io_import_scene_mhx.py

    def draw(self, context):
        drawShapePanel(self, context, "Mhs", "expression")


class MhxCustomShapePanel(bpy.types.Panel):
    bl_label = "MHX Custom Shapes"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_options = {'DEFAULT_CLOSED'}

    @classmethod
    def poll(cls, context):
        return hasProps(context.object, "Mhc")

    def draw(self, context):
        drawShapePanel(self, context, "Mhc", "custom shape")


#########################################
#
#   FK-IK snapping.
#
#########################################

def getPoseMatrix(gmat, pb):
    restInv = pb.bone.matrix_local.inverted()
    if pb.parent:
        parInv = pb.parent.matrix.inverted()
        parRest = pb.parent.bone.matrix_local
        return restInv * (parRest * (parInv * gmat))
    else:
        return restInv * gmat


def getGlobalMatrix(mat, pb):
    gmat = pb.bone.matrix_local * mat
    if pb.parent:
        parMat = pb.parent.matrix
        parRest = pb.parent.bone.matrix_local
        return parMat * (parRest.inverted() * gmat)
    else:
        return gmat


def matchPoseTranslation(pb, src, auto):
    pmat = getPoseMatrix(src.matrix, pb)
    insertLocation(pb, pmat, auto)


def insertLocation(pb, mat, auto):
    pb.location = mat.to_translation()
    if auto:
        pb.keyframe_insert("location", group=pb.name)
    bpy.ops.object.mode_set(mode='OBJECT')
    bpy.ops.object.mode_set(mode='POSE')


def matchPoseRotation(pb, src, auto):
    pmat = getPoseMatrix(src.matrix, pb)
    insertRotation(pb, pmat, auto)


def printMatrix(string,mat):
    print(string)
    for i in range(4):
        print("    %.4g %.4g %.4g %.4g" % tuple(mat[i]))


def insertRotation(pb, mat, auto):
    q = mat.to_quaternion()
    if pb.rotation_mode == 'QUATERNION':
        pb.rotation_quaternion = q
        if auto:
            pb.keyframe_insert("rotation_quaternion", group=pb.name)
    else:
        pb.rotation_euler = q.to_euler(pb.rotation_mode)
        if auto:
            pb.keyframe_insert("rotation_euler", group=pb.name)
    bpy.ops.object.mode_set(mode='OBJECT')
    bpy.ops.object.mode_set(mode='POSE')


def matchIkLeg(legIk, toeFk, mBall, mToe, mHeel, auto):
    rmat = toeFk.matrix.to_3x3()
    tHead = Vector(toeFk.matrix.col[3][:3])
    ty = rmat.col[1]
    tail = tHead + ty * toeFk.bone.length

    try:
        zBall = mBall.matrix.col[3][2]
    except AttributeError:
        return
    zToe = mToe.matrix.col[3][2]
    zHeel = mHeel.matrix.col[3][2]

    x = Vector(rmat.col[0])
    y = Vector(rmat.col[1])
    z = Vector(rmat.col[2])

    if zHeel > zBall and zHeel > zToe:
        # 1. foot.ik is flat
        if abs(y[2]) > abs(z[2]):
            y = -z
        y[2] = 0
    else:
        # 2. foot.ik starts at heel
        hHead = Vector(mHeel.matrix.col[3][:3])
        y = tail - hHead

    y.normalize()
    x -= x.dot(y)*y
    x.normalize()
    z = x.cross(y)
    head = tail - y * legIk.bone.length

    # Create matrix
    gmat = Matrix()
    gmat.col[0][:3] = x
    gmat.col[1][:3] = y
    gmat.col[2][:3] = z
    gmat.col[3][:3] = head
    pmat = getPoseMatrix(gmat, legIk)

    insertLocation(legIk, pmat, auto)
    insertRotation(legIk, pmat, auto)


def matchPoleTarget(pb, above, below, auto):
    x = Vector(above.matrix.col[1][:3])
    y = Vector(below.matrix.col[1][:3])
    p0 = Vector(below.matrix.col[3][:3])
    n = x.cross(y)
    if abs(n.length) > 1e-4:
        z = x - y
        n = n/n.length
        z -= z.dot(n)*n
        p = p0 + z/z.length*3.0
    else:
        p = p0
    gmat = Matrix.Translation(p)
    pmat = getPoseMatrix(gmat, pb)
    insertLocation(pb, pmat, auto)


def matchPoseReverse(pb, src, auto):
    gmat = src.matrix
    tail = gmat.col[3] + src.length * gmat.col[1]
    rmat = Matrix((gmat.col[0], -gmat.col[1], -gmat.col[2], tail))
    rmat.transpose()
    pmat = getPoseMatrix(rmat, pb)
    pb.matrix_basis = pmat
    insertRotation(pb, pmat, auto)


def matchPoseScale(pb, src, auto):
    pmat = getPoseMatrix(src.matrix, pb)
    pb.scale = pmat.to_scale()
    if auto:
        pb.keyframe_insert("scale", group=pb.name)
    bpy.ops.object.mode_set(mode='OBJECT')
    bpy.ops.object.mode_set(mode='POSE')


def snapFkArm(context, data):
    rig = context.object
    prop,old,suffix = setSnapProp(rig, data, 1.0, context, False)
    auto = context.scene.tool_settings.use_keyframe_insert_auto

    print("Snap FK Arm%s" % suffix)
    snapFk,cnsFk = getSnapBones(rig, "ArmFK", suffix)
    (uparmFk, loarmFk, handFk) = snapFk
    muteConstraints(cnsFk, True)
    snapIk,cnsIk = getSnapBones(rig, "ArmIK", suffix)
    (uparmIk, loarmIk, elbow, elbowPt, handIk) = snapIk

    matchPoseRotation(uparmFk, uparmIk, auto)
    matchPoseScale(uparmFk, uparmIk, auto)

    matchPoseRotation(loarmFk, loarmIk, auto)
    matchPoseScale(loarmFk, loarmIk, auto)

    restoreSnapProp(rig, prop, old, context)

    try:
        matchHand = rig["MhaHandFollowsWrist" + suffix]
    except KeyError:
        matchHand = True
    if matchHand:
        matchPoseRotation(handFk, handIk, auto)
        matchPoseScale(handFk, handIk, auto)

    #muteConstraints(cnsFk, False)
    return


def snapIkArm(context, data):
    rig = context.object
    prop,old,suffix = setSnapProp(rig, data, 0.0, context, True)
    auto = context.scene.tool_settings.use_keyframe_insert_auto

    print("Snap IK Arm%s" % suffix)
    snapIk,cnsIk = getSnapBones(rig, "ArmIK", suffix)
    (uparmIk, loarmIk, elbow, elbowPt, handIk) = snapIk
    snapFk,cnsFk = getSnapBones(rig, "ArmFK", suffix)
    (uparmFk, loarmFk, handFk) = snapFk
    muteConstraints(cnsIk, True)

    matchPoseTranslation(handIk, handFk, auto)
    matchPoseRotation(handIk, handFk, auto)

    matchPoleTarget(elbowPt, uparmFk, loarmFk, auto)

    #matchPoseRotation(uparmIk, uparmFk, auto)
    #matchPoseRotation(loarmIk, loarmFk, auto)

    restoreSnapProp(rig, prop, old, context)
    #muteConstraints(cnsIk, False)
    return


def snapFkLeg(context, data):
    rig = context.object
    prop,old,suffix = setSnapProp(rig, data, 1.0, context, False)
    auto = context.scene.tool_settings.use_keyframe_insert_auto

    print("Snap FK Leg%s" % suffix)
    snap,_ = getSnapBones(rig, "Leg", suffix)
    (upleg, loleg, foot, toe) = snap
    snapIk,cnsIk = getSnapBones(rig, "LegIK", suffix)
    (uplegIk, lolegIk, kneePt, ankleIk, legIk, footRev, toeRev, mBall, mToe, mHeel) = snapIk
    snapFk,cnsFk = getSnapBones(rig, "LegFK", suffix)
    (uplegFk, lolegFk, footFk, toeFk) = snapFk
    muteConstraints(cnsFk, True)

    matchPoseRotation(uplegFk, uplegIk, auto)
    matchPoseScale(uplegFk, uplegIk, auto)

    matchPoseRotation(lolegFk, lolegIk, auto)
    matchPoseScale(lolegFk, lolegIk, auto)

    restoreSnapProp(rig, prop, old, context)

    if not rig["MhaLegIkToAnkle" + suffix]:
        matchPoseReverse(footFk, footRev, auto)
        matchPoseReverse(toeFk, toeRev, auto)

    #muteConstraints(cnsFk, False)
    return


def snapIkLeg(context, data):
    rig = context.object
    scn = context.scene
    prop,old,suffix = setSnapProp(rig, data, 0.0, context, True)
    auto = scn.tool_settings.use_keyframe_insert_auto

    print("Snap IK Leg%s" % suffix)
    snapIk,cnsIk = getSnapBones(rig, "LegIK", suffix)
    (uplegIk, lolegIk, kneePt, ankleIk, legIk, footRev, toeRev, mBall, mToe, mHeel) = snapIk
    snapFk,cnsFk = getSnapBones(rig, "LegFK", suffix)
    (uplegFk, lolegFk, footFk, toeFk) = snapFk
    muteConstraints(cnsIk, True)

    legIkToAnkle = rig["MhaLegIkToAnkle" + suffix]
    if legIkToAnkle:
        matchPoseTranslation(ankleIk, footFk, auto)

    #matchPoseTranslation(legIk, legFk, auto)
    #matchPoseRotation(legIk, legFk, auto)
    matchIkLeg(legIk, toeFk, mBall, mToe, mHeel, auto)

    matchPoseReverse(toeRev, toeFk, auto)
    matchPoseReverse(footRev, footFk, auto)

    matchPoleTarget(kneePt, uplegFk, lolegFk, auto)

    #matchPoseRotation(uplegIk, uplegFk, auto)
    #matchPoseRotation(lolegIk, lolegFk, auto)

    if not legIkToAnkle:
        matchPoseTranslation(ankleIk, footFk, auto)

    restoreSnapProp(rig, prop, old, context)
    #muteConstraints(cnsIk, False)
    return


SnapBonesAlpha8 = {
    "Arm"   : ["upper_arm", "forearm", "hand"],
    "ArmFK" : ["upper_arm.fk", "forearm.fk", "hand.fk"],
    "ArmIK" : ["upper_arm.ik", "forearm.ik", None, "elbow.pt.ik", "hand.ik"],
    "Leg"   : ["thigh", "shin", "foot", "toe"],
    "LegFK" : ["thigh.fk", "shin.fk", "foot.fk", "toe.fk"],
    "LegIK" : ["thigh.ik", "shin.ik", "knee.pt.ik", "ankle.ik", "foot.ik", "foot.rev", "toe.rev", "ball.marker", "toe.marker", "heel.marker"],
}


def getSnapBones(rig, key, suffix):
    try:
        pb = rig.pose.bones["UpLeg_L"]
    except KeyError:
        pb = None

    if pb is not None:
        raise NameError("MakeHuman alpha 7 not supported after Blender 2.68")

    try:
        rig.pose.bones["thigh.fk.L"]
        names = SnapBonesAlpha8[key]
        suffix = '.' + suffix[1:]
    except KeyError:
        names = None

    if not names:
        raise NameError("Not an mhx armature")

    pbones = []
    constraints = []
    for name in names:
        if name:
            try:
                pb = rig.pose.bones[name+suffix]
            except KeyError:
                pb = None
            pbones.append(pb)
            if pb is not None:
                for cns in pb.constraints:
                    if cns.type == 'LIMIT_ROTATION' and not cns.mute:
                        constraints.append(cns)
        else:
            pbones.append(None)
    return tuple(pbones),constraints


def muteConstraints(constraints, value):
    for cns in constraints:
        cns.mute = value


class VIEW3D_OT_MhxSnapFk2IkButton(bpy.types.Operator):
    bl_idname = "mhx.snap_fk_ik"
    bl_label = "Snap FK"
    bl_options = {'UNDO'}
    data = StringProperty()

    def execute(self, context):
        bpy.ops.object.mode_set(mode='POSE')
        rig = context.object
        if rig.MhxSnapExact:
            rig["MhaRotationLimits"] = 0.0
        if self.data[:6] == "MhaArm":
            snapFkArm(context, self.data)
        elif self.data[:6] == "MhaLeg":
            snapFkLeg(context, self.data)
        return{'FINISHED'}


class VIEW3D_OT_MhxSnapIk2FkButton(bpy.types.Operator):
    bl_idname = "mhx.snap_ik_fk"
    bl_label = "Snap IK"
    bl_options = {'UNDO'}
    data = StringProperty()

    def execute(self, context):
        bpy.ops.object.mode_set(mode='POSE')
        rig = context.object
        if rig.MhxSnapExact:
            rig["MhaRotationLimits"] = 0.0
        if self.data[:6] == "MhaArm":
            snapIkArm(context, self.data)
        elif self.data[:6] == "MhaLeg":
            snapIkLeg(context, self.data)
        return{'FINISHED'}


def setSnapProp(rig, data, value, context, isIk):
    words = data.split()
    prop = words[0]
    oldValue = rig[prop]
    rig[prop] = value
    ik = int(words[1])
    fk = int(words[2])
    extra = int(words[3])
    oldIk = rig.data.layers[ik]
    oldFk = rig.data.layers[fk]
    oldExtra = rig.data.layers[extra]
    rig.data.layers[ik] = True
    rig.data.layers[fk] = True
    rig.data.layers[extra] = True
    updatePose(context)
    if isIk:
        oldValue = 1.0
        oldIk = True
        oldFk = False
    else:
        oldValue = 0.0
        oldIk = False
        oldFk = True
        oldExtra = False
    return (prop, (oldValue, ik, fk, extra, oldIk, oldFk, oldExtra), prop[-2:])


def restoreSnapProp(rig, prop, old, context):
    updatePose(context)
    (oldValue, ik, fk, extra, oldIk, oldFk, oldExtra) = old
    rig[prop] = oldValue
    rig.data.layers[ik] = oldIk
    rig.data.layers[fk] = oldFk
    rig.data.layers[extra] = oldExtra
    updatePose(context)
    return


class VIEW3D_OT_MhxToggleFkIkButton(bpy.types.Operator):
    bl_idname = "mhx.toggle_fk_ik"
    bl_label = "FK - IK"
    bl_options = {'UNDO'}
    toggle = StringProperty()

    def execute(self, context):
        words = self.toggle.split()
        rig = context.object
        prop = words[0]
        value = float(words[1])
        onLayer = int(words[2])
        offLayer = int(words[3])
        rig.data.layers[onLayer] = True
        rig.data.layers[offLayer] = False
        rig[prop] = value
        # Don't do autokey - confusing.
        #if context.tool_settings.use_keyframe_insert_auto:
        #    rig.keyframe_insert('["%s"]' % prop, frame=scn.frame_current)
        updatePose(context)
        return{'FINISHED'}

#
#   MHX FK/IK Switch panel
#

class MhxFKIKPanel(bpy.types.Panel):
    bl_label = "MHX FK/IK Switch"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    #bl_options = {'DEFAULT_CLOSED'}

    @classmethod
    def poll(cls, context):
        return (context.object and context.object.MhxRig == 'MHX')

    def draw(self, context):
        rig = context.object
        layout = self.layout

        row = layout.row()
        row.label("")
        row.label("Left")
        row.label("Right")

        layout.label("FK/IK switch")
        row = layout.row()
        row.label("Arm")
        self.toggleButton(row, rig, "MhaArmIk_L", " 3", " 2")
        self.toggleButton(row, rig, "MhaArmIk_R", " 19", " 18")
        row = layout.row()
        row.label("Leg")
        self.toggleButton(row, rig, "MhaLegIk_L", " 5", " 4")
        self.toggleButton(row, rig, "MhaLegIk_R", " 21", " 20")

        layout.label("IK Influence")
        row = layout.row()
        row.label("Arm")
        row.prop(rig, '["MhaArmIk_L"]', text="")
        row.prop(rig, '["MhaArmIk_R"]', text="")
        row = layout.row()
        row.label("Leg")
        row.prop(rig, '["MhaLegIk_L"]', text="")
        row.prop(rig, '["MhaLegIk_R"]', text="")

        try:
            ok = (rig["MhxVersion"] >= 12)
        except:
            ok = False
        if not ok:
            layout.label("Snapping only works with MHX version 1.12 and later.")
            return

        layout.separator()
        layout.label("Snapping")
        row = layout.row()
        row.label("Rotation Limits")
        row.prop(rig, '["MhaRotationLimits"]', text="")
        row.prop(rig, "MhxSnapExact", text="Exact Snapping")

        layout.label("Snap Arm bones")
        row = layout.row()
        row.label("FK Arm")
        row.operator("mhx.snap_fk_ik", text="Snap L FK Arm").data = "MhaArmIk_L 2 3 12"
        row.operator("mhx.snap_fk_ik", text="Snap R FK Arm").data = "MhaArmIk_R 18 19 28"
        row = layout.row()
        row.label("IK Arm")
        row.operator("mhx.snap_ik_fk", text="Snap L IK Arm").data = "MhaArmIk_L 2 3 12"
        row.operator("mhx.snap_ik_fk", text="Snap R IK Arm").data = "MhaArmIk_R 18 19 28"

        layout.label("Snap Leg bones")
        row = layout.row()
        row.label("FK Leg")
        row.operator("mhx.snap_fk_ik", text="Snap L FK Leg").data = "MhaLegIk_L 4 5 12"
        row.operator("mhx.snap_fk_ik", text="Snap R FK Leg").data = "MhaLegIk_R 20 21 28"
        row = layout.row()
        row.label("IK Leg")
        row.operator("mhx.snap_ik_fk", text="Snap L IK Leg").data = "MhaLegIk_L 4 5 12"
        row.operator("mhx.snap_ik_fk", text="Snap R IK Leg").data = "MhaLegIk_R 20 21 28"


    def toggleButton(self, row, rig, prop, fk, ik):
        if rig[prop] > 0.5:
            row.operator("mhx.toggle_fk_ik", text="IK").toggle = prop + " 0" + fk + ik
        else:
            row.operator("mhx.toggle_fk_ik", text="FK").toggle = prop + " 1" + ik + fk


###################################################################################
#
#    Posing panel
#
###################################################################################
#
#    class MhxDriversPanel(bpy.types.Panel):
#

class MhxDriversPanel(bpy.types.Panel):
    bl_label = "MHX Drivers"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_options = {'DEFAULT_CLOSED'}

    @classmethod
    def poll(cls, context):
        return (context.object and context.object.MhxRig == 'MHX')

    def draw(self, context):
        lrProps = []
        props = []
        lrFaceProps = []
        faceProps = []
        plist = list(context.object.keys())
        plist.sort()
        for prop in plist:
            if prop[0:3] == 'Mha':
                if prop[-2:] == '_L':
                    lrProps.append(prop[:-2])
                elif prop[-2:] != '_R':
                    props.append(prop)
            elif prop[0:3] == 'Mhf':
                if prop[-2:] == '_L':
                    lrFaceProps.append(prop[:-2])
                elif prop[-2:] != '_R':
                    faceProps.append(prop)

        ob = context.object
        layout = self.layout
        for prop in props:
            layout.prop(ob, '["%s"]' % prop, text=prop[3:])

        layout.separator()
        row = layout.row()
        row.label("Left")
        row.label("Right")
        for prop in lrProps:
            row = layout.row()
            row.prop(ob, '["%s"]' % (prop+"_L"), text=prop[3:])
            row.prop(ob, '["%s"]' % (prop+"_R"), text=prop[3:])

        if faceProps:
            layout.separator()
            layout.label("Face shapes")
            for prop in faceProps:
                layout.prop(ob, '["%s"]' % prop, text=prop[3:])

            layout.separator()
            row = layout.row()
            row.label("Left")
            row.label("Right")
            for prop in lrFaceProps:
                row = layout.row()
                row.prop(ob, '["%s"]' % (prop+"_L"), text=prop[3:])
                row.prop(ob, '["%s"]' % (prop+"_R"), text=prop[3:])

        return

###################################################################################
#
#    Visibility panel
#
###################################################################################
#
#    class MhxVisibilityPanel(bpy.types.Panel):
#

class MhxVisibilityPanel(bpy.types.Panel):
    bl_label = "MHX Visibility"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_options = {'DEFAULT_CLOSED'}

    @classmethod
    def poll(cls, context):
        return (context.object and context.object.MhxRig)

    def draw(self, context):
        ob = context.object
        layout = self.layout
        props = list(ob.keys())
        props.sort()
        for prop in props:
            if prop[0:3] == "Mhh":
                layout.prop(ob, '["%s"]' % prop, text="Hide %s" % prop[3:])
        layout.separator()
        layout.operator("mhx.update_textures")
        layout.separator()
        layout.operator("mhx.add_hiders")
        layout.operator("mhx.remove_hiders")
        return

class VIEW3D_OT_MhxUpdateTexturesButton(bpy.types.Operator):
    bl_idname = "mhx.update_textures"
    bl_label = "Update"
    bl_options = {'UNDO'}

    def execute(self, context):
        scn = context.scene
        for mat in bpy.data.materials:
            if mat.animation_data:
                try:
                    mat["MhxDriven"]
                except:
                    continue
                for driver in mat.animation_data.drivers:
                    prop = mat.path_resolve(driver.data_path)
                    value = driver.evaluate(scn.frame_current)
                    prop[driver.array_index] = value
        return{'FINISHED'}

class VIEW3D_OT_MhxAddHidersButton(bpy.types.Operator):
    bl_idname = "mhx.add_hiders"
    bl_label = "Add Hide Property"
    bl_options = {'UNDO'}

    def execute(self, context):
        rig = context.object
        for ob in context.scene.objects:
            if ob.select and ob != rig:
                prop = "Mhh%s" % ob.name
                defNewProp(prop, "Bool", "default=False")
                rig[prop] = False
                addHider(ob, "hide", rig, prop)
                addHider(ob, "hide_render", rig, prop)
        return{'FINISHED'}

def addHider(ob, attr, rig, prop):
    fcu = ob.driver_add(attr)
    drv = fcu.driver
    drv.type = 'SCRIPTED'
    drv.expression = "x"
    drv.show_debug_info = True
    var = drv.variables.new()
    var.name = "x"
    targ = var.targets[0]
    targ.id = rig
    targ.data_path = '["%s"]' % prop
    return

class VIEW3D_OT_MhxRemoveHidersButton(bpy.types.Operator):
    bl_idname = "mhx.remove_hiders"
    bl_label = "Remove Hide Property"
    bl_options = {'UNDO'}

    def execute(self, context):
        rig = context.object
        for ob in context.scene.objects:
            if ob.select and ob != rig:
                ob.driver_remove("hide")
                ob.driver_remove("hide_render")
                del rig["Mhh%s" % ob.name]
        return{'FINISHED'}

###################################################################################
#
#    Common functions
#
###################################################################################
#
#   getMhxRigMesh(ob):
#

def pollMhx(ob):
    if not ob:
        return False
    elif ob.type == 'ARMATURE':
        return ob.MhxRig
    elif ob.type == 'MESH':
        par = ob.parent
        return (par and (par.type == 'ARMATURE') and par.MhxRig)
    else:
        return False

def getMhxRigMesh(ob):
    if ob.type == 'ARMATURE':
        for mesh in ob.children:
            if mesh.MhxMesh and ob.MhxRig:
                return (ob, mesh)
        return (ob, None)
    elif ob.type == 'MESH':
        par = ob.parent
        if (par and par.type == 'ARMATURE' and par.MhxRig):
            if ob.MhxMesh:
                return (par, ob)
            else:
                return (par, None)
        else:
            return (None, None)
    return (None, None)


#
#    setInterpolation(rig):
#

def setInterpolation(rig):
    if not rig.animation_data:
        return
    act = rig.animation_data.action
    if not act:
        return
    for fcu in act.fcurves:
        for pt in fcu.keyframe_points:
            pt.interpolation = 'LINEAR'
        fcu.extrapolation = 'CONSTANT'
    return

###################################################################################
#
#    initialize and register
#
###################################################################################

def menu_func(self, context):
    self.layout.operator(ImportMhx.bl_idname, text="MakeHuman (.mhx)...")

def register():
    bpy.types.Object.MhAlpha8 = BoolProperty(default=True)
    bpy.types.Object.MhxMesh = BoolProperty(default=False)
    bpy.types.Object.MhxRig = StringProperty(default="")
    bpy.types.Object.MhxVisemeSet = StringProperty(default="")
    bpy.types.Object.MhxRigify = BoolProperty(default=False)
    bpy.types.Object.MhxSnapExact = BoolProperty(default=False)
    bpy.types.Object.MhxShapekeyDrivers = BoolProperty(default=True)
    bpy.types.Object.MhxStrength = FloatProperty(
        name = "Expression strength",
        description = "Multiply expression with this factor",
        default=1.0, min=-1.0, max=2.0
        )
    bpy.utils.register_module(__name__)
    bpy.types.INFO_MT_file_import.append(menu_func)

def unregister():
    try:
        bpy.utils.unregister_module(__name__)
    except:
        pass
    try:
        bpy.types.INFO_MT_file_import.remove(menu_func)
    except:
        pass

if __name__ == "__main__":
    unregister()
    register()