This script uses graphviz to create diagrams from a Power BI project

CreateDiagram.py

# Code provided "as-is". Use at your own risk
# 
# Requires graphviz python package:
# pip install graphviz
# 
# Unless you run with the -s option, you must also install the graphviz software from
# https://www.graphviz.org/download/
#  
# Basic use: python CreateDiagram.py <path to folder with .SemanticModel>
# 
# For advanced options: python CreateDiagram.py -h
#

import json
import graphviz
import argparse
import os

def load_diagrams (basefolder):
    diagrams_folder = basefolder + "/diagramLayout.json"
    f_diagrams = open(diagrams_folder)
    diagrams = json.load(f_diagrams)
    diags = {}
    for it in diagrams["diagrams"]:
        name = it["name"]    
        nodes = it["nodes"]
        tables = [node["nodeIndex"] for node in nodes]
        diags[name] =tables
    return diags


def load_table (basefolder, tablename):
    table_file = f"{basefolder}/definition/tables/{tablename}.tmdl"
    tabletmdl = open(table_file).readlines()
    collist = []
    for l in tabletmdl:
        if l.strip().startswith("column "):
            if l.rfind("=") > -1:
                # calculated column with formula, only name is copied
                collist.append(l[l.find("column")+6:l.rfind("=")].strip())
            else:
                collist.append(l[l.find("column")+6:].strip())
    return collist


def load_relationships (basefolder):
    relationship_folder = basefolder + "/definition/relationships.tmdl"
    f_relationships = open(relationship_folder)
    relationships = f_relationships.readlines()

    rellist = []
    isactive = True
    crossfilter = False
    tomany = False
    for l in relationships:
        if l.lstrip().startswith("crossFilteringBehavior: bothDirections"):
            crossfilter = True
        if l.lstrip().startswith("toCardinality: many"):
            tomany = True
        if l.lstrip().startswith("isActive: false"):
            isactive = False
        if l.lstrip().startswith("fromColumn:"):
            starttable = l[l.find(": ")+2:l.find(".")].strip()
            startcol = l[l.find(".")+1:].strip()
        if l.lstrip().startswith("toColumn:"):
            endtable = l[l.find(": ")+2:l.find(".")].strip()
            endcol = l[l.find(".")+1:].strip()
            rellist.append((starttable,startcol,endtable, endcol,isactive,crossfilter,tomany))
            isactive = True
            crossfilter = False
            tomany = False
    return rellist     


parser=argparse.ArgumentParser(prog="CreateDiagram", description="Create simple diagrams from Power BI Project folder.\nProvide the path to the .SemanticModel folder, and optionally choose the desired graphic format.")
parser.add_argument("folder", help="Path to the <projectname>.SemanticModel folder of your Power BI Project. This folder is normally in the same folder where the .pbip file is stored.")
parser.add_argument("-f", "--format", default="svg", help="Graphic render format (gif, png, jpg, pdf, bmp, tif, webp, svg), defaults to svg")
parser.add_argument("-s", "--skiprender", help="Skip rendering the diagrams", action='store_true')
parser.add_argument("-r","--renderfolder", default=os.getcwd(), help=f"Folder where output files are produced. Defaults to {os.getcwd()}")
parser.add_argument("-m","--onlymain", action='store_true', help="Skip generating subdiagrams")
parser.add_argument("-i","--inactive", action='store_true', help="Also include inactive relationships in the diagram")
parser.add_argument("-b", "--generatebus", action="store_true", help="Generate a csv file with a data warehouse bus, using heuristics to determine facts and dimensions")
parser.add_argument("-c", "--showcardinality", action="store_true", help="Display cardinality on edges")
args=parser.parse_args()

folderpath = args.folder.replace("\\","/").rstrip("/")
if folderpath.find(".SemanticModel") == -1:
    print(f"Failed to find the .SemanticModel folder, you provided as folder: {args.folder}")
    exit()
projectname = folderpath[folderpath.rfind("/")+1:folderpath.rfind(".")]

rels = load_relationships(args.folder)
diags = load_diagrams(args.folder)

tableinfo = dict()
for t in diags['All tables']:
    tableinfo[t] = load_table(args.folder, t)


# print(rels)
# exit()

# Rendering with dot -- needs to be installed in OS

graphattributes = dict()
graphattributes["overlap"] = "false"
graphattributes["ratio"] = "0.56"
graphattributes["comment"] = "Basic model for implicit measures"
graphattributes["layout"] = "neato"
graphattributes["splines"] = "curved"

nodeattributes = dict()
nodeattributes["shape"] = "box"

edgeattributes = dict()
edgeattributes["len"] = ("2" if args.showcardinality else "1.2")
edgeattributes["labeldistance"] = "1.8"
edgeattributes["labelangle"] = "20"

if args.generatebus:
    facts = set()
    for (starttable, startcol,endtable,endcol,isactive,crossfilter,tomany) in rels:
        facts.add(starttable)

    for (starttable, startcol,endtable,endcol,isactive,crossfilter,tomany) in rels:
        if (endtable in facts) and (not tomany):
            facts.remove(endtable)
    
    dims = set()
    for (starttable, startcol,endtable,endcol,isactive,crossfilter,tomany) in rels:
        if starttable in facts:
            dims.add(endtable)

    bus = [["" for x in dims] for y in facts]
    factlist = list(facts)
    dimlist = list(dims)
    for (starttable, startcol,endtable,endcol,isactive,crossfilter,tomany) in rels:
        if (starttable in facts) and (endtable in dims) and isactive:
            bus[factlist.index(starttable)][dimlist.index(endtable)] = ("m" if tomany else "1")

    busfile = open(f"{args.renderfolder}/{projectname}_dwhbus.csv","w")
    busfile.write(f"Facts,{",".join(dimlist)}\n")
    for f in factlist:
        busfile.write(f"{f},{",".join(bus[factlist.index(f)])}\n")
    busfile.close()


if args.onlymain:
    diaglist = ['All tables']
else:
    diaglist = [d for d in diags]

for diagram in diaglist:
    dot = graphviz.Digraph(f"Power BI diagram {diagram}", engine="neato",graph_attr=graphattributes,node_attr=nodeattributes, edge_attr=edgeattributes) 
    #consider nop2 for fixed locations (with pos)

    for (starttable, startcol,endtable,endcol,isactive,crossfilter,tomany) in rels:
        starttable = starttable.replace("'","")
        endtable = endtable.replace("'","")
        if (starttable in diags[diagram]) and (endtable in diags[diagram]):
            dir = ("both" if crossfilter else "forward")
            headlabel = taillabel = ""  
            if args.showcardinality:
                taillabel = ("*" if tomany else "1")
                headlabel = "*"
            if isactive:
                dot.edge(tail_name=endtable, head_name=starttable,dir=dir,headlabel=headlabel,taillabel=taillabel)
            elif args.inactive: # show inactive relationships with dashed edge
                dot.edge(tail_name=endtable, head_name=starttable,dir=dir, style="dashed",headlabel=headlabel,taillabel=taillabel)

    if args.skiprender:
        dot.save(f"{args.renderfolder}/{projectname}_{diagram}.gv")
    else:
        dot.render(format=args.format, view=False, outfile=f"{args.renderfolder}/{projectname}_{diagram}.{args.format}")

More details on why and how to use it on linkedin: https://www.linkedin.com/pulse/exporting-power-bi-diagrams-nico-jacobs-esdge/