GM Drop To Floor.py

import maya.api.OpenMaya as api
from maya import cmds
import math

# drop the selected objects to the ground with offset
def dropToFloor(nodes=None, offset=0):
    # no object is selected, return error
    if not nodes:
        nodes = cmds.ls(sl=True)

    if not nodes:
        cmds.error("No object is selected")

    # for loop for each object
    for node in nodes:
        # get the bounding box
        bbox = cmds.exactWorldBoundingBox(node)

        # store minimum y value
        minValue = bbox[1]

        # get world coordinate of the object
        ws = cmds.xform(node, q=True, t=True, ws=True)
        
        # calculate the difference between the floor with offset
        distance = ws[1] - bbox[1] + float(offset)
        ws[1] = distance

        # move the object
        cmds.xform(node, translation=ws, ws=True)
        
# window class to open window
# call this class to run the script
class Window(object):
    def __init__(self):
        self.name = 'GEMDropToFloor'
        # close the current window if the same name window exists
        if cmds.window(self.name, q=True, exists=True):
            cmds.deleteUI(self.name)

        # open window
        window = cmds.window(self.name, title='GEM Drop To Floor')
        # build UI
        self.buildUI()
        # show window
        cmds.showWindow()        
        cmds.window(window, edit=True, height=70, width=100)

    # UI implementation
    def buildUI(self):
        # set up column
        column = cmds.columnLayout(adjustableColumn=True, columnAttach=("both", 10), rowSpacing=4)

        # offset value input box
        self.offset = cmds.intSliderGrp(label="Offset", field=True)
        # Run button
        cmds.button(label="Drop", command=self.onApplyClick)

    def onApplyClick(self, *args):
        dropToFloor(offset=cmds.intSliderGrp(self.offset, query=True, value=True))
        #cmds.deleteUI(self.name)

Window()