space_view3d_panel_measure.py

# ##### BEGIN GPL LICENSE BLOCK #####
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####
#
# Uses volume calculation and manifold check code (GPL2+) from:
# http://www.shapeways.com/forum/index.php?t=msg&goto=3639
# Shapeways Volume Calculator by Benjamin Lauritzen (Loonsbury)
#
# #################################

bl_info = {
    "name": "Measure Panel",
    "author": "Buerbaum Martin (Pontiac), TNae (Normal patch), "
              "Benjamin Lauritzen (Loonsbury; Volume code), "
              "Alessandro Sala (patch: Units in 3D View), "
              "Daniel Ashby (callback removal code) ",
    "version": (0, 9, 1),
    "blender": (2, 74, 0),
    "location": "View3D > Properties > Measure Panel",
    "description": "Measure distances between objects",
    "warning": "Disable during Render. Broken register",
    "tracker_url": "https://developer.blender.org/maniphest/task/edit/form/2/",
    "wiki_url": "http://wiki.blender.org/index.php/Extensions:2.6/Py/"
                "Scripts/3D_interaction/Panel_Measure",
    "category": "3D View",
}

"""
Measure panel

This script displays in OBJECT MODE:
* The distance of the 3D cursor to the origin of the
  3D space (if NOTHING is selected).
* The distance of the 3D cursor to the center of an object
  (if exactly ONE object is selected).
* The distance between 2 object centers
  (if exactly TWO objects are selected).
* The surface area of any selected mesh object.
* The average normal of the mesh surface of any selected mesh object.
* The volume of any selected mesh object.

Display in EDIT MODE (Local and Global space supported):
* The distance of the 3D cursor to the origin
  (in Local space it is the object center instead).
* The distance of the 3D cursor to a selected vertex.
* The distance between 2 selected vertices.

Usage:

This functionality can be accessed via the
"Properties" panel in 3D View ([N] key).

It's very helpful to use one or two "Empty" objects with
"Snap during transform" enabled for fast measurement.

More links:
http://gitorious.org/blender-scripts/blender-measure-panel-script
http://blenderartists.org/forum/showthread.php?t=177800
"""

import bpy
from bpy.props import *
from bpy.app.handlers import persistent
from mathutils import Vector, Matrix
import bgl
import blf
from bpy_extras.view3d_utils import location_3d_to_region_2d
from bpy_extras.mesh_utils import ngon_tessellate


# Precicion for display of float values.
PRECISION = 5

# Name of the custom properties as stored in the scene.
COLOR_LOCAL = (1.0, 0.5, 0.0, 0.8)
COLOR_GLOBAL = (0.5, 0.0, 1.0, 0.8)

# 3D View - text offset
OFFSET_LINE = 10   # Offset the text a bit to the right.
OFFSET_Y = 15      # Offset of the lines.
OFFSET_VALUE = 30  # Offset of value(s) from the text.

# 3D View - line width
LINE_WIDTH_XYZ = 1
LINE_WIDTH_DIST = 2


# Returns a tuple describing the current measuring system
# and formatting options.
# Returned data is meant to be passed to formatDistance().
# Original by Alessandro Sala (Feb, 12th 2012)
# Update by Alessandro Sala (Dec, 18th 2012)
def getUnitsInfo():
        scale = bpy.context.scene.unit_settings.scale_length
        unit_system = bpy.context.scene.unit_settings.system
        separate_units = bpy.context.scene.unit_settings.use_separate
        if unit_system == 'METRIC':
                scale_steps = ((1000, 'km'), (1, 'm'), (1 / 100, 'cm'),
                    (1 / 1000, 'mm'), (1 / 1000000, '\u00b5m'))
        elif unit_system == 'IMPERIAL':
                scale_steps = ((5280, 'mi'), (1, '\''),
                    (1 / 12, '"'), (1 / 12000, 'thou'))
                scale /= 0.3048  # BU to feet
        else:
                scale_steps = ((1, ' BU'),)
                separate_units = False

        return (scale, scale_steps, separate_units)


# Converts a distance from BU into the measuring system
# described by units_info.
# Original by Alessandro Sala (Feb, 12th 2012)
# Update by Alessandro Sala (Dec, 18th 2012)
def convertDistance(val, units_info):
        scale, scale_steps, separate_units = units_info
        sval = val * scale
        idx = 0
        while idx < len(scale_steps) - 1:
                if sval >= scale_steps[idx][0]:
                        break
                idx += 1
        factor, suffix = scale_steps[idx]
        sval /= factor
        if not separate_units or idx == len(scale_steps) - 1:
                dval = str(round(sval, PRECISION)) + suffix
        else:
                ival = int(sval)
                dval = str(round(ival, PRECISION)) + suffix
                fval = sval - ival
                idx += 1
                while idx < len(scale_steps):
                        fval *= scale_steps[idx - 1][0] / scale_steps[idx][0]
                        if fval >= 1:
                                dval += ' ' \
                                    + ("%.1f" % fval) \
                                    + scale_steps[idx][1]
                                break
                        idx += 1

        return dval


# Returns a single selected object.
# Returns None if more than one (or nothing) is selected.
# Note: Ignores the active object.
def getSingleObject():
    if len(bpy.context.selected_objects) == 1:
        return bpy.context.selected_objects[0]

    return None


# Returns a list with 2 3D points (Vector) and a color (RGBA)
# depending on the current view mode and the selection.
def getMeasurePoints(context):
    sce = context.scene
    mode = context.mode

    # Get a single selected object (or nothing).
    obj = getSingleObject()

    if mode == 'EDIT_MESH':
        obj = context.active_object

        if obj and obj.type == 'MESH' and obj.data:
            # Get mesh data from Object.
            mesh = obj.data

            # Get the selected vertices.
            # @todo: Better (more efficient) way to do this?
            verts_selected = [v for v in mesh.vertices if v.select == 1]

            if len(verts_selected) == 0:
                # Nothing selected.
                # We measure the distance from...
                # local  ... the object center to the 3D cursor.
                # global ... the origin to the 3D cursor.
                cur_loc = sce.cursor_location
                obj_loc = obj.matrix_world.to_translation()

                # Convert to local space, if needed.
                if measureLocal(sce):
                    p1 = cur_loc
                    p2 = obj_loc
                    return (p1, p2, COLOR_GLOBAL)