Create and edit nCloth collisions

Note

Turn on Use Plane in the nucleus Attribute Editor tab to enable floor collisions for your nCloth.
During simulation, Maya reduces the relative Collision Thickness (nClothShape node) of objects so that they do not overlap at the start frame. This avoids sudden popping at the start frame, but in some cases, may cause added friction. You cannot see the effects of the thickness reduction in the scene view. To avoid this, model the start state so that the surfaces with thickness do not overlap. In addition, you can use nSolver > Initial State > Resolve Interpenetration to fix subtle overlaps.

To create an nCloth collision object

In the scene view, select the polygon mesh you want to make an nCloth passive object.
Select the nCloth for which you want to create the passive object.
In the nDynamics menu set, select nMesh > Create Passive Collider.
The polygon mesh you created becomes a collision or passive object of the nCloth you selected. The passive object is connected to the nCloth’s Maya Nucleus solver through a nRigid node.

To set how your nCloth and passive objects collide

In the scene view, select the nCloth or passive object for which you want to edit its collisions.
In the Attribute Editor, select your nCloth (nClothShape) or passive (nRigidShape) object’s tab.
In the Collisions section, set the Collide Strength.
Collide Strength specifies the amount of force generated when nCloth or passive collision objects collide with other Nucleus objects. At the default value of 1, the objects fully collide with other Nucleus objects. Values between 0 and 1 dampen the full collision, while 0 turns off the object's collisions.
In the Quality Settings section, set the Collision Flag.
Collision Flag specifies the type of collision of your nCloth or passive object. For example, if you set Collision Flag to Face, then your nCloth or passive object’s collisions are tested for Faces only.

To produce good collisions, nCloth and passive objects that are part of the same Maya Nucleus system should have the same Collision Flag settings.

Setting collision layers

You can specify whether or not certain nCloth objects and passive objects that are part of the same Maya Nucleus system collide with each other by using collision layers. The Collision Layer attribute on your nClothShape node determines on which collision layer each nCloth and passive object is placed, and the Collision Layer Range attribute on your nucleus node determines how nCloths and passive objects on different layers collide. For more information on these collision layer attributes, see Collision Layer and Collision Layer Range.

Note

Passive objects in collision layers only collide with nCloth objects that are in the same collision layer, or in layers of higher value.

To stop nCloths, passive objects, or their components from colliding

You can use the Paint nCloth Attributes Tool to create a Collide Strength vertex map or texture map that dampens or disables collisions on nCloth and passive collision object components. See Paint nCloth property maps

Note

If you want to disable object components from collisions, ensure that areas are painted completely black. Use an Artisan brush with no dropoff, such as and ensure that the Opacity is set to 1.0. Areas of the nCloth or passive collision mesh that are shades of gray will collide.

You can also use a Disable Collision constraint to stop nCloth, passive objects, or their components from colliding. See Creating a Disable Collisions constraint.

To stop nCloths, passive objects, or their components from colliding with specific Maya Nucleus system members

See Creating an Exclude Collide Pairs constraint.

Increase the accuracy of your nCloth collisions

To increase the accuracy of your nCloth collisions

Select the nCloth or passive object for which you want to increase its accuracy and improve its collisions.
In the Attribute Editor do the following:
- Adjust the Thickness of your nCloth or passive object. Select the nClothShape or nRigidShape tabs, and in the Collisions section, change the Thickness value. For best results, the collision volume should appear to cling closely to your nCloth.
- Adjust the Self Collision Thickness of your nCloth object. Select the nClothShape tab, and in the Collisions section, change the Self Collide Width Scale value.
- Adjust the Collision Flag for your nCloth object. Select the nClothShape tab, and in the Collisions section, change the selection in the Collision Flag drop-down list. Face creates the most accurate collisions and Vertex creates the least accurate collisions.
- Adjust the Self Collision Flag for your nCloth. Select the nClothShape tab, and in the Collisions section, change the selection in the Self Collision Flag drop-down list.
- Increase the number of collide iterations for your nCloth by adjusting its Max Self Collide Iterations attribute in the Quality Settings section of its nucleus tab.
- Resolve interpenetration for your nCloth by adjusting its Trapped Check, Push Out, and Crossover Push attributes in the Quality Settings section of the nClothShape and nRigidShape tabs.