import bpy
from bpy.props import (StringProperty,
                   BoolProperty,
                   IntProperty,
                   FloatProperty,
                   EnumProperty,
                   PointerProperty
                   )
from bpy.types import (Panel,
                   Operator,
                   PropertyGroup
                   )

class MySettings(PropertyGroup):

path : StringProperty(
    name="path",
    description="Path to Directory",
    default="",
    maxlen=1024,
    subtype='DIR_PATH')

conform_threshold : FloatProperty(
    name="conform_threshold",
    description="A float property",
    default=0.1,
    min=-5,
    max=30.0)

invert : BoolProperty(
    name="Enable or Disable",
    description="A simple bool property",
    default = False)







class UI_PT_LynchonPanel(bpy.types.Panel):
"""Las super herramientas de Juan"""
bl_label = "Lynchon Tools"
bl_space_type = 'VIEW_3D'
bl_region_type = "UI"
bl_category = "Lynchon Tools"

def draw(self, context):

                                                ####################Y UP##################################
    layout = self.layout
    row = layout.row()
    row.operator("object.y_up")

     # Create two columns, by using a split layout.####################MET COMPILER##################################

    split = layout.split()
    # First column
    col = split.column()
    col.operator("texture.metal_compiler")

    scn = context.scene
    mytool = scn.my_tool
    col = split.column(align=True)
    col.prop(mytool, 'invert' ,text = "Invert")

    # Create two columns, by using a split layout. ####################LOW POLY VENUE##################################
    split = layout.split()

    # First column
    col = split.column()
    col.label(text="Import Venue")
    col.operator( "xml.lowpolygeneratorparticles")

    # Second column, aligned
    col = split.column(align=True)
    col.label(text="Conform Venue")
    col.operator( "xml.conform_lp_venue")

    # root for export
    scn = context.scene
    mytool = scn.my_tool
    col = layout.column(align=True)
    col.prop(mytool, "path", text="")

    # Create two columns, by using a split layout.  ####################CONFORM HEIGHT##################################
    split = layout.split()

    # First column
    col = split.column()
    col.operator("xml.conformheight")

    # Second column, aligned
    scn = context.scene
    mytool = scn.my_tool
    col = split.column(align=True)
    col.prop(mytool, "conform_threshold")



def register():

bpy.utils.register_class(UI_PT_LynchonPanel)
bpy.utils.register_class(MySettings)
bpy.types.Scene.my_tool = PointerProperty(type=MySettings)



def unregister():

bpy.utils.unregister_class(UI_PT_LynchonPanel)
bpy.utils.unregister_class(MySettings)
del bpy.types.Scene.my_tool

location: <unknown location>:-1
Traceback (most recent call last):
  File "C:UsersJuanAppDataRoamingBlender FoundationBlender2.80scriptsaddonsLynchon_tools280UI.py", line 63, in draw
    mytool = scn.my_tool
AttributeError: 'Scene' object has no attribute 'my_tool'