Blend4web

Preparing audio-visual content for Blend4Web is done in the Blender 3D modeling and animation package. Content is reproduced via WebGL , Web Audio and other standard browser technologies, without using any extensions ^[2] .

The framework is distributed under dual licensing , under open GPLv3 and commercial licenses. The source code is in the repository on GitHub ^[3] .

A 3D scene is created in Blender and exported as a JSON file and a binary file for later download by the web application . The scene can also be exported as a single self-contained HTML file, into which the exported data is packed, the user interface of the web player and the executable code ^[4] . Export in HTML format is considered as the easiest way to work with Blend4Web ^[5] . A summary file with a minimum size of the order of 1 MB can be placed on a web page using the standard <iframe> element ^[6] . Blend4Web-based web applications can be deployed in popular social networks such as Facebook ^[7] and VKontakte .

The Blend4Web software components include JavaScript libraries , an addition to Blender, and a set of tools for configuring 3D scene settings, debugging, and optimization.

The development of Blend4Web was started by the Moscow company Triumph in 2010. The first public release took place on March 28, 2014 ^[8] .

At the end of 2017, project founders Yuri and Alexander Kovelenov left the company and began developing a new product, Verge3D ^[9] .

The framework contains a number of components commonly found in game engines , including a sound source positioning system, a physics engine ( fork of the Bullet physics engine, ported to JavaScript ), an animation system, and an abstraction layer for programming game logic ^[10] .

Up to 8 animations of various types can be assigned to each object, including skeleton and vertex animation. The speed and direction of the animation, as well as the parameters of the particle systems (size, initial velocity and number) can be set using the API ^[11] .

Dynamic loading and unloading of data, lighting maps are supported, there is the possibility of simulating subsurface scattering ^[12] .

There are solutions for rendering outdoor scenes, including simulating the effects of wind, simulating water, atmospheric effects. The work of this functionality is demonstrated in the Ferma demo video , in which there are also numerous animated non-game characters , the ability to move around the location from a first-person perspective, the interaction with objects and vehicle control are implemented ^[13] .

Due to the use of WebGL cross-browser technology, Blend4Web works in all major ^[14] browsers , including mobile devices ^[15] . However, browsers with an experimental implementation of the WebGL standard, such as Internet Explorer , do not fully support the capabilities of Blend4Web ^[16] . There are applications that can work in the Tizen operating system, in particular, on the Samsung Gear S2 smart watch ^[17] .

Among the non-trivial features for browser frameworks are the following: optimization by combining draw calls, optimization of hidden objects by clipping, putting physical calculations into a separate execution flow , simulating the behavior of sea waves ^[18] .

In version 14.09, Blend4Web implements the ability to implement interactivity in 3D scenes using a tool for visual programming . The tool resembles Blender’s built-in game engine logic editor, in particular, as in BGE, visual logic blocks are used in the Blender interface. Animation sequences created by the artist are played in response to user interaction with certain three-dimensional objects ^{[19] [20]} .

Starting from version 15.03, Blend4Web supports attaching two-dimensional HTML elements (for example, information windows) to 3D objects (so-called annotations), as well as copying objects while the application is running (instantiating, English instancing ) ^[21] .

Among the effects on the basis of post-processing are supported luminous surfaces ( eng. Glow ), glare glare ( bloom ), depth of field of the camera , twilight rays , motion blur and mutual shading ( SSAO ) ^[22] .

Support for virtual reality devices was implemented at the end of 2015. The work of the Oculus Rift helmet is provided by the WebVR experimental API. ^[23]

The add-on for Blender is written in Python and C , and can be compiled for Linux x86 / x64, OS X x64 and MS Windows x86 / x64 platforms.

Profile settings Blend4Web is activated in the add-on settings. When switching to a profile, the Blender interface is rebuilt while all unsupported settings are deleted ^[24] .

Blend4Web supports a number of Blender-specific functions, such as the nodal editor of materials (a tool for visual programming shaders ) ^[25] and a particle system ^[26] . There is also initial support for the non-linear animation editor (NLA) as part of the Blender package for creating simple scripts.

To obtain a similar visual result in the editor and in the browser ( WYSIWYG ), users are recommended to switch to the GLSL rendering mode available in Blender ^[27] .

Blender Game Engine

Like the built-in Blender game engine (Blender Game Engine, BGE), Blend4Web loads the scene data prepared in Blender without using any intermediate editor ^[5] . Blend4Web-based applications are designed to work in browsers, while BGE executables run outside of browsers ^{[28] [29]} . The Blend4Web APIs are implemented in JavaScript , in contrast to the Python -based APIs of the built-in Blender engine. Instead of the visual logic editor BGE, which is not supported in Blend4Web, the latter assumes the use of standard approaches adopted in web development.

Unity

In Unity, the ability to export to WebGL is available from version 5 ^[30] . The implementation of WebGL support, however, is experimental, in particular, in the WebGL version, in the near future, no support is planned for mobile devices, sound source positioning systems, video textures ^[31] .

Three.js

The Three.js WebGL library requires writing code to perform trivial tasks, which raises the threshold of entry and extends learning; In Blend4Web, most of the work involved in preparing online presentations does not require programming ^[32] .

NASA has developed an interactive web application for the third anniversary of the landing of the rover Chiuriositi ^[33] . The application ^[34] , created on the basis of Blend4Web, implemented the rover movement, camera and manipulator control, and also reproduced some known mission events ^{[35] [36]} . The application was presented at the beginning of the WebGL section at the SIGGRAPH 2015 conference ^[37] .

• blend4web.com/ru - the official site Blend4Web