Issues > Annual Showcase Edition 2011 > Technique > CINEMA 4D:
Create Dynamic Soft Bodies

CINEMA 4D:
Create Dynamic Soft Bodies

Words by Scott Nolfi

Dynamics is an area of 3D animation that deals with the interaction of objects and forces. Instead of manually animating items and their attributes over time, referred to as key framing, dynamics allows us to set up the starting point and simulate the rest. While this limits our ability to get stylized motions, it can be much faster and very useful when trying to represent realistic phenomena. Dynamic simulations are used often in films, games and commercials. Smoke, fire, rain, explosions and many other effects utilize simulations to create stunning animations. With a little help, you can create your own dynamic “sims” in no time.

If you’re brand new to 3D, it is a good idea to familiarize yourself with the program and have a basic grasp of the workflow. This will help you to understand how all the different processes go together. The reference videos in the Cinema 4D help section are ideal for this. Take a quick look at those, and then jump back into the tutorial.

A startup scene has been provided with some basic items created for you. Our ShotCam is the camera from which we’ll do our final render, the bowl will catch all of our Jell-O pieces and the HDRI sphere will help to light our scene.

We will add some objects to our scene. I’m using a basic cube in this example, but feel free to add any of the primitive objects. Once in the scene, we’ll use the Move tool to position it above the bowl and the scale tool to size it. I’m also changing the Segments in X, Y and Z to 10. We’ll need this for our cube to deform.

To make the objects interact and respond to forces and collisions, we will give them Dynamics tags. Select the cube and apply a Soft Body tag. This tag is suitable for objects that deform on impact, like water balloons or Jell-O. After you apply a tag, you’ll see it show up in the Object Manager next to the object.

With the bowl selected, add a Collider tag. This is used on objects that you want to be a part of a simulation, but not to be moved by other objects. In our case, it is unlikely that Jell-O would be strong enough to move the bowl so we’re safe to use a Collider tag.

For proper simulation playback, we need to make sure that Cinema 4D is calculating every frame. Check that your playback is set to All Frames and then press the play button.

You should now see your cube fall and collide with the bowl. Upon collision, you should also notice the cube deforms. By default, the playback will only update in the active viewport (the one with the white outline). Oddly, it will appear as though the cube is hitting an invisible lid on the bowl.

In the bowl’s dynamics tag, we just need to change the Shape to Static Mesh. This will help to evaluate all surfaces of the bowl instead of just having it shrink wrapped like before. If all goes well, our cube should now be hitting the bottom of the bowl.

We’ll now adjust the settings of the cube’s Soft Body attributes. The help documents go in-depth as to what each value does. You may want to use my settings as a starting point and then experiment with other values that you may discover from there.

Now that we have a working simulation, we’ll duplicate our cube a few times by using Ctrl+LMB (Cmd+LMB) and dragging down its name in the Object Manager.

Move and rotate the cubes so that we have some variety in their starting positions. At the beginning of this process, make sure that you do not have any of them overlapping each other.

Due to the number of collisions happening, the scene will not play back at a usable speed. We’ll need to cache our cubes which will process the simulation, save that information and allow our playback to play better. To do this, select all of your cube’s Dynamics tags (hold Shift) and select Bake.

Once a simulation is baked, it no longer calculates on the fly. If you make changes to any of your dynamics settings, you’ll need to remember to come back to these tags and select Clear Cache. Play your simulation and make any adjustments you think are needed.

With our simulation complete, it is time to add materials. Cinema 4D ships with a decent amount of presets that you can use to get you started while you’re learning. In this example, I created a number of different materials.

Just like objects, materials can also be duplicated. I made a number of copies and changed each one’s settings. To apply the material, drag it onto the object in the viewport or onto its label in the Object Manager.

We’re now ready to render. I’ll switch to my ShotCam and move around to get a good view.

Now we will adjust our render settings. Ctrl+B (Cmd+B) will bring up your Render Settings window. We’ll first set the output (which controls the size of our rendered image) and whether we’re rendering a single frame or a sequence.

Then, we’ll set the location and name of the image that is rendered. Pick a location and file name that you’ll remember.

Adjust the anti-aliasing settings to the ones shown. This will help to smooth out jagged edges. If you’re rendering an animation, change the Filter to match.

Finally, activate Global Illumination by clicking on Effect > Global Illumination. For a still image, Sky Sampler works fairly well. If you’re rendering an animation, you’ll likely need to change to IR+QMC (Full Animation). When everything is set, hit Shift+R to admire your animation and newly acquired skills.

CONCLUSION

Now that you have seen the basics of what dynamic simulations can do, start experimenting for yourself. Any rigid or soft body can be simulated like this example. Try it with a set of billiard balls, rocks during a landslide or water balloons rolling down the stairs – the only limit is your creativity.

Click the video below to view the finished animation.