A Technical Director's personal website

I looked over a personal website of a fx td named Hosuk today. He has posted many pictures and some videos of some of his projects. He has examples that were created with Houdini and python as well as other software.

Scott Squires Bio

Some biographical information about the creator of the iphone Squiggles paint app.

Another post at real-time rendering

More interesting links posted at the real-time rendering blog.

The OpenGL 3.2 and GLSL 1.5 tutorial programs he mentions sound like they could be useful. I started to investigate the shader language part of OpenGL recently but didn't get very far. Using a gpu to speed up the drawing of computer graphics sounds like it could be useful thing to know. It seems the new features of OpenGL are encouraging that direction. At the least, I'm planning on reading the code for a phong shaded sphere at the tutorial site to compare with some the code of a toy ray tracer in Python.

Image Convolution

A tutorial on image convolution is available on a page at Arizona State University.

introduction to ray tracing

Eric Haines descibes on his blog a book called Another Introduction to Ray Tracing. It is a collection of articles about different aspects of ray tracing. The different articles describe a variety of topics and have reference links like wikipedia.

overview of ray tracing

An overview of ray tracing is available at a siggraph web site. I'm looking into it as a way to learn some 3-d graphics math by applying it in a simple program. Unfortunately I'm expecting the images produced by such a simple program not to be very interesting.

The pictures at this site about terrain generation with ray marching do look interesting though, and the author claims that the code is simple as well. Also, the explanation of the method involves techniques similar to ray tracing.

First iPhone Application tutorial

With the wifi version of the iPad now available, I decided to try again to make my first iPhone app. Also, fortunately I had some extra time off from work with this being Easter weekend. So, I went over this tutorial for making a Hello World type of iPhone application. It has a bunch of stuff with gui building that seems to make it a worthwhile exercise. That is, it should be more useful than a tutorial that just displays some words on the screen. There are text boxes that take in strings, and a button that responds to tapping by displaying a message in a label control. In other words, it does some basic input and output together with event handling.

Jansen walking machine animation

An animation of a Jansen walking machine is on sidefx software's website. The artist used Houdini and its support of expressions to create it.

Rendering Tips

This blog has a bunch of tips on how to avoid bad renders: Stopping Bad Renders...By Per Andres.

It is a Cinema 4D specific blog, but it looks like some of the tips could apply to Houdini as well.

Curves

This is to record a blog entry with a visual dictionary of special plane curves.

OpenCL blog post

A blog describes possible Blender improvements using OpenCL. It also has some tips on installing it in Ubuntu 9.10, 32 bits, Ati 4770.

Performance Comparison of Houdini and SoftImage

ICE vs VOPs a performance comparison

The author of this blog entry describes how SoftImage's new feature called ICE compares with Houdini's VOPs. Both applications now have a node network, and the author shows some examples of them with some screen shots of tests he runs. These five tests are empirical in the sense that they are experiments that measure the time it takes to complete certain tasks. By presenting this timing data, the writer strikes a neutral tone while still encouraging the reader to make a value judgement about SoftImage's performance wins. While the differences in time he presents are in the range of seconds, it seems reasonable that such a performance improvement could build up to hours for renders with a large number of frames and calulcations. I haven't worked with Houdini or SoftImage for several months now, but this comparison still looked interesting.

High Speed Robotic Hand

http://www.youtube.com/watch?v=bfdHY26E2jc

from Ishikawa Komuro Lab, University of Tokyo:

Concept

Interactions in the real world (not only physical but also social and psychological interactions) are inherently parallel phenomena. By constructing models and engineering systems that take into account such parallelism, one can expect a better understanding of the real world as well as enhanced performance of systems when dealing with practical applications. These fundamental considerations lead us to concentrate on parallel processing for sensory information. Four main related topics are currently being explored in Ishikawa-Komuro Laboratory:

1. Sensor Fusion theory and implementation in engineering systems;
2. Dynamic Image Control Dynamic control of image based on high-speed visual information processing;
3. Massively parallel image processing through a Vision Chip, which is capable of realizing high-speed real-time vision tasks on the basis of VLSI technology, and
4. Meta Perception concerns ways of capturing, manipulating and presenting information which is normally inaccessible to humans and machines.
5. (Past research on Optics in Computing: architectures that combine the advantages of optics and electronics to realize enormous computing throughput)

Another Demo of Importing Data into Houdini

There is another demo of importing data into Houdini shown on the Houdini Community Blog. It demonstrates an program using OpenCV to send out data that Houdini then uses to change perspective of a camera. I don't have time to pursue this right now, but perhaps some time later it could be useful for something else.

Pessimistic article about OpenCL

Compilers and More: OpenCL Promises and Potential

from the article:
So let's accept and even celebrate OpenCL for what it is, and not try to make it what it can't be. There's danger is raising expectations too high, or claiming too much (a la Bernie Madoff); OpenCL can be influential and succeed without replacing other parallel languages. To correct Steve Job's quote: "While OpenCL is very similar in many respects to NVIDIA's CUDA, it adds features to take advantage of other targets; and though it's quite complex, it has the potential to deliver very high performance, and is much easier than trying to map your computation into OpenGL or graphics primitives." Hype I can agree with; but then, I'm not the Apple CEO.

opencl

I'm starting to learn some of what needs to be done to use OpenCL by watching some podcasts here. OpenCL stands for Open Computing Language. It is a software development framework to aid doing general purpose graphics processor computing. So when applied in a program, some work is moved away from the cpu over to the graphics board across a bus. Even though moving data back and forth between the cpu and gpu is slow relative to the number of instructions a cpu could have executed on data had it not been moved, the speed of newer graphics boards with certain operations, like doing many simultaneous floating point calculations, can make the operation result in a net improvement in performance.

The Khronos group defines the OpenCL specifications. They also handle OpenGL. According to web articles both Nvidia and ATI now support OpenCL in many of their graphics boards. However I've seen some people mention problems trying to build and then get samples of the library to work with their graphics cards.

Surface Shader update on Vimeo

PQ Houdini posted an update to the surface shader of a brick. The update corrects some flaws with the previous shader.

PQ Houdini Tutorial on Vimeo

Some additional video tutorials by PQ Houdini for the 3d application Houdini are available on Vimeo. The brick shader he built in VOPs looked interesting. Many of the operators in the video were new to me, such as filter and color mixer. I haven't made much progress with Houdini since the last post, but perhaps this site will help.

Houdini and 3DConnexion Devices

A blog entry at geneome.com describes an attempt at using Python to enable 3DConnexion SpaceNavigator support in the Houdini 3D app.

He mentions a complication involving the lack of _ctypes.pyd in the Houdini Python distribution. Houdini 10 includes Python 2.5 and some commonly used modules with its 3d app, but apparently it was not enough for this project. I don't completely understand the post, but it sounds like this prevented the Python comtypes module from working, and that prevented Python from polling of the device driver using COM (Component Object Model). A workaround involved compiling the needed module himself with the Python compileall module in Houdini and then putting the binary code in the lib directory of Houdini. I'd never heard of the compileall module before reading the post and will take quick look at it later.

Another complication involved Houdini freezing during display of data from the 3dConnexion device into a window.

He posted a video of a demo to vimeo.

The post also references an odforce post with some one else's Python code that does the same thing and was apparently was developed simulaneously.

From the post:
The SpaceNavigator seems ideally suited to be able to control not just a camera but any object in 3 dimensions, provided that the application can see and understand the device.

more cg roundup podcasts

CG round up podcasts 6 & 7 are now available at www.cgroundup.com.

I still haven't gotten to listening to them yet.

A comment on one of these new podcasts mentions a blog post that does a comparison of ICE vs. VOPs. Looks interesting.