Wednesday, August 19, 2009
Tuesday, August 11, 2009
Computer Graphics Pipeline
Before we move into an in-depth examination of CG production pipelines, let 's clarify our definition of a pipeline. In parts 1 to 4 of this series, we deconstructed the pipeline and looked at what it is not and the characteristics that define a CG pipeline.
In preparing this series, drawn mostly from my own experience, I made a survey of available documents on the internet and found very few discussions about CG pipelines, other than a plethora of want ads for supervisors capable of defining, constructing and maintaining CG production pipelines. I did come across a masters thesis by Dane Edward Bettis, written in 2005, that attempted to define the CG production pipeline, describe the need for CG production pipelines, and provided examples of operating pipelines and a brief methodology for designing a CG production pipeline. His paper, "Digital production pipelines: examining structures and methods in the computer effects industry", published online through Texas A&M University, looks at CG production pipelines from the point of view of companies making fully animated 3d films. It is an interesting academic look at our industry.
Monday, August 10, 2009
In part three, #0020 The Technology is Not the Pipeline, we differentiate technology pipelines as found within software and hardware tools from production pipelines. We also introduced the three dimensions of pipelines: personnel, tools and procedure. We continue now to define the scope and nature of CG pipelines by dealing with a common area of confusion, the difference between a workflow and a pipeline. While this was dealt with to some degree in bog #0020 using the analogy of a fry cook and a baker, I wish to refine the concept for us.
Sunday, August 2, 2009
If you have not found it yet, noted VFX Supervisor Scott Squires has a blog on VFX called Effects Corner, http://www.effectscorner.blogspot.com/.
Topics in the blog, which has been active the last few months even while Scott is working on the forthcoming VES Handbook, range through a variety of VFX issues, including some managerial and many technical and artistic.If particular relevance to readers looking to learn about CG and VFX Supervision is his post on VFX management, which gives a quick overview of some of the important issues we are discussing. See Effects Corner: VFX management
By Isa A. Alsup at 1:55 AM
Saturday, August 1, 2009
Image via Wikipedia
Let's look at the difference and while we're at it, look at the common attributes found in the three classes of pipelines: production, material and approval.
If one were to decompose the CG production process into a more generalized graphic design process, one could see that a simplified production pipeline in graphic arts is comprised of:
- acquisition of assets
- impression aka reproduction aka rendering
The answer is there are technology pipelines within the realm of computer science at both the application and the hardware level, but these are not CG pipelines as such. Recall that in article #0018, Understanding Pipelines we looked at how Silicon Graphics introduced the hardware graphics engine, or graphics pipeline, in the early 1980's. The use of data piping within software and hardware is an essential part of today's CG technology. It is the most likely origin of the word "pipeline" to describe the production processes used in computer graphics today.
When frying an egg one gathers the egg, the pan and the oil in one spot, fires up the heat, oils the pan, breaks the egg in the pan and let's it warm and solidify, then flips (or not) the egg once and calls it done. This is a process, not a pipeline. The reason is there is no step by step evolution of the egg being fried.
One could argue that frying an egg can be broken down into a series of tasks. The distinction is that dividing these tasks into separate processes is not meaningful when it comes to frying an egg but can be beneficial when baking a cake. So a pipeline is comprised of a sequence of processes that can flow in a linear or parallel nature relative to one another.
As this example illustrates, the processes of computer graphics together comprise a pipeline. Just as some computer software procedures can be linked together to form a pipeline for processing data, so the procedures in computer graphics are tied together to make a pipeline. However, they are not a pipeline until they are tied together.
For example, the surface modeling process requires personnel with specific skills and abilities using tools with specific capabilities while observing specific work procedures governing not only the process but also the movement of the assets in and out of the modeling phase.
Less obvious is that the dimension of procedure lends itself to partial automation through the use of technology. A pipeline can exist with little or no automation of procedures for moving data through the system, but it will suffer from the vagaries of human error and negligence. As Mr. Bettis points out, this is an area that should be automated. He believes it so strongly that in his thesis he makes no allowance for non-automated implementation of policies and procedures related to the movement of the product through the pipeline. The degree a company can and should invest in this automation depends on factors we will discuss in a future article.
While the pipeline IS NOT the technology, as a technological art, the computer graphics pipeline depends a great deal on technology. We will explore these ideas further as we discuss in detail the three classes of pipelines: the production pipeline, the material pipeline, and the approval pipeline.
Bettis, Dane Edward "Digital production pipelines: examining structures and methods in the computer effects industry", Texas A&M University, http://txspace.tamu.edu/handle/1969.1/2406?show=full, 2005; A useful examination of the digital pipeline with specific examples of pipeline structures.
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