Crushing Metal Using Soft Bodies In Blender

I just recently watched this tutorial by GreyscaleGorilla on how to smash a van by using  “Plastic Deformation” in Cinema 4D. I thought it was a really cool and interesting way to do that, but since I don’t have Cinema 4D, I decided to try to see if I could achieve the same effect with Blender. It was actually pretty simple, a lot of the things were pretty similar. And since it’s so easy and so cool, I thought I’d share it and make a small tutorial. Also, for this tutorial, I kind of assume that you know the basics of Blender.

This is the result we want to get at the end of this tutorial:

Alright, let’s get started…

  1. Find an object you want to crush.

– In order for you to crush and destroy something, you actually need to have something to destroy. For this tutorial, I am using a trashcan model made by “ClayOgre”, which can be downloaded here from Blendswap.com.

Trash Can Model by “ClayOgre” from BlendSwap

– You can use whatever model you want, whether it be a car or a soda can or even a fork, as long it’s made out of something like metal in real life, it should be good. And don’t worry if it’s its a bit hi-poly, I’ll go over that next.

  1. Simplify the model.

– Usually, some parts of the model won’t be needed for this simulation. For example, the handles and the little screws that were on top of the trashcan I’m using should probably be deleted. Feel free to leave them if you want, but if its something like glass windshields for a car, it would be best if you removed, because glass doesn’t bend like metal, it shatters.

– Also, you going to want to join all the components of the model. For the trashcan, I joined the cover and the main part together by selecting both of them and pressing Ctrl+J. I also joined the bottom part because it was separate for some reason.

Before and after you simplify your model

  1. Make a “Cage Mesh” for the model.

– If your model is fairly hi-poly, or even mid-poly, then you’re going to want to make a cage mesh. A cage mesh is just a really low-poly version of the actual model. The simulations will all be applied to this mesh and then later we will make it so that it affects your actual model. Applying all the dynamics and simulations to a low-poly model makes thing run faster and smoother.

– For your cage mesh, you only really need the basic shape of the actual model. For the trashcan, I just made a very simple cylinder and adjusted the shape a little bit to match the trashcan more. Now, make sure that your cage mesh is bigger than the model that you want to crush. But not too big, get it as close to the mesh as possible without letting the hi-poly version stick out of the low-poly version.

Before and after you create a cage mesh

– A good way to make sure that your cage mesh isn’t intersecting with your hi-poly model is by using the “Shrinkwrap” modifier. Go to the “Object Modifiers Tab” then add “Shrinkwrap”. Make the “Target” your hi-poly model. Now make the offset to something like “0.075 – 0.100”. If your cage mesh is looking a little bit deformed, click the checkbox that says “Keep Above Surface”. This will keep the shape as it is, but still allow you to scale it up and down. Don’t forget to press “Apply” when you’re done with it.

“Shrinkwrap” modifier settings

  1. Setup the Soft Body Dynamics for the “Cage Mesh”.

– You can now hide your hi-poly model, H key, because you won’t need it right now. With your cage mesh selected, go to the “Physics Tab”. Then click on the “Soft Body” button to add soft body dynamics. Now go to the “Soft Body Goal” dropdown menu and uncheck the box that is automatically checked.

“Soft Body” under the “Physics” tab

– Now go to the “Soft Body Edges” dropdown menu and change the “Plastic” value to “100”. This makes it so that when the mesh gets deformed, it stays deformed. This is what makes the metal dent.

– We have the denting part, but it still falls like cloth. So change the “Bending” value to the max of “10.000”. This will make it more stiff. Also change the  “Push” value to “0.800”. This also makes it a bit more stiff.

“Soft Body Edges” panel settings

– Now, move the object up, press Shift+A to add a Plane, then add a “Collision” modifier to that plane, then scale it up a bit. Now press Alt+A to play the animation. Your object should fall and land onto the ground, deforming it and denting it.

Scene with added cubes and a plane

  1. Add the “Mesh Deform” modifier.

– Now that we have the physics all set up, we want to make it affect our hi-poly object. Unhide it by pressing Alt+H and move it to match up with the cage mesh’s new position. To make it get affected by the cage mesh, you need to add a “Mesh Deform” modifier.

– A “Mesh Deform” modifier allows a certain mesh to control how an object deforms. For the “Object”, choose your cage mesh. The “Precision” amount is how accurate the binding is. The higher it is, the more accurate, but it also takes longer to calculate. I usually just put it at “4”. Now just press “Bind”.

“Mesh Deform” modifier settings

  1. Tweak it.

– Press Alt+A to watch your animation. You can add some cubes and make them have collisions, and put them in the way of your object to make the fall more interesting.

– Watch your animation, tweak the settings in order to get it how you want it.

  1. Bake it.

– When you’re finally done tweaking the settings, you can start “Baking” it. Baking saves out the simulation and you don’t have to calculate everything in real-time, which can sometimes slow down your computer. Before you bake it, there is a few things you should do.

– In the “Soft Body Cache” dropdown menu, make sure that your “Start and End Frames” are set to what you want it to be. Change the “Cache Steps” to from “10” to “1”. This changes the amount of frames between each cached frame. If it’s at 10, then it will only cache every 10 frames, but at 1 it will cache every frame.

“Soft Body Cache” panel settings.

– Also, in the “Soft Body Solver” menu, you can change the “Error Limit” to “.050” to make it more accurate. You can also change the “Min Step” to “50-75”.

“Soft Body Solver” panel settings.

– Now you can press “Bake” and watch your animation. When you render your image, make sure that the cage mesh doesn’t get rendered or else it will block your hi-poly object.

I hope this tutorial helps someone out and was easy to understand. I will try to make more written tutorials whenever I find something interesting or cool. If you have any questions, just let me know in the comments and I’ll try to help.

If you want, you can also download the finished .blend file that I provided. It follows the tutorial exactly, but some people learn better by seeing and playing with the result themselves.

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