Blender 3D: tutorials, articles, tips, notes
The official Blender documentation provides a method to get the “Specular” value for the PBR-material reflections if the “IOR” value is known. To get the “Specular” value from the “IOR” value, we can use the following equation:
It is not difficult to create it with nodes:
There is a convenient opportunity in the Cycles render engine to render an object with shadows on a transparent background using material with the “shadow catcher” option. There is no such material in EEVEE render engine, however, in EEVEE we can make our own “shadow catcher” based only on nodes.
Completed “EEVEE Shadow Catcher” material you can get from the BIS library.
In Blender Cycles using common lamps we can illuminate objects with any texture, not just a single color.
Add an object, for example – sphere, to the scene:
shift+a – Mesh – UVSphere
and set a simple diffuse shader to it.
Except for the “Gradient Texture” node, we can obtain a gradient factor by using some simple equations. Look for the mathematics with a spherical gradient sample.
Can be created based on a downward-facing cone equation.
The simplest way to pixelate texture, procedural or not – get the color from the single pixel and fill the region with required width and height (resolution) with this color.
Here is the gradient texture with red – green – blue colors:
To pixelate it with the first step of resolution we can make some vectors manipulations.
Creating separate elements of procedural textures in Blender is quite simply – find the desired formula, rebuilt it using mathematical nodes, and as a result, get the desired shape. However, textures created this way have one feature – no tiling. Tiling – a cyclic texture duplication, most time is considered harmful, and professional 3D artists try to avoid texture tiling. But sometimes tiling is necessary, for example, when creating patterns or ornaments.
The procedural texture element is always created in a single instance. This is because all the mathematics that forms the actual procedural image is based on the initial data – coordinates that start from 0, spread out to infinity and not repeat. However, the same mathematics helps us to solve this problem.
All procedural textures in Blender are based on math. Even such irregular structures as “Voronoi” and “Noise” are actually generated according to the mathematical formulas. An exact mathematical algorithm is sewed up into each base material node to obtain the desired image as a result.
We can not specify such algorithms in Blender in the usual mathematical format. However, among other nodes, Blender provides us the “Math” nodes – the wrap over simple mathematical operations. Using these nodes we can build complex mathematical algorithms yourself, generating interesting textures.
In order to achieve the desired texture mapping on the object surface, we need a convenient tool for manipulating the texture coordinates. Especially for procedural textures mapped to the object without using UV-s.
The “Mapping” node combines tools for texture moving, rotating and scaling is suitable for most of the texturing tasks. But sometimes its power is not enough. Its major drawback is that it allows setting adjustment values only in certain fields within the node body. These fields have no inputs and cannot be connected to the other nodes.
However, we can implement the required functionality devoid of the “Mapping” node lack with the help of some other nodes. Let’s consider how to build a node tree to rotate the texture around the Z-axis of the object by a random value.
