Definition: Microsoft HoloLens is a standalone mixed reality headset (head-mounted display). It shows digital 3D content directly in the real environment. Unlike VR headsets, the real world stays visible. Digital holograms are placed over reality (augmented reality).
HoloLens is designed for enterprise applications: remote assistance (the expert sees what the technician sees), hands-free instructions (maintenance steps appear during the work), design reviews (virtual 3D models in the real environment) and training. The device is fully self-contained – no PC and no smartphone are necessary.
HoloLens 2 (current version since 2019): larger field of view, more precise hand tracking, more comfortable, price approx. €3,500–4,500.
English: HoloLens, mixed reality headset German: HoloLens, Mixed-Reality-Brille
Technology
Holographic Processing Unit (HPU)
A special co-processor for holographic calculations: - Processes sensor data in real time - Detects the spatial environment (spatial mapping) - Renders holograms with <10 ms latency - Fuses sensor inputs (cameras, depth sensors, IMU)
Sensors and cameras
HoloLens captures the environment with several sensors: - Time-of-flight depth sensor: spatial depth measurement - 4 environment cameras: 360° tracking - Eye tracking (HoloLens 2): gaze tracking for interaction - IMU (inertial measurement unit): motion detection - Microphones (5): directional audio, voice control
Spatial mapping
HoloLens creates a 3D map of the environment: - Detects floors, walls, tables and machines - You can place holograms on real surfaces - Virtual objects collide with real objects (occlusion) - Persistence: rooms that you scan once stay saved
Hand tracking
Gesture control without controllers: - Detects hand position and gestures - "Air tap" for selection - Grab and move holograms - More intuitive than controllers
Display technology
Optical see-through display: - Semi-transparent waveguide displays - Holograms placed over reality - Field of view: 43° horizontal, 29° vertical (HoloLens 2) - Resolution: 2K per eye
Applications in Mechanical Engineering
Remote assistance and expert support
HoloLens enables remote support:
Scenario: A service technician on site has a problem with a machine. The expert is not on site.
Workflow: 1. The technician wears the HoloLens 2. The expert connects remotely (Microsoft Dynamics 365 Remote Assist) 3. The expert sees what the technician sees (first-person view) 4. The expert draws hints in the technician's field of view (arrows, circles, text) 5. The technician sees the hints as an AR overlay on the real machine
Advantage: - Hands-free: the technician has both hands free for the work - Precise communication: "Turn the screw at the top left" → an arrow points directly at it - Fewer on-site visits by experts - Faster problem solving
Hands-free maintenance instructions
Step-by-step instructions appear during the work:
Application: The maintenance of a complex machine needs many steps.
HoloLens solution: - Instructions as an AR overlay directly on the machine - Step 1 shows which screw to loosen (visual marker) - After you complete it, step 2 appears automatically - Videos and animations show the movements - The technician follows the instructions with both hands free
Advantage over a tablet: - No looking back and forth between tablet and machine - Context-related hints directly on the object - Hands free for tools
Design reviews and prototyping
Evaluate virtual 3D models in the real environment:
Application: A new machine is still in development. No physical prototype is available.
HoloLens workflow: 1. Load the CAD model as a hologram 2. Place it at true scale in the production hall 3. Stakeholders (development, production, customer) wear HoloLens devices 4. They walk around the virtual model together 5. They evaluate size, accessibility and integration 6. They mark changes
Advantage: - Early validation without an expensive prototype - Better spatial understanding than on a screen - Collaborative: several people see the same hologram
Training and onboarding
Interactive training experiences:
Application: New employees learn to operate a machine.
HoloLens training:
- Virtual machine as a hologram
- The trainee practices operating procedures hands-free
- The system gives feedback on errors
- No danger (no risk to the real machine)
Or:
Training on the real machine with AR overlays:
- Hints show where switches and levers are
- Safety notes appear
- Step-by-step guidance
Quality control and inspection
Visual inspection support:
Application: Quality inspection of complex assemblies.
HoloLens support:
- The target position appears as a hologram over the actual object
- Deviations become visible
- You can complete checklists hands-free
- Photos and videos document the findings
HoloLens vs. Alternative AR Devices
HoloLens vs. tablet/smartphone AR
HoloLens advantages:
- ✅ Hands-free (both hands free)
- ✅ Context-related display (overlay directly on the object)
- ✅ Spatial tracking (precise in 3D)
Tablet/smartphone advantages:
- ✅ Less expensive (tablet ~€500 vs. HoloLens ~€4,000)
- ✅ Easier to use (touch is familiar)
- ✅ No acceptance barrier (everyone knows tablets)
When to use HoloLens: hands-free work is critical (maintenance, assembly), remote assistance, long sessions.
When to use a tablet: occasional AR use, product presentations, budget constraints.
HoloLens vs. AR glasses (Epson Moverio, RealWear, Vuzix)
HoloLens advantages:
- ✅ Better hologram quality
- ✅ More precise spatial mapping
- ✅ Hand tracking (no controllers)
Advantages of alternative AR glasses:
- ✅ More robust (for harsh industrial environments)
- ✅ Longer battery life
- ✅ Less expensive (€1,000–2,500)
When to use HoloLens: premium experience, design reviews, complex holograms.
When to use alternatives: harsh environments (construction site, factory), long operating times, budget.
Total Cost of Ownership (TCO)
Purchase costs
- HoloLens 2: ~€3,500 (standard) to ~€4,500 (with Dynamics 365)
- Per technician/user: 1 device
- For Remote Assist: the expert does not need a HoloLens (a desktop or tablet is sufficient)
Software licenses
- Dynamics 365 Remote Assist: ~€65/month/user
- Dynamics 365 Guides: ~€65/month/user (maintenance instructions)
- Custom apps: development costs of €20,000–100,000 (depending on complexity)
Running costs
- Maintenance/support: ~10% of the hardware costs per year
- Updates: included in the Microsoft ecosystem
- Training: 1–2 days of familiarization per user
ROI calculation
Typical savings: - Remote Assist: 50–80% lower travel costs for experts - Maintenance time: 20–40% faster problem solving - Training: 30–50% less training time
Break-even: 6–18 months with regular use (>10 remote sessions per month).
Technical Requirements
Battery life
- Active use: 2–3 hours
- Standby: 2 weeks
- Solution: USB-C power bank for longer sessions
Connectivity
- Wi-Fi: 802.11ac (necessary for Remote Assist)
- Bluetooth: 5.0
- USB-C: data transfer, charging
Development
- Platform: Windows Mixed Reality, OpenXR
- Development: Unity, Unreal Engine, native (DirectX)
- Languages: C#, C++
Limitations and Considerations
Field of view
HoloLens 2 field of view: 43° × 29° (much smaller than the human field of view of 210° × 150°).
Effect: holograms are only visible in a limited area. For large objects, the user must turn their head.
Battery life
2–3 hours of active use.
Critical for: full-day operations (for example assembly).
Solution: a power bank or several devices.
Comfort
Weight: ~566 g (HoloLens 2). You can wear it, but it becomes a strain during use of several hours.
Better than: VR headsets (no isolation from the environment).
Acceptance
Some employees are skeptical about "putting on glasses".
Change management is necessary: start a pilot project with early adopters and demonstrate the added value.
Environmental conditions
- Light: works in all lighting conditions, also in darkness
- Dust/moisture: not IP-certified (for harsh environments, check alternatives)
Frequently Asked Questions (FAQ)
Is HoloLens suitable for every maintenance application?
No.
Ideal for: complex maintenance steps, remote assistance, hands-free requirements, frequent use.
Less suitable for: simple maintenance (a tablet is sufficient), rare use (the ROI is questionable), extremely harsh environments (more robust AR glasses are better), short ad-hoc tasks (the setup time is too long).
Rule of thumb: HoloLens pays off from >10 Remote Assist sessions per month or >20 complex maintenance jobs per month.
Can several users work together at the same time?
Yes.
Shared spatial anchors: several HoloLens users can see the same hologram and edit it together.
Remote collaboration: HoloLens user + remote expert (desktop/tablet).
Application: design reviews with stakeholders, joint problem solving, distributed teams.
Limitation: all users must be in the same Wi-Fi network (for local collaboration) or connected to the cloud (for remote collaboration).
How secure is HoloLens for confidential data?
Enterprise-grade security: Azure Active Directory integration, BitLocker encryption, Kerberos/certificate authentication, mobile device management (MDM).
Data privacy: cameras and sensors are only active when an app runs. There is no permanent recording.
Compliance: GDPR-compliant, ISO/IEC 27001.
Concerns: the camera can capture sensitive production areas.
Solution: policies for permitted usage zones, app-level permissions.
What happens to HoloLens data and apps when you change devices?
Cloud-based: apps and data are stored in Azure/Microsoft 365.
Device change: new HoloLens, same login → all apps and data are available.
Spatial anchors: saved room scans synchronize through the cloud.
Advantage: devices are interchangeable, and there is no data loss when the hardware fails.
Backup: automatic via the Microsoft cloud.
Is HoloLens worth it for small and medium-sized companies?
It depends on: frequency of use, travel costs, maintenance complexity.
ROI factors: if experts travel often (>10 times per year) → Remote Assist saves costs. If maintenance is complex and error-prone → hands-free guidance reduces errors. If the training effort is high → AR training is more efficient.
Alternative start: 1–2 devices as a pilot, measure the ROI, then scale.
Or: tablet AR as an entry point, then upgrade to HoloLens later.
Related Topics
AR/MR technologies:
- Augmented Reality – AR basics
- Mixed Reality – MR concepts
- Immersive Experiences – immersive applications
- Spatial Computing – computing in space
- Hand Tracking – gesture control
Applications:
- Remote Assistance – support from a distance
- Maintenance Guidance – maintenance instructions
- Design Review – virtual prototypes
- Training & Simulation – AR training
- Quality Inspection – quality control
Alternatives:
- Mobile AR – tablet/smartphone AR
- AR Smart Glasses – alternative AR glasses
- VR Headsets – virtual reality
- Projection AR – projection-based AR
- Handheld Devices – mobile devices
Business:
- TCO Analysis – total costs
- ROI Calculation – return on investment
- Change Management – acceptance & introduction
- Enterprise Deployment – company-wide rollout
- MDM Integration – device management
Technology:
- Spatial Mapping – capture of the room
- SLAM – Simultaneous Localization and Mapping
- LiDAR – depth sensing
- Optical See-Through – display technology
- 3D Model – hologram content
