Getting Started

In this guide, we will use Dynamo to create a simple animation. You will learn how to use the fundamental components of Dynamo - the Dynamo modifier and the Dynamo solver object - to set up a cloth simulation.

Building the Scene

The scene will consist of a piece of fabric falling on the floor and the first step is to create object that will represent the fabric using a plane in 3ds Max.

Create a plane for the piece of fabric with

  • Length = 60 cm
  • Width = 200 cm
  • Length Segs = 30
  • Width Segs = 100

Note

The number of segments used here are proportional to the size of each side. This ensures that the faces will be even squares. When preparing meshes for use with Dynamo, it is worthwile to make sure that the faces are as evenly shaped as possible, since this will give a more believable result.

Rotate the piece of fabric -85 degrees along x, so that it is almost perpendicular to the ground, and move it up about 150cm in z.

Now, add a DynamoModifier to the piece of fabric. This will automatically create a DynamoSolver object in the scene and link the modifier to it. The solver is a helper object represented by the Deform Dynamics logo.

By default Dynamo will treat z=0 as a ground collider, meaning the fabric will fall on the floor. To disable the ground collision, click on the DynamoSolver object (the Dynamo logo) and uncheck "Ground collision". We will leave the "Ground collision" enabled for now.

Your scene should now look like the image below, and you are ready to start simulating.

Initial scene
The finished scene before simulation

Simulating the Fabric

The Dynamo modifier contains reasonable default values, so let's check out what the simulation looks like before tweaking anything.

Sim panel

Select the piece of fabric and press Bake in the rollup labeled Simulation on the command panel. The fabric should fall to the ground and bend under it's own weight, similar to the images below.

Note

The result might not look exactly like the images. There is a slight randomness in the simulation and therefore, two simulations will never look the same, even if they use exactly the same parameters.

Frame 18 Frame 100
The simulation at frame 18 The simulation at frame 100

When the simulation has finished baking, take a look at the Cache rollup. You will see that the simulation is now saved in the cache of the modifier. It's start and end frames are displayed, together with the amount of memory it uses. If you move the time slider in 3ds Max, the state of the cloth will be loaded from the cache for each frame.

Cache rollout

Bending Stiffness

To adjust the look of the fabric, increase the Bend stiffness in the Object rollup to 0.06 and press Bake again. You will notice that there are fewer wrinkles and that the fabric is stiffer overall. The bending stiffness is an important parameter to adjust when tweaking the look of a Dynamo simulation.

Frame 18 Frame 100
The simulation at frame 18 The simulation at frame 100

Solver Accuracy

Solver panel

In the Solver rollup, you will find several settings. The most important group of settings right now is Accuracy. Here, you will find a value called Max. stiffness, which is an upper limit on the bending and distance stiffness values of the object.

Try decreasing the value of Iterations to 1. Note that Max. stiffness is now 0.05 instead of 0.071. Press Bake again.

Frame 18 Frame 100
The simulation at frame 18 The simulation at frame 100

The cloth is now less stff again, even though we did not change the Bending stiffness. The reason for this is that when we lowered the number of Iterations, the maximum stiffness that the solver could acchieve dropped to 0.05 and thus, the effective bending stiffness became this value, rather than 0.071. Similarly, if we set the Bending stiffness 0.2, we would have to increase the number of Iterations or Substeps in the solver until the Max. stiffness was at least 0.2. The FPS set in the max timeline will also affect the max stiffness.

Note

To learn more about the Accuracy settings of the solver, check the relevant section of the manual.

Self Collisions

Now, try disabling Self collisions in the Solver rollup, under Colliders and see how it affects the simulation. Self collisions are enabled by default as they add a lot of realism to the simulations. Without them objects will not collide with themselves, and can create unrealistic intersections, as can be seen in the images below. However, disabling self collisions can lead to faster bake times and in some scenes the intersections are not as obvious as they are here.

Frame 18 Frame 100
The simulation at frame 18 The simulation at frame 100

Conclusion

Congratulations, you have finished your first simulation in Dynamo! To continue learning, check out the rest of the guides by pressing Next.