Render Elements: Normals

This time let's do a brief anatomic study of a Normals output variable. Below is my original manuscript of an article first published in issue 188 of a 3D World magazine.
A typical Normals element rendered in screen space
The shaders and the AOVs
Although this might be obscured from the artist in many popular 3D applications, a shader (and a surface shader in particular) is actually a program run on each pixel*. It takes input variables for that pixel such as surface position, normal orientation, texture coordinates and outputs some variable value based on those input traits. This new pixel value...

Packing Lighting Data into RGB Channels

 
Most existing renderers process Red, Green and Blue channels independently. While this limits the representation of certain optical phenomena (especially those in the domain of physical rather than geometric optics), it provides some advantages as well. For one, this feature allows encoding lighting information from several sources into a single image separately, which we are going to look at in this article.
Advanced masking
For the first example let's consider rendering masks which we have discussed the last time. The image above introduces a bit more advanced scenario when an object is present in reflections and refractions as well, so...

Storing masks in RGB channels

Base image for the examples in this article
Finally returning to posting the original manuscripts of the articles I've written for 3D World magazine in 2014. This one was first published in issue 186 under the title "The Mighty Multimatte".
In an earlier piece we've been looking at raster images as data containers which may be used for storing various supplementary information as well as the pictures themselves. One of the most straightforward usage of these capabilities is rendering masks.
A lot can be done to an image after it has been rendered, in fact contemporary compositing packages even allow us to move...

CG|VFX reel 2015

//player.vimeo.com/video/128073234

CG|VFX reel 2015 from Denis Kozlov on Vimeo.
My reels tend to become shorter and shorter. Here goes the new one – a generalist's reel again, so I have to take the blame for most of non live action pixels – both CG and compositing. With only a couple of exceptions, the work has been done in Houdini and Fusion predominantly. Below follows a breakdown describing my role and approach for each shot.
 
Direction and most visual elements for this version of the shot. The main supercell plate created and rendered in Houdini with a mixture of volumetric modeling techniques and...

On Wings, Tails and Procedural Modeling

Project Aero: Procedural Aircraft Design Toolkit for SideFX Houdini
I find Houdini a very powerful tool for 3D modeling. In fact, this aspect was largely motivational for me to choose it as a primary 3D application. And talking procedural modeling I mean not just fractal mountains, instanced cities and Voronoi-fractured debris (which all can be made look quite fascinating actually), but efficient creation of 3D assets in general. Any assets.
Thus lately I have taken some of the not-so-free time (a bit over 3 months, to be more accurate) to develop (or rather prototype) a toolkit for procedural aircraft creation, which I...

Evaluating a Particle System: checklist

Below is my original manuscript of what was first published as a 2-piece article in issues 183 and 184 of a 3D World magazine. Worse English and a bit more pictures are included. Plus a good deal of techniques and approaches squeezed between the lines.
Part 1
Most of the 3D and compositing packages offer some sort of a particle systems toolset. They usually come with a nice set of examples and demos showing all the stunning things you can do within the product. However, the way to really judge its capabilities is often not by the things the software can do, but rather by the things...

Project Tundra

01. Tundra
Since I find it very cool to call everything a project, here goes “Project Tundra” with some anagrams. Pretty much all visual elements (except for a couple of bump textures) are completely synthetic and generated procedurally with Houdini and Fusion. So almost no reality was sampled during the production of the series. Some clouds from these setups were used. 
The originals are about 6K in resolution. I'm a bit split between the desire to write that prints will follow shortly, and the desire not to lie. Let's say they will follow for sure if you're patient enough to follow the slowly revolving pace of...

Bit Depth - color precision in raster images

Last time we have been talking about encoding color information in pixels with numbers from a zero-to-one range, where 0 stands for black, 1 for white and numbers in between represent corresponding shades of gray. (RGB model uses 3 numbers like that for storing the brightness of each Red, Green and Blue components and representing a wide range of colors through mixing them). This time let's address the precision of such a representation, which is defined by a number of bits dedicated in a particular file format to describing that 0-1 range, or a bit-depth of a raster image.
Bits...

Pixel Is Not a Color Square

Continuing the announced series of my original manuscripts for 3D World magazine.
  Thinking of images as data containers.
Although those raster image files filling our computers and lives are most commonly used to represent pictures (surprisingly), I find it useful for a CG artist to have yet another perspective – a geekier one. And from that perspective a raster image is essentially a set of data organized into a particular structure, to be more specific — a table filled with numbers (a matrix, mathematically speaking).
The number in each table cell can be used to represent a color, and this is how...

Procedural Clouds

I've been playing around with generating procedural clouds lately, and this time before turning to the heavy artillery of full scale 3D volumetrics, spent some time with good old fractal noises in the good old Fusion.
So row by row, top to bottom:
The base fractus cloudform generator assembled from several noise patterns: from the coarsest one defining the overall random shape to the smallest for the edge work. It is used as a building block in the setups below. Main trick here was not to rely on a single noise pattern, but rather to look for a way to...