Blender.

Of course the shape of each link inside the rigid body settings is set to Mesh.
Oh, and my Blender version is v2.81.16

So, what am I doing wrong? The attached blend file is the one crashing when trying to animate.

chain.blend (2.5 MB)

First off, I’m not really a sim guy and I didn’t really dive into how to do physically correct simulations in Blender, I was just curious why the scene was crashing.

The chain may be way too small, the rigid body world defaults have a hard time dealing with it. Either you increase the size by a lot (*1000) or you increase the substeps in the rigid body world.

I’ve done both (increased steps per second to 400 and solver iterations to 50 to play it safe) as a test (default settings for the rigid body so the sim looks a bit jumpy out of the box) -

I’d probably reduce the polycount for simulations like these (and constraint or parent my render geo), there’s a lot of unnecessary information Blender needs to calculate.

Thank you, but where would I change these settings? I don’t find any settings called “steps per second” or “solver iterations” in the rigid body settings? And if I increase the chain by factor 1000 then I’m back to a chain with 2-meter links, which broke apart in the middle of the animation?

They’re in your scene settings.

Not enough simulation steps per second might have been the reason for the animation breaking rather than the size of your links.

Not sure how relevant real world size is, I tend to have more luck with bigger objects and rather adjust their weight/speed to get closer to my reference.

Again, I’m not an fx guy, so this advice might send you down the wrong path. The sim didn’t seem to break or crash though.

1 Like

You might want to try with the Blender 2.91 alpha as it has a new feature for this specific use cas:

@dan2: Thank you. I’ll play around with these settings.
@Lumpengnom: Thank you, but I’ll wait for version 2.91 to be released.