Hristo Zaprianov, Developer in Sofia, Bulgaria
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Hristo Zaprianov

Verified Expert  in Engineering

Software Developer

Sofia, Bulgaria
Toptal Member Since
May 21, 2022

Hristo is a software developer and virtual reality mastermind, spending his workdays dreaming of the future and living it in virtual reality. He always tries to combine the pieces the right way to unlock their full potential and create what was previously unimaginable. Hristo has prototyped and tested different VR use-cases, figured out the most immersive and impactful solutions, and built bespoke 3D, VR, AR, and mobile apps for clients. He will be a great asset to any team.


Zap Zone Ltd.
Unity, Virtual Reality (VR), Augmented Reality (AR), Mixed Reality (MR), HLSL...
Unity, Virtual Reality (VR), Oculus Go, Oculus Rift, Oculus Quest...
Interconsult Bulgaria
OpenSceneGraph, OGRE, Unity, GLSL, HLSL, Cg, C++, C#, Microsoft HoloLens...




Preferred Environment

Windows, Slack

The most amazing...

...thing I've developed is the Kongsberg Maritime engine room simulator, giving me profound technical expertise, management, and client communication skills.

Work Experience

Owner and Contractor

2016 - PRESENT
Zap Zone Ltd.
  • Developed the new 2022 version of the 3D part of Kongsberg Maritime's engine room simulator from scratch.
  • Created the proof of concept and tech demo of an augmented reality (AR) app to assist children in learning English for Pearson.
  • Developed a mobile app to showcase Arteks' 17-story Diamant building. The app features a detailed, interactive 3D model of the building, apartment views, walkthroughs, and some AR functionality, such as the detection of blueprints.
  • Created an infotainment kiosk app that can be seen at, for Solvay's booth at a convention in China, showcasing their battery technology for mobile phones.
  • Built an AR app for custom food orders. The app can be seen at, and it allows users to choose ingredients. The app was developed to cater to a big event organized by Julius Bär, a Swiss private bank.
  • Created a mobile storytelling app that can be seen at, for children's books for a private client from Switzerland.
Technologies: Unity, Virtual Reality (VR), Augmented Reality (AR), Mixed Reality (MR), HLSL, GLSL, Cg, Oculus Quest 2, C#, Android, iOS, ARCore, ARKit, Vuforia, Mobile

Virtual Reality (VR) Developer

2019 - 2021
  • Created virtual reality prototypes and worked on product discovery in the fields of data visualization, health care, and virtual meetings.
  • Developed applications for virtual safety training for different clients, including breweries and steel manufacturing plants.
  • Worked on prototypes for forklift and mining machines operation training.
  • Collaborated with Coca-Cola Bulgaria on a virtual meeting prototype.
  • Used several VR headsets from Oculus, including Go, Rift, Quest, and Quest 2, and created a tool for Oculus Avatars recording.
  • Worked on custom tools to use in VR development like laser pointers and more.
Technologies: Unity, Virtual Reality (VR), Oculus Go, Oculus Rift, Oculus Quest, Oculus Quest 2, C#, Virtual Reality ToolKit (VRTK), 3D, Game Development, WebGL

Team Lead

2008 - 2019
Interconsult Bulgaria
  • Worked on advanced environmental effects like rain, water, snow, mist, etc., for Kongsberg Maritime's Nemo ship simulator, using OpenGL Shading Language (GLSL) Shaders in 2008.
  • Worked as a tech lead on Kongsberg Maritime's engine room simulator from 2009. Used OpenSceneGraph (OSG) and GLSL Shaders first, then OGRE 3d, DirectX 9, and HLSL Shaders. Rebuilt everything in 2011 using Unity 3 and improved on it until I left.
  • Created a Microsoft HoloLens app for Coca-Cola EMEA, showing how technology could be used in the future to assist and improve the stocking of stores according to sales numbers. It won the Global Tech Summit 2018 "Innovation of the Year" award.
  • Worked on several prototypes and proofs of concept for virtual and mixed reality fields using HTC Vive and Microsoft HoloLens.
Technologies: OpenSceneGraph, OGRE, Unity, GLSL, HLSL, Cg, C++, C#, Microsoft HoloLens, HTC Vive, Virtual Reality (VR), Mixed Reality (MR), IT Project Management, Agile Product Management, 3D, Game Development

Graphics Programmer

2007 - 2008
  • Gained my first experience working with console development kits.
  • Worked on chess mini-games for the Nintendo DS version of Chessmaster.
  • Worked on chess mini-games for the Xbox version of Chessmaster.
  • Worked on the sound management system for the Xbox version of Chessmaster.
Technologies: OpenGL, OpenGL ES, GLSL, Xbox, Nintendo DS, C++, 3D, Game Development

Engine Room Simulator

The Kongsberg Maritime simulator is used for training marine engineers as it simulates the process of going inside the ship during operation. It trains users on what to do in emergencies without risking the ship and personnel.

Coca-Cola HoloCooler
A mixed reality app using Microsoft HoloLens, developed for a Coca-Cola EMEA big brass event. It shows how technology could be used in the future to assist and improve the stocking of stores according to clients' needs and sales numbers.
It also won the "Innovation of the Year" award at the Global Tech Summit 2018, a big tech event in Bulgaria.

Virtual Reality (VR) Developer
Custom tool for recording Oculus, now Meta, Avatars. The use-cases are many and diverse, like:

• Have an avatar that greets the user and guides him through your experience.
• Simulate different scenarios in environments like classrooms, workplaces, public institutions, banks, hospitals, and so on.
• Use avatars to teach or demonstrate certain actions inside your application.
• Play different recordings as reactions to your user's actions.
• Use recorded avatars to aid the development and testing of your application.
• Use Avatars as NPCs.

The source is free and available to the public. The link is in the Medium article.
2000 - 2006

Master's Degree in Computer Science

RWTH Aachen University - Aachen, Germany


OpenGL, DirectX, WebGL, OpenGL ES


Slack, OpenSceneGraph


Unity, ARKit, Unity3D, Microsoft Kinect, OGRE


Oculus Rift, Windows, ARCore, Vuforia, Xbox, Nintendo DS, Android, iOS, Oculus, Mobile


C#, GLSL, HLSL, C++, Cg


Agile Product Management, GPGPU, Mobile Development


Programming, Computer Graphics, Computer Science, Algorithms, Virtual Reality (VR), HTC Vive, Oculus Quest, Oculus Quest 2, Augmented Reality (AR), IT Project Management, 3D Graphics, Unity3D Native Plugin Interface, Complexity Theory, Microsoft HoloLens, Oculus Go, Mixed Reality (MR), Azure Kinect DK, Game Development, Virtual Reality ToolKit (VRTK), Gaming, 3D

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