Overview

Create collision detection using expression node.

It is created only with expression node of Maya standard function. No plug-in node or other installation is required.

Tested with :

• Maya 2020 (Python2.7)
• Maya 2022 (Python3.7)
• Maya 2019 and below are not supported

Example of capsule collider :

Supported colliders

• Infinite Plane
• Sphere
• Capsule
• Capsule2 (radius individually)

Installation

Please do one of the following:

• Copy the expCol directory into the C:\Users\<username>\Documents\maya\scripts.
• Add the parent directory of expCol to PYTHONPATH environment variable.
• Add the parent directory of expCol to PYTHONPATH in Maya.env.

Usage

Create Collider

from expCol import collider

collider.iplane()
collider.sphere()
collider.capsule()
collider.capsule2()

Create Detection

from expCol import detection

detection.create('parent', 'input', 'output', 'controller', colliders=collider_list, groundCol=True)

• parent : Parent 'transform'.
• input : Child 'transform' before correction.
• output : Child 'transform' after correction.

  For more information on parent, input and output, please click here.

• controller : Any node to add attributes for control.
• colliders : Name array of colliders created.
• groundCol : Add horizontal plane collision. (*optional)

Example

import maya.cmds as cmds
from expCol import collider, detection

# sample joint chain
rootCtl = cmds.createNode('transform', n='rootCtl')
jointList = []
for i in range(4):
    roz = 0 if i else -90
    jointList.append(cmds.joint(n='joint_{}'.format(i), p=[0,-i*3,0], o=[0,0,roz]))
cmds.setAttr(rootCtl+'.ty', 10)

for i in range(len(jointList)-1):
    p = cmds.listRelatives(jointList[i], p=1)[0]
    pos1 = cmds.xform(jointList[i], q=1, ws=1, t=1)
    pos2 = cmds.xform(cmds.listRelatives(jointList[i],c=1)[0], q=1, ws=1, t=1)
    prt = cmds.createNode('transform', n='parent_{}'.format(i), p=p)
    ipt = cmds.createNode('transform', n='input_{}'.format(i), p=p)
    out = cmds.createNode('transform', n='output_{}'.format(i), p=p)
    cmds.xform(prt, ws=1, t=pos1)
    cmds.xform(ipt, ws=1, t=pos2)
    cmds.xform(out, ws=1, t=pos2)
    cmds.aimConstraint(out, jointList[i], u=[0,0,1], wu=[0,0,1], wut='objectrotation', wuo=prt)


# Create Colliders
collider_list = []
collider_list.append(collider.iplane())
collider_list.append(collider.capsule())

# Create Detections
for i in range(len(jointList)-1):
    detection.create('parent_{}'.format(i), 
                    'input_{}'.format(i), 
                    'output_{}'.format(i), 
                    'rootCtl', 
                    colliders=collider_list, 
                    groundCol=True)

Note

• A large number of detections can be very heavy.
• The number of colliders cannot be changed after a detection (expression node) is created.
• Scale is not supported.