Статьи: Эксклюзив

Making-of in Blender: The Brushes

Hi! My name's Gleb Alexandrov (Spelle) and it's time for another Making-of. Today we're going to talk about “The Brushes” - still life render which pretends to be a photo. In case of our brushes, the idea came from aesthetic experience. There is a jar with brushes on my table. It's so routine and usual that it fails to catch attention. But once I noticed something unusual. At this time of the year, about 11 o'clock in the morning sun is looking into my window. One day, brushes were lit so brightly and looked so joyful that at the instant rather dirty jar became lively. Worth rendering.

MODELING

In terms of modeling the scene is quite simple and pleasant, with exception of the hair (will talk about it separately). Wooden handles of the brushes are basically the sameThough, made ​​a few unique ferrules.

The jar is a curve with a screw modifier and also solidify modifier.

Ring was pulled out of the cylinder and was flattened at the bottom using proportional editing.
TEXTURES AND MATERIALS
During the first tests of lighting, camera angle and object position simple materials were used. They consisted of just 1 seamless texture and were quite primitive in terms of shader complexity. Just mix between diffuse and glossy. But as the time was passing, desire was growing to make every brush unique.
To understand what happened, it is enough to recall the notorious advice on how to draw an owl in two steps:

Draw two circles, draw the rest of the owl.

On the one hand, the backbone of the scene was ready and we could get the false impression of completeness. On the other hand, the scene demanded ten times more time, given that every material had to be unique.
Thus, each brush was assigned a separate materialModels were unwrappedIt wasn't planned to use uv-maps as a guides for texture painting in the image editor. Uv-coordinates were needed primarily for seamless textures. Accordingly, the texture seam was hidden out of camera sight.
Along with uv- coordinates for texture mapping I often used generated coordinates. The texture was placed with Mapping node. It was scaled, rotated, positioned and results were observed in real-time, using “rendered” viewportmode.

To project texture evenly and from several directions at once, switched projection method to «box». With the help of the Blend parameter textures seams were completely hidden.

MATERIAL STRUCTURE

Thus, the structure of the material was as follows:
Basic shader - uses neutral seamless texture and uv-coordinates.
Supplementary shaders (in other words, a set of mix-shaders). As a blending factor for each of these mix-shaders seamless black and white texture, so-called "mask",was used.

Often, procedural coordinates were used (generated or object).
There are about 3 additional shaders in every material: dirt, paint, scratches.

For markings, text, images I used additional uv-map. With the help of the“attributes” node switched uv-map in the material editor, using vector output.

MATERIAL OF THE JAR

Material of the jar can be decomposed into the following elements:
1. Two basic materials - glass and paint
2 . Both of these materials have several composite materials
3 . The glass material consists of a glass and dust, dirt, fingerprints
4 . The paint material consists of a translucent, diffuse, reflective, emissiveshaders. Consequently, it uses diffuse, bump, translucency texture, etc.
5 . Transparency texture in the paint material determines what areas aretranslucent (covered with a thin layer of the paint), and what areas are opaque.
6.  Displacement map, which is also used as the normal map

LIGHTING
As a key light source the sun lamp was used. Shadows were soft - sample size 12 cm.

As a supportive light source, emissive plane was placed at the window, giving a soft lighting. Brush tops were lit separately with a spot light. Unfortunately, Cyclesdoesn't have something similar to Directional Light yet (sun and spot lamps are similar in function but also not quite the same). So, I had to add spot lights or invent obstacles between the object and the sun, to restrict its area of ​​influence.

As a key light source the sun lamp was used. Shadows were soft - sample size 12 cm.
As a supportive light source, emissive plane was placed at the window, giving a soft lighting. Brush tops were lit separately with a spot light. Unfortunately, Cyclesdoesn't have something similar to Directional Light yet (sun and spot lamps are similar in function but also not quite the same). So, I had to add spot lights or invent obstacles between the object and the sun, to restrict its area of ​​influence.

Spherical HDRi image softly illuminates the scene from all angles and creates virtually no shadows - it's good for us in this case. What is very important about HDRi – that the reflective parts of the brushes and also the jar begin to reflect theparticularly bright areas of the HDRi. These reflections accentuate objects' volume and make a metal act like a "metal", if you know what I mean.
Rotated HDRi using mapping node, searching for the most effective angle.

HAIR SIMULATION

Let's briefly explore the process of creating the hair.
1. The ferrule-shaped plane was created. On top of this plane sit the particle system with hair. Since the plane itself isn't visible by the camera, it wasn'tseparated from the particle system.
2. Emitter type – hair
3. Hair length and density. The optimal value is almost impossible to guess, we should prepare ourselves for the inevitable return to this stage.
4. Adaptive rendering - hair geometry adapts to the resolution and depends on the minimal bending of the original geometry. These values ​​influence the polycount during the rendering. It's important to remember this, to squeeze the scene in memory limit for fast GPU-rendering.
5. Cycles Hair Rendering. Ribbons
6. Set Children to Interpolated. Display – 2-5, Render – 2-5. Final values depend on desired hair density and computer characteristics. While children are activated, every “parent” hair is spawning several “child” hairs. Parameter called “uniform” in roughness controls, how chaotic this hairs will be.
7. Set Kink to Curl mode.
8. Other values can be default.

10Now we're switching viewport to Particle Edit mode and trying ourselves as a stylists, cutting and combing hair.

HAIR MATERIAL

There is now a special shader for hair — in Blender 2.69. In transmission mode itlooks very believable. But, at least on my computer, often crashes Blender and looks very demanding with respect to the render time. In some cases, this shader causes the scene to render 2-3 times longer. However, for the final compose Iseparately rendered the brushes hair using this shader, because in the end it was worth it.

The node called Hair Info in material editor is essential when texturing hair.
Using Intercept attribute and Color Ramp (gradient), we can control the gradientof the hair color - from the roots to the tips. Note that the gradient may haveseveral "stops".

Combining this information with the capabilities of uv-coordinates, we can confidently dye our hair - using length (Intercept) and location relative to theparticle emitter (UV).

RENDER

Since the scene tended to photo-realism, I decided to leave the caustic enabled and the maximum number of bounces untouched (8).
Used classical path tracing, and not the branched version as it was more conventional for me. Perhaps now would have done otherwise, since branched path tracing coupled with manual tweaking light sources samples solves the problem of noise in shadows. Spot lamps and perhaps any lamps generate much noise if there is a lot of obstacles between them and the camera.

 

Render was infernally slow: on my computer (i7 3690, 16gb ram, nvidia 650m) it was rendering about two days in the resolution of 1100-2200 (12,000 samples).

 

Reasons:

 

* complex and sometimes bad-planned materials

 

* the bounces number was too high

 

* new shader hair

 

* high hair density

 

* classic path tracing in interior scene with lots of light and reflections and with lots of objects between the sun and the camera

 

Also, the situation has been so fun because I decided to minimize the amount of post-processing.

 

Though, I've been lucky — guys from Renegatt (GPUBOX software) helped me out to do a test renders and a final render. Thanks a lot!

 

COMPOSE AND POSTPROCESSING

 

For composing, used Blender compositor.

 

Let's see how the processing sequence is done.

 

1. The jar (brightness, contrast). Material ID served as a mask.

 

2. Table. Intensified sunlight (using Diffuse Direct render pass).

 

3. Hair (brightness, contrast).

 

4. Fog (a little bit), using Mist pass

 

5. Foreground – made brighter.

 

6. Glare

 

7. Chromatic aberration - the effect of the spectral shift at the edges of the picture (GS)

 

8. Dust

 

9. Vignetting

 

10. Curves

 

11. Saturation

Last stage - cosmetic treatment. Brightness tweaks, lightening / darkening —polished the image till it was looking niceThat concludes the making-of The Brushes.

www.blender-game.com

 

2765 Автор:
Актуальность: 0
Качество: 0
Суммарный балл: 0
Голосов: 0 оценки
Зарегистрируйтесь, чтобы добавить комментарий.
Эту страницу просмотрели: * уникальных посетителей