preliminary_edge_length addon

edge_length_addon.py

bl_info = {
    "name": "Edge sum",
    "author": "zeffii",
    "version": (0, 1, 0),
    "blender": (2, 7, 7),
    "location": "3d view, N panel",
    "description": "Adds edge sum box to Mesh Display.",
    "wiki_url": "",
    "tracker_url": "",
    "category": "3D View"}

# http://blender.stackexchange.com/a/1071/47
# where Adhi suggests the space_view3d_panel_measure import.

import bpy
import bmesh
import space_view3d_panel_measure as pm


def print_details(num_edges, edge_length):
    print("number of edges: {0}".format(num_edges))
    print("combined length: {0:6f}".format(edge_length))


def get_combined_length(object_reference):

    # Get a BMesh representation
    bm = bmesh.from_edit_mesh(object_reference.data)

    selected_edges = [edge for edge in bm.edges if edge.select]
    num_edges = len(selected_edges)

    edge_length = 0
    for edge in selected_edges:
        edge_length += edge.calc_length()
         
    print_details(num_edges, edge_length)
    return round(edge_length, 6)
    

class SumButton(bpy.types.Operator):
    bl_idname = "scene.calculate_length"
    bl_label = "Sometype of operator"

    bpy.types.Scene.sum_addon_length = bpy.props.StringProperty(name = "")
 
    def execute(self, context):
        obj_reference = context.active_object
        length = get_combined_length(obj_reference)
        
        uinfo = pm.getUnitsInfo()    
        length = pm.convertDistance(length, uinfo)
        context.scene.sum_addon_length = length
        return{'FINISHED'}

class CopyLength(bpy.types.Operator):
    bl_idname = "scene.copy_length"
    bl_label = "copy to clipboard"
 
    def execute(self, context):
        context.window_manager.clipboard  = context.scene.sum_addon_length
        return{'FINISHED'}


def draw_item(self, context):
    layout = self.layout
    obj = context.object
    row = layout.row()
    scn = context.scene

    # display label and button
    if obj:
        row.label(text="summed edge length:")
        row = layout.row()
        
        split = row.split(percentage=0.50)
        col = split.column()
        col.prop(scn, 'sum_addon_length')

        split = split.split()
        col = split.column()
        col.operator("scene.calculate_length", text='Sum')

        split = split.split()
        col = split.column()
        col.operator("scene.copy_length", text='Copy')


def register():
    bpy.utils.register_module(__name__)
    bpy.types.VIEW3D_PT_view3d_meshdisplay.append(draw_item)

def unregister():
    bpy.utils.unregister_module(__name__)
    bpy.types.VIEW3D_PT_view3d_meshdisplay.remove(draw_item)

if __name__ == "__main__":
    register()

Excellent! Just what I was looking for the whole day! Thanks dude!

Excellent!
But!!! Dont work in 2.75 and dont calculate summed select area poligons

@mazeto @Spirit412 What errors are you getting?

@Spirit412 -- it isn't designed to calculate selected polygon area, but it would be easy to add.

I cannot install your addon with Blender 2.77
This is my screenshot.
Thank you.

I'm getting a similar error as thuydtd. It looks as though 'Edge Length' depended on 'View3D Measure Panel', which was removed because it was broken.

@zeffii, Is there any chance 'Edge Length' will be updated? I've been using it for making accurate measurements of body parts on character meshes, for clothing design.

This is not working for 2.77c, is there any chance that this will be updated ?