CG:Skeelogy

Now On Twitter

Skeel — Mon, 04 May 2009 00:09:49 +0000

As part of the Web 2.0 effort, I am now on Twitter! Follow me at http://twitter.com/skeelogy. I’ll try to give updates on the stuff that I am working on and their progress. Stay tuned…

CG:Skeelogy v1.1: The Web 2.0 Version

Skeel — Tue, 21 Apr 2009 00:28:58 +0000

CG:Skeelogy is now Web 2.0 enabled. With WordPress as its backbone, you can now browse through the site more easily using tags and related-post links. You are now also able to leave comments in the posts. I’ve also sorted out the categories of the posts in my website so that it is now more organized and has room for more things to come.

I know it’s a little late to be in the Web 2.0 mode, but hey, better late than never. Hope you like the new browsing experience.

Best Physics Knowledge Base Entry In Intel Havok Physics Contest!

Skeel — Sun, 22 Mar 2009 20:43:19 +0000

My soft body physics tutorial just won the first prize in the Best Physics Knowledge Base Entry category of the Intel Havok Physics Contest! The results were announced during Games Developers Conference 2009. The prize is a Velocity Micro® Edge™ Z55 Gaming PC worth US$2,000.

This is the third prize that I have received with this soft body physics tutorial and I do hope that it has helped game developers out there who are interested in this area.

Triple w00t!

Community Voting Prize In Intel Havok Physics Contest

Skeel — Sat, 07 Feb 2009 21:19:25 +0000

My soft body physics tutorial just won the Community Voting Prize for the Best Physics Knowledge Base Entry category of the Intel Havok Physics Contest. The prize is a US$100 VISA gift card, and is given to the entry with the highest rating at the end of each month. I won the prize for the month of January 2009.

This is the second prize that I have won so far with my soft body physics tutorial, and I am eagerly waiting for the main results of the Best Physics Knowledge Base Entry category. Wish me luck!

Working at Double Negative in London

Skeel — Mon, 12 Jan 2009 01:16:06 +0000

After much await, I am finally starting my job here at Double Negative in London. I’ll get to work with experienced veterans on blockbuster movies to be screened, and I am seriously quite excited about it. It’ll definitely be a good learning experience. Look out for my name in the credits of films made by Double Negative in the near future!

Double Negative, London

First Prize In The Ziggyware Fall 2008 XNA Article Contest!

Skeel — Thu, 25 Dec 2008 18:04:32 +0000

My soft body physics tutorial just won the first prize in the Ziggyware Fall 2008 XNA Article Contest! I am extremely glad that my effort for writing the tutorial has not been wasted and that many XNA’ers have found the tutorial to be beneficial (according to the comments in the article site).

These are the prizes and goodies that I have won:

XBox 360 Elite with an additional wireless controller
One year Microsoft XNA Creators Club premium membership
Milkshape 3D license
1600 MS points

Just like to say thanks to Ziggy for organizing this competition over and over again. Many great articles have been written due to these competitions. Kudos to all the other authors too. Many of the articles in the competition this time round are awesome and definitely beneficial to the XNA community. Last but not least, let’s not forget our kind sponsors chUmbaLum sOft for the MilkShape 3D license, Gamedevkicks.com for the 1600 MS points and other kind donors for the rest of the prizes!

w00t!

SIGGRAPH Asia 2008

Skeel — Sat, 13 Dec 2008 01:14:01 +0000

Recently I attended the first ever SIGGRAPH Asia conference held in Singapore (it’s kind of hard not to attend such a major event when I live here in Singapore!). While the scale of the event is not as huge as the one I attended in Los Angeles a few months back, the spirit of showcasing new technologies and bringing them to the industry is definitely there.

SIGGRAPH Asia 2008 in Singapore

I went for a few talks that I was interested in, in particular a talk by the Thalmanns which covered anatomical modeling research, and a couple of behind-the-scenes talk by Double Negative. The talk on Houdini was pretty awesome too and it really showed the capabilities of this powerful software. I had a good chat with different companies, met up with lots of friends, and ended the event with some animation shorts from the animation festival.

Attending two SIGGRAPH conferences in a year, awesome!

Introduction to Soft Body Physics in XNA

Skeel — Sat, 29 Nov 2008 23:14:31 +0000

Recently I have written an introductory tutorial on how to program your own soft body simulations in real-time environments. Here are some of the things that you will be able to create by the end of the tutorial:

Cloth Simulation

Slinky Simulation

Chain Simulation

The web version of the tutorial can be found at the Ziggyware website, while the PDF version can be found at the Intel Havok Physics Contest website.

NOTE: It assumes that you are an absolute beginner in physics simulation programming, but it does assume that you know about object-oriented programming. The tutorial uses XNA 3.0, which is the framework used for creating games on the PC, Xbox 360 and the Zune (Microsoft’s MP3 player). The language used is C#.

Hope you like the article!

Pseudo Chain Simulation

Skeel — Sat, 29 Nov 2008 11:19:00 +0000

A fake chain simulation written using Microsoft XNA 3.0. It is meant to mimic a rigid body simulation by using a cheaper alternative: a soft body simulator. Length constraints are used to maintain the distances between the chain segments, which makes the whole chain look like it is undergoing some kind of collision handling.

Video showing the fake chain simulation in action

Pseudo Slinky Simulation

Skeel — Sat, 29 Nov 2008 11:12:00 +0000

A fake slinky simulation written using Microsoft XNA 3.0 where the user can use the mouse to push it around. This is done simply by applying a simple alpha texture map onto a cylindrical soft body.

Video showing a fake slinky simulation in action

Real-Time Cloth Simulation

Skeel — Sat, 29 Nov 2008 09:26:00 +0000

A cloth simulation written using Microsoft XNA 3.0. This uses a series of springs (structural, shear and bend springs) and constraints. The two top corners of the cloth is pinned using a point constraint and can be controlled by the user.

Video showing a simple cloth simulation in action

The main building blocks of a good cloth simulation are the three kinds of springs:

Structural springs: These are the main springs in the cloth that are placed along each quad edge
Shear springs: These are springs which helps maintain the diagonal shape of the cloth and are placed along the two diagonals of a quad
Bend springs: These are springs which help to control the bending of the cloth and are placed like the structural springs but connects vertices that are two vertices apart

To illustrate how the different kinds of springs are important, I have created some videos to show how the cloth will look like without some of them.

The video below shows how a cloth simulation will look like without using shear and bend springs (i.e. using only structural springs). The cloth tends to lose its shape very easily, as can be seen when the two corners are brought close together.

Cloth simulation without shear and bend springs (i.e. using only structural springs)

The video below shows how a cloth simulation will look like without using bend springs (i.e. using only structural and shear springs). The cloth looks decent when fully stretched out, but starts to show signs of poor deformation when it bends. It tends to fold too easily and sometimes even stays folded (e.g. at the end of the video).

Cloth simulation without using bend springs (i.e. using only structural and shear springs)

Constraints are another important building block of a good cloth simulation. Length constraints help to maintain the distances between the vertices and can be thought of as a spring of infinite stiffness. The video below shows how a cloth simulation will look like without using length constraints. The cloth tends to be very elastic and quite unstable as the different springs fight against one another.

Cloth simulation without using length constraints

Stable Fluid Running On Zune

Skeel — Sun, 26 Oct 2008 16:56:00 +0000

Recently implemented Jos Stam’s stable fluid. Programmed it in Microsoft XNA 3.0 which basically means it can run on the PC, Xbox360 and the Zune MP3 player. This video shows the simulation running in real-time on the Zune itself. The touchpad on the Zune is pretty useful as an input device!

Pressing the Play button (top button in the video) toggles between Add-Fluid mode and Push-Fluid mode.

Video showing real-time interaction with the fluid on the Zune using the touchpad

Coke Cans

Skeel — Tue, 16 Sep 2008 06:38:00 +0000

Created some coke cans and rendered them using a HDR image that I have created. Some post-processing effects such as depth of field was done using Photoshop.

Coke cans galore!

SIGGRAPH 2008

Skeel — Fri, 15 Aug 2008 19:54:18 +0000

I attended SIGGRAPH 2008 recently in Los Angeles, California. I was there primarily to attend the masterclasses, which covered a variety of areas such as rigging, lighting, animation, and even scripting. I also managed to find some spare time to attend some sessions in the main SIGGRAPH conference and exhibition area. The showcase of new technologies were simply amazing and I think that’s what SIGGRAPH is about: bringing new technologies to the industry, year after year. I enjoyed the industry talk sessions too since they showed a lot of behind-the-scenes footages, and sometimes even sharing some in-house tips and tricks that they use in production. After the trip, I gathered some good ideas for implementations that I can try out in the near future. I also got to see quite a number of graphics researchers (e.g. Jos Stam!) whose names I have seen in great research papers, and spent a couple of days touring Hollywood as well. Fruitful trip indeed!

SIGGRAPH 2008 at Los Angeles Convention Center

Rigging Demo Reel

Skeel — Wed, 18 Jun 2008 08:44:00 +0000

Introduction

Finally finished up my rigging demo reel! It showcases the character rigs and deformation techniques done over the past few years. There are also some components that shows the technical implementations of tools and existing techniques (e.g. IK) to demonstrate my knowledge in these area.

My rigging reel that shows rigs, simulations and tools created

Skills and Experience

Skills and experience in rigging and deformation

Able to rig different types of characters, with appropriate controllers/UI for animators
Knowledge of anatomy and model topology
Able to use existing tools, and able to implement existing/new technologies as well e.g. IK, linear blend skinning, soft body, subdivision etc.
Skills: Linear algebra, computer graphics pipeline, Maya API, Maya Python, MEL

Misc

The designer inside me couldn’t resist packaging the demo reel that I was giving out to recruiters and potential employers. These are mini-cds in thin, colored jewel cases. My namecard fits nicely to the left of the cover. Overall a compact and sleek demo reel to pass around.

Packaging design of my demo reel

Muskeelar in CommunicAsia 2008

Skeel — Tue, 17 Jun 2008 13:34:00 +0000

Muskeelar was showcased in CommunicAsia 2008 (Asia’s premier information and communications technology event) from 17 to 20 June 2008 at the Singapore Expo. It was featured as one of the real-time technologies for games.

Booth in CommunicAsia 2008 showcasing Muskeelar as one of the technologies

Tweakable Fish

Skeel — Sun, 01 Jun 2008 14:18:00 +0000

Created a fish that allows the user to tweak the proportions and shapes of different body parts. It comes with a simple face rig as well to give the tweaked fish some personality. An expressiveness attribute is provided to the user to determine how expressive the fish will be when randomized.

Creating different fishes using the tweakable fish GUI

First Class Honours in Computer Science!

Skeel — Sat, 31 May 2008 08:31:00 +0000

I don’t really like to tell people about my grades actually, but since it affects my job seeking chances, I think I shall declare it: I have finally obtained my First Class Honours Degree in Computer Science!

I was selected to attend a special graduation ceremony for graduates with achievements. I was particularly recognized for the real-time muscle system that I have developed. It was an honour to have received my degree scroll from the President of Singapore S. R. Nathan who was the Guest-of-Honour for the ceremony. Other than my degree scroll, I was also presented with a prize for having one of the top two UROP projects done in 2007.

Receiving my degree scroll from President S. R. Nathan in a special ceremony for graduates with achievements

It has been four extremely long years in university and countless hours of blood and sweat (and countable hours of sleep!). I hope all these hard work will land me in some place good and not waste my efforts that I have put in to prepare myself for the animation/games industry.

Mocap-Ready Facial Rig

Skeel — Tue, 20 May 2008 13:55:00 +0000

Created a facial rig for use with motion capture data. Scripts have been written to link up the GUI to the mocap data. Different parts of the face can be specified to be hand-animated only and not follow the mocap data after binding. The GUI also allows tweaking of the expression after the facial mocap animation.

The rig can also be used independently without motion capture data, as demonstrated in the video below.

Creating different expressions using the intuitive GUI

Note: Head model obtained from MakeHuman

Game Physics Demo Reel

Skeel — Thu, 01 May 2008 13:47:00 +0000

Introduction

Finally got my first demo reel up! Kinda ironic that my first demo reel is on game physics when I’ve been preparing myself for character rigging for the past few years. Well, I’ve been programming simulations here and there for the past couple of years and I have finally created something decent to show.

This demo reel showcases the implementations done for character physics, fluid physics and soft body physics. There is also a section on collision handling between different types of objects. Most of them are implemented using Microsoft XNA 2.0, with some done using OGRE.

My game physics demo reel

Skills and Experience

Skills and experience in rigging and deformation

Understand and able to quickly implement many real-time algorithms for physics simulation, fluids and deformable bodies
Published a paper on real-time muscle dynamics that enables real-time muscle jiggles for game characters
Developed a physics library for XNA that allows quick creation of cloth, balloon and other soft bodies
Tech demos on Pressurized Soft Body and Smoothed Particle Hydrodynamics are now permanent showcases in Microsoft Innovation Centre Singapore
Used physics for soft bodies as the main game concept for a 3D casual game (Cloud Guardian)
Skills: Numerical integration, physics dynamics theory and equations, XNA, OGRE, C#, C++, C

Misc

Packaging design of my demo reel