helixCmd.py

#-
# ==========================================================================
# Copyright (C) 1995 - 2006 Autodesk, Inc. and/or its licensors.  All 
# rights reserved.
#
# The coded instructions, statements, computer programs, and/or related 
# material (collectively the "Data") in these files contain unpublished 
# information proprietary to Autodesk, Inc. ("Autodesk") and/or its 
# licensors, which is protected by U.S. and Canadian federal copyright 
# law and by international treaties.
#
# The Data is provided for use exclusively by You. You have the right 
# to use, modify, and incorporate this Data into other products for 
# purposes authorized by the Autodesk software license agreement, 
# without fee.
#
# The copyright notices in the Software and this entire statement, 
# including the above license grant, this restriction and the 
# following disclaimer, must be included in all copies of the 
# Software, in whole or in part, and all derivative works of 
# the Software, unless such copies or derivative works are solely 
# in the form of machine-executable object code generated by a 
# source language processor.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND. 
# AUTODESK DOES NOT MAKE AND HEREBY DISCLAIMS ANY EXPRESS OR IMPLIED 
# WARRANTIES INCLUDING, BUT NOT LIMITED TO, THE WARRANTIES OF 
# NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR 
# PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE, OR 
# TRADE PRACTICE. IN NO EVENT WILL AUTODESK AND/OR ITS LICENSORS 
# BE LIABLE FOR ANY LOST REVENUES, DATA, OR PROFITS, OR SPECIAL, 
# DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES, EVEN IF AUTODESK 
# AND/OR ITS LICENSORS HAS BEEN ADVISED OF THE POSSIBILITY 
# OR PROBABILITY OF SUCH DAMAGES.
#
# ==========================================================================
#+

#
#   Creation Date:   2 October 2006
#
#   Description:
#
#       Creates a NURBS curve in the shape of a helix
#
#   Options:
#
#       p=#     The pitch of the helix, default to 0.5
#       r=#     The radius of the helix, default to 4.0
#
#   Example:
#
#       From Python:
#           import maya
#           maya.cmds.spHelix(p=0.3, r=7)
#
#       From Mel:
#           spHelix -p 0.3 -r 7
#

import maya.OpenMaya as OpenMaya
import maya.OpenMayaMPx as OpenMayaMPx
import sys, math

kPluginCmdName="spHelix"

kPitchFlag = "-p"
kPitchLongFlag = "-pitch"
kRadiusFlag = "-r"
kRadiusLongFlag = "-radius"

# command
class scriptedCommand(OpenMayaMPx.MPxCommand):
    def __init__(self):
        OpenMayaMPx.MPxCommand.__init__(self)
    
    def doIt(self, args):
        deg = 3
        ncvs = 20
        spans = ncvs - deg
        nknots = spans+2*deg-1
        radius = 4.0
        pitch = 0.5
        
        # Parse the arguments.
        argData = OpenMaya.MArgDatabase(self.syntax(), args)
        if argData.isFlagSet(kPitchFlag):
            pitch = argData.flagArgumentDouble(kPitchFlag, 0)
        if argData.isFlagSet(kRadiusFlag):
            radius = argData.flagArgumentDouble(kRadiusFlag, 0)

        controlVertices = OpenMaya.MPointArray()
        knotSequences = OpenMaya.MDoubleArray()

        # Set up cvs and knots for the helix
        #
        for i in range(0, ncvs):
            controlVertices.append( OpenMaya.MPoint( radius * math.cos(i),
                pitch * i, radius * math.sin(i) ) )

        for i in range(0, nknots):
            knotSequences.append( i )
        
        # Now create the curve
        #
        curveFn = OpenMaya.MFnNurbsCurve()
        
        nullObj = OpenMaya.MObject()

        try:
            # This plugin normally creates the curve by passing in the
            # cv's.  A function to create curves by passing in the ep's
            # has been added.  Set this to False to get that behaviour.
            #
            if True:
                curveFn.create( controlVertices,
                                knotSequences, deg, 
                                OpenMaya.MFnNurbsCurve.kOpen, 
                                0, 0, 
                                nullObj )
            else:
                curveFn.createWithEditPoints(controlVertices,
                                3, OpenMaya.MFnNurbsCurve.kOpen,
                                False, False, False)
        except:
            sys.stderr.write( "Error creating curve.\n" )
            raise

# Creator
def cmdCreator():
    # Create the command
    return OpenMayaMPx.asMPxPtr( scriptedCommand() )

# Syntax creator
def syntaxCreator():
    syntax = OpenMaya.MSyntax()
    syntax.addFlag(kPitchFlag, kPitchLongFlag, OpenMaya.MSyntax.kDouble)
    syntax.addFlag(kRadiusFlag, kRadiusLongFlag, OpenMaya.MSyntax.kDouble)
    return syntax

# Initialize the script plug-in
def initializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject, "Autodesk", "1.0", "Any")
    try:
        mplugin.registerCommand( kPluginCmdName, cmdCreator, syntaxCreator )
    except:
        sys.stderr.write( "Failed to register command: %s\n" % kPluginCmdName )
        raise

# Uninitialize the script plug-in
def uninitializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.deregisterCommand( kPluginCmdName )
    except:
        sys.stderr.write( "Failed to unregister command: %s\n" % kPluginCmdName )
        raise