The Cloth modifier is
the heart of the Cloth system, and is applied to all objects in
your scene that need to be part of the Cloth simulation. This is
where you define cloth and collision objects, assign properties,
and execute the simulation. Other controls include creating constraints,
interactively dragging the cloth, and erasing parts of the simulation.
Left: Cloth modifier
not yet applied
Right: Cloth modifier
applied and simulated
In a Cloth simulation,
you will let Cloth know which objects will be part of the simulation,
and which objects will not. Once you have done this, you define
what the objects are made of. You can specify what is made of cloth,
and what is a solid, collision object.
Because Cloth is a modifier,
an instance of it is assigned to each object to be included in the
Cloth simulation. This includes all cloth and collision objects.
Be aware that two cloth objects with two separate applications of
the Cloth modifier will not interact with one another. There are
a couple of ways to include objects in the simulation:
- Select all of the objects at once and
apply the Cloth modifier to them.
- Apply Cloth to one or more objects and
then add objects with the Add Objects button, available on both
the Object rollout and the
Units of Measure
ImportantThe following information
is necessary only if you change the system unit after applying the
Cloth modifier. If you change the system unit before applying Cloth,
the modifier automatically adjusts the cm/unit setting.
It is important to think
about size in doing clothing simulations. A very large flag behaves
differently from a handkerchief. If the scale is off, then the simulation
will be off. Because Cloth deals with real-world physics, it works
in real-world units. This means that Cloth needs to know the relationship
between units in 3ds Max Design and units in its own world.
For example, suppose
you create a plane that is 10 x 10 3ds Max Design units. If you want
this plane to behave like a 10-inch x 10-inch handkerchief, you
would tell Cloth that 1 3ds Max Design unit=1 inch. If you want it to
behave like a 10-foot x 10-foot bed sheet, you would tell Cloth
that 1 3ds Max Design unit=1 foot.
Except as noted at the
start of this section, Cloth ignores the 3ds Max Design System Units
Setup (under Customize menu Units
Units Setup). Cloth has its own units setup, which is determined
parameter on the Simulation Parameters
rollout. This tells Cloth how many centimeters (cm) correspond to
each 3ds Max Design unit. One inch equals 2.54 cm, so the default setting
of 2.54 means that one 3ds Max Design unit corresponds to 1 inch.
Following is the procedure
to follow to determine what setting to use here.
- Use the measure utility or tape helper
to measure some dimension of your cloth (or character) in 3ds Max Design units
(call this number x).
- Decide how big you want this object to
be in the real world Convert this number to centimeters. If you
have the dimension in inches, simply multiply by 2.54 (call this
Here is a quick example:
You import a file, man.obj, into 3ds Max Design, and
want to put a shirt on him.
- Using the Measure utility, you find that
the man is 170 3ds Max Design units tall. So y=170.
- You determine that this man is about
6 feet tall.
- 6 feet=72 inches.
- And 72 inches=72x2.54=182.88cm. So x=182.88
- So now you have the values to make sure
the shirt behaves correctly. Cm/unit=y/x=170/182.88=0.929. Or you
can round the spinner's value up to 1.0, since pinpoint accuracy
is not needed here.
Cloth provides many different
ways to set up fabric behaviors. You can make your cloth behave
like leather, silk, burlap, and anything in between.
Once all of your parameters
are set and you’re ready to go, it’s time to simulate. In many cases,
you will first perform a local simulation to fit your fabric to
your character. Once your fabric is in place, you can simulate over
Running a simulation
in Cloth is very freeform. You are able to make many changes and
edits to a simulation, making it more of a work in progress than
a click and a “hope for the best” scenario.
You can constrain fabric
in various ways to create different fabric effects during simulations.
Cloth can constrain cloth to have extra drag as it flies through
the air, or can cause it to be affected by a space warp in the scene.
Linking a portion of the fabric to an animated object or attaching
to a surface are other common constraints. If you wanted to create
a pair of pants you would constrain the top portion of the pants
to the waist of the character or a curtain can be constrained to
a rod. Constraints are a very important and robust part of Cloth.
Cloth has the ability to make multiple groups of constrained vertices
for great flexibility. You can constrain many different parts of
a piece of clothing to different nodes' surfaces or other cloth
You build constraints
in Cloth at the modifier's
At this level, you can see vertices of all selected objects, both
cloth and collision. You can then select these and place them in
groups. Once a group is defined, you can then attach or "constrain" the
selection set to another object, or have it affected by some external force.
You can tear cloth. For
an example of how to do so, see
Cloth tears during the
course of a simulation under a couple of circumstances:
You must specify where
the cloth will tear before you run the simulation. There are a few
different ways to do this:
Tearing Cloth and the Point
If you use a
Cache modifier to optimize a Cloth animation,
there is a chance that tears will not be smoothed correctly before
tearing occurs. To fix this problem, you can add a
modifier to the stack. Place the Welder above the
Point Cache modifier.
Example: To use the Keep Shape option:
If your cloth object
starts out with 3D shape that you'd like to retain during the simulation,
you can use the Keep Shape option and setting to preserve this shape,
or even reverse it. This simple procedure provides an example of
how to use Keep Shape.
- In the Top or Perspective viewport, create
a Plane primitive object of about 90 x 90 units, with 20 x 20 segments.
- Apply a Bend modifier, set Angle to 250.0,
and set Bend Axis to X.
This produces the initial
- Copy the bent plane twice so you have
three planes in a row. Rename the planes as follows:
- don't keep shape
- keep shape
- reverse shape
- Select all three planes
and apply the Cloth modifier.
- On the Simulation Parameters rollout,
turn off Gravity and set cm/unit to 0.5.
Turning off Gravity keeps
the cloth objects from falling during the simulation, so they stay
in view, and lowering the cm/unit setting compensates for the planes'
relatively large size.
- On the Object rollout, click Object Properties.
This opens the Object
- In the Objects In Simulation list, highlight
all three planes (by dragging), and then, above the Cloth Properties
group, choose Cloth. Also set U Bend to 500.0.
This also sets V Bend
to 500.0 automatically.
Using high Bend values
allows the simulation to proceed more quickly.
Next, you'll set different
Keep Shape properties separately for each object.
- Highlight the reverse shape object in
the list and set the Bend % value to –100.0.
NoteThe default value
- Click OK to exit the dialog.
- Select the don't keep shape object and
note that Object rollout Selected
Objects Manip group Use
Target State is off.
- Select both the reverse shape and
the keep shape objects, but not don't
keep shape, and then turn on Use Target State.
- On the Object rollout, click Simulate
After a few seconds,
the don't keep shape object starts
to flatten out, the keep shape object doesn't change,
and the reverse shape object has, in fact,
reversed its shape, effectively creating a negative bend angle.
TipYou can also use
Use Target State with Grab State to maintain or reverse a shape
created with a previous cloth simulation or shape-changing modifier.
Example: To tear a piece of cloth:
- In the Top viewport, create a Plane. Make it
about 150 units on each side. Set its Length
Segments and Width Segments both equal to 7.
- Also in the Top viewport, create two Dummy objects: one on each
side of the plane.
The plane flanked by
two dummy objects
- Turn on (Auto Key). Go to frame
100, then animate each dummy object so it moves about 300 units
away from the plane along its X axis: Move the left-hand dummy to the
left, and the right-hand dummy to the right.
- Turn off (Auto Key).
- Go back to Frame 0.
- Select the plane. Go to
the Modify panel, and apply
a Cloth modifier to the plane.
- On the Object rollout, click Object Properties. 3ds Max Design opens
the Object Properties dialog for cloth. In the list of objects,
click Plane01 to highlight it, choose
the Cloth radio button to make Plane01 behave
as cloth, and then click OK (keep all the default Cloth Property
- In the Modifier stack, go to the Group
- Select the vertices along
the left-hand side of the plane, and then on the Group rollout,
click Make Group. Click OK to accept the default name of Group01.
With Group01 still highlighted in the
Group list, click Node, and then in a viewport click the left-hand
dummy object to assign it to this group.
- Repeat step 9 for the right-hand column
of vertices and the right-hand dummy object.
- Select the two center columns
of plane vertices, and then on the Group rollout, click Make Tear.
Click OK to accept the default name of Group03.
Central vertices selected
to create a tear in the cloth
3ds Max Design creates a
new Weld constraint that comprises the vertices at the center of
the cloth plane.
After clicking Make
- On the Modifier stack, go back to the
top Cloth level.
- In the Object rollout Simulation group, click Simulate.
3ds Max Design animates the
dummies pulling at the cloth. As this happens, the cloth tears along
the vertices that you set to tear.
Cloth tearing in the
center as its edges are pulled apart
Depending on the position
of the dummy objects, the tear you see in your example might differ
from the one shown in these illustrations.
To run a cloth simulation with a networked
A complex cloth simulation
can require extensive computation and take a long time. Cloth includes
commands that make it easy to run a simulation on a networked machine
(part of a render farm), freeing up your machine for working on
other parts of the scene.
- Set up the simulation.
- For each cloth object in the simulation, select the object, and then
on the Selected Object rollout click Set and specify a path and
file name for the cache.
For best results, specify
a mapped drive and turn on Force UNC Path. This specifies the path
using the Universal Naming Convention so that it can be found by
all computers in the network. Also, it's probably a good idea to
keep all the cache files in the same directory.
- On the Simulation Parameters rollout,
turn on Sim On Render.
- Save the scene file.
- On the Render Setup dialog, turn on Net
Render, and then click Render. Submit the job to a single Server.
Unlike rendering, network
Cloth simulation cannot be split up among multiple Server machines.
NoteYou needn't render
the entire animation to trigger the cache creation; a single frame
As soon as the Server
machine starts the render, it begins computing the simulation and
saving it to disk. At any point you can load the simulation in its
current state from the cache file to check its progress by clicking
the Load button.
- Object Rollout (Cloth)
The Object rollout is
the first rollout you see on the Command panel once you apply the
Cloth modifier. It comprises mostly controls to create a Cloth simulation
and adjust fabric properties.
- Selected Object Rollout
The Selected Object
rollout lets you control the simulation caches, control and optionally
animate the cloth properties with a texture map or interpolation,
and specify a bend map. This rollout appears only when a single
object in the simulation is selected.
- Simulation Parameters Rollout (Cloth)
The Simulation Parameters
rollout settings let you specify general properties of the simulation
such as gravity, start and end frames, and sewing-spring options.
These settings apply to the simulation on a global scale, that is,
to all objects in the simulation.
- Group Sub-Object Level
Groups let you select
groups of vertices and constrain them to surfaces, collision objects,
or other cloth objects.
- Panel Sub-Object Level
At the Panel sub-object
level, you can select one panel (cloth section) at a time and change
its cloth properties.
- Seams Sub-Object Level
The Seams sub-object
rollout is used to define seam properties.
- Faces Sub-Object Level
The Faces sub-object
rollout enables interactive dragging of cloth objects while they
are simulated locally. This sub-object level is useful for positioning
cloth within your scenes in a more interactive way.