May 292016

I was quite surprised how much the choice of anti-aliaser affects a render. Here I’ve rendered a scene with all the 3DS anti-aliasers, to compare how they fare. The scene is a ring (which you might wear on a finger), using Neil Blevins beautiful gold material. The subject is 5 intersecting toruses, scanline renderer, with an HDR skylight based on Desk_Sm_Blurry.hdr. I discovered that all the anti-aliasers are very susceptible to the radiosity quality, there is a huge difference in the artifacts between the 85% default and 99% radiosity that I used.

Area, nice at first glance, but a bit cartoony


Blend, not suitable for this kind of texture


Blackman, a little blurry but quite realistic


Catmull-Rom. Convincing, but a little too much


Cook Variable. Very crisp in the highlights, a bit blurred elsewhere


Cubic. Poor unlit areas


Mitchell-Natravali. Crisp compromise, my favourite


Quadratic. A little surrealist and over-smoothed


Sharp Quadratic. A little better than the basic quadratic, but still too smoothed


May 102011

Pavel in St. Petersburg asked me if it would be possible to produce bubble diagrams like this in Excel:

UK Public Spending

Excel has had bubble diagrams sine 2003 but they are just an X-Y plot with variable-sized nodes. What Pavel was after is an automatic layout, with lines joining the nodes, along these lines:

Bubble diagram with Graphviz

Not perfect, but you get the idea, and it’s produced automatically. To do this, you’ll need Excel, Visio, Graphvizio and this zip file which contains the sample XLS, GV, VSD and JPG files.

  • Open the XLS. Column A is the node’s title, B is the title and the amount separated by a newline. Columns C, D and E specify the node’s parent, colour and amount. Column F computes the diameter of the node, in inches, from the amount:

Column G just creates Graphviz DOT statements from the values. G1 and G2 are the prelude. Copying column G into a text file called bubble1.gv, we get:

graph  RootGraph {
node [fontname=Arial, fontsize=12, style=filled];

"Total\n620" [width="3.1", height="3.1", color="gray", fillcolor="gray", shape=circle];

"Children, schools, family\n63"--"Total\n620" [color="pink"]; "Children, schools, family\n63" [width="0.315", height="0.315", color="pink", fillcolor="pink", shape=circle];

"Schools\n42"--"Children, schools, family\n63" [color="pink"]; "Schools\n42" [width="0.21", height="0.21", color="pink", fillcolor="pink", shape=circle];



  • Fire up Visio. Graph>Diagram->Import Graphviz
  • To get the circular layout, Graph->Settings->Diagram->Concentric
  • Graph->Layout
  • A little tweaking of the font sizes and line thickness and you’re on your way


May 112010

In the process of analysing a client’s existing database, I used Visio’s reverse-engineering tool. It works well, but the resulting diagram was an incomprehensible bowl of spaghetti. Visio does have a “Layout shapes” command, which appears to work by moving shapes with repulsive forces and the result is, not surprisingly, repulsive.

What I wanted was a tool which would unravel the spaghetti, so that I could get a grasp of the relationships, edit and revise them and layout again in an iterative process.
Searching for a solution, I found three layout programs, none of which have a Visio interface:

  1. Microsoft Automatic Graph Layout (MSAGL), formerly known as GLEE The first version, GLEE, is free whereas MSAGL costs between 99 USD and 279 USD depending on where you buy it.
  2. Tom Sawyer Layout is also a graph layout library, the price isn’t disclosed on their website.
  3. Graphviz from AT&T research labs, reputed to have the most sophisticated layout algorithms, is free.

Given that the best quality was to be found in the free library, I made the obvious choice.
It took me over a year and some 11’000 lines of VB to get Visio and Graphviz to co-exist; marrying a Unix-style command-line program with a WYSIWYG interface, both with quirks to numerous to mention, was far more challenging than I initially thought.
The result, unimaginatively called GraphVizio, is available here, I hope you’ll find it useful.

25 May 2011 Version 1.1.5 released. Improvements:

Full support for 64-bit Windows and Visio

No longer makes a Visio document ‘dirty’ when opening

Full support for UTF8. This DOT file:

graph  RootGraph {
  node [width="7.08661417322834", height="0.787401574803148", color="#000000", fillcolor="#FFFFFF", fontname=Calibri, fontsize=24, style=filled, shape=box];
  edge [color="#000000", fillcolor="#FFFFFF"];

  "English: Hello, my name is Maurice\n(and blame Google if the translations are bad)" [pos="283.704566929134,620.932913385827", label="English: Hello, my name is Maurice\n(and blame Google if the translations are bad)"];
  "Russian: Здравствуйте, меня зовут Морис" [pos="283.704566929134,526.932913385827", label="Russian: Здравствуйте, меня зовут Морис"];
  "مرحبا، اسمي موريس : Arabic" [pos="283.704566929134,432.932913385827", label="مرحبا، اسمي موريس : Arabic"];
  "Chinese: 你好,我叫莫里斯" [pos="283.704566929134,338.932913385827", label="Chinese: 你好,我叫莫里斯"];
  "שלום, שמי הוא מוריס : Hebrew" [pos="283.704566929134,244.932913385827", label="שלום, שמי הוא מוריס : Hebrew"];
  "Japanese: こんにちは、私の名前はモーリスです" [pos="283.704566929134,150.932913385826", label="Japanese: こんにちは、私の名前はモーリスです"];
  "Thai: สวัสดีชื่อของฉันคือ Maurice" [pos="283.704566929134,56.9329133858268", label="Thai: สวัสดีชื่อของฉันคือ Maurice"];

  "English: Hello, my name is Maurice\n(and blame Google if the translations are bad)"--"Russian: Здравствуйте, меня зовут Морис";
  "Russian: Здравствуйте, меня зовут Морис"--"مرحبا، اسمي موريس : Arabic";
  "مرحبا، اسمي موريس : Arabic"--"Chinese: 你好,我叫莫里斯";
  "Chinese: 你好,我叫莫里斯"--"שלום, שמי הוא מוריס : Hebrew";
  "שלום, שמי הוא מוריס : Hebrew"--"Japanese: こんにちは、私の名前はモーリスです";
  "Japanese: こんにちは、私の名前はモーリスです"--"Thai: สวัสดีชื่อของฉันคือ Maurice";

produces this Visio diagram:

Graphvizio UTF8