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Exclusive: Validating an Experimental Shortcut Interface with Flaming Arrows & Paper Planes



Last time, we detailed our initial explorations of single-handed shortcuts systems. After some experimentation, we converged on a palm-up pinch to open a four-way rail system. Today we’re excited to share the second half of our design exploration along with a downloadable demo on the Leap Motion Gallery.

Guest Article by Barrett Fox & Martin Schubert

Barrett is the Lead VR Interactive Engineer for Leap Motion. Through a mix of prototyping, tools and workflow building with a user driven feedback loop, Barrett has been pushing, prodding, lunging, and poking at the boundaries of computer interaction.

Martin is Lead Virtual Reality Designer and Evangelist for Leap Motion. He has created multiple experiences such as Weightless, Geometric, and Mirrors, and is currently exploring how to make the virtual feel more tangible.

Barrett and Martin are part of the elite Leap Motion team presenting substantive work in VR/AR UX in innovative and engaging ways.

We found the shortcuts system comfortable, reliable, and fast to use. It also felt embodied and spatial since the system didn’t require users to look at it to use it. Next it was time to put it to the test in a real-world setting. How would it hold up when we were actually trying to do something else with our hands?

We discussed a few types of potential use cases:

#1. Direct abstract commands. In this scenario, the system could be used to directly trigger abstract commands. For example, in a drawing application either hand could summon the shortcut system – left to undo, right to redo, forward to zoom in, or backwards to zoom out.

#2. Direct contextual commands. What if one hand could choose an action to take upon an object being held by the other hand? For example, picking up an object with your left hand and using your right hand to summon the shortcut system – forward to duplicate the object in place, backward to delete it, or left/right to change its material.

#3. Tool adjustments. The system could also be used to adjust various parameters of a currently active tool or ability. For example, in the same drawing application your dominant hand might have the ability to pinch to draw in space. The same hand could summon the shortcut system and translate left/right to decrease/increase brush size.

#4. Mode switching. Finally, the system could be used to switch between different modes or tools. Again in a drawing application, each hand could use the shortcut system to switch between free hand direct manipulation, a brush tool, an eraser tool, etc. Moreover, by independently tool-switching with each hand, we could quickly equip interesting combinations of tools.

Of these options, we felt that mode switching would test our system the most thoroughly. By designing a set of modes or abilities that required diverse hand movements, we could validate that the shortcuts system wouldn’t get in the way while still being quickly and easily accessible.

Mode Switching and Pinch Interactions

In thinking about possible abilities we’d like to be able to switch between, we kept returning to pinch-based interactions. Pinching, as we discussed in our last blog post, is a very powerful bare handed interaction for a few reasons:

  • It’s a gesture that most people are familiar with and can do with minimal ambiguity, making it simple to successfully execute for new users.
  • It’s a low-effort action, requiring only movement of your thumb and index fingers. As a result, it’s suitable for high-frequency interactions.
  • Its success is very well-defined for the user who gets self-haptic feedback when their finger and thumb make contact.

However, having an ability triggered by pinching does have drawbacks, as false triggers are common. For this reason, having a quick and easy system to enable, disable, and switch between pinch abilities turned out to be very valuable. This led us to design a set of pinch powers to test our shortcut system.

Pinch Powers!

We designed three pinch powers, leaving one shortcut direction free as an option to disable all pinch abilities and use free hands for regular direct manipulation. Each pinch power would encourage a different type of hand movement to test whether the shortcut system would still function as intended. We wanted to create powers that were interesting to use individually but could also be combined to create interesting pairs, taking advantage of each hand’s ability to switch modes independently.

The Plane Hand

For our first power, we used pinching to drive a very common action: throwing. Looking to the physical world for inspiration, we found that paper plane throwing was a very expressive action with an almost identical base motion. By pinching and holding to spawn a new paper plane, then moving your hand and releasing, we could calculate the average velocity of your pinched fingers over a certain number of frames prior to release and feed that into the plane as a launch velocity.

Using this first ability together with the shortcuts system revealed a few conflicts. A common way to hold your hand while pinching a paper plane is with your palm facing up and slightly inwards with your pinky furthest away from you. This fell into the gray area between the palm direction angles defined as ‘facing away from the user’ and ‘facing toward the user’. To avoid false positives, we adjusted the thresholds slightly until the system was not triggered accidentally.

To recreate the aerodynamics of a paper plane, we used two different forces. The first added force is upwards, relative to the plane, determined by the magnitude of the plane’s current velocity. This means a faster throw produces a stronger lifting force.

The other force is a little less realistic but helps make for more seamless throws. It takes the current velocity of a plane and adds torque to bring its forward direction, or nose, inline with that velocity. This means a plane thrown sideways will correct its forward heading to match its movement direction.

With these aerodynamic forces in play, even small variations in throwing angle and direction resulted in a wide variety of plane trajectories. Planes would curve and arc in surprising ways, encouraging users to try overhanded, underhanded, and side-angled throws.

In testing, we found that during these expressive throws, users often rotated their palms into poses which would unintentionally trigger the shortcut system. To solve this we simply disabled the ability to open the shortcut system while pinching.

Besides these fixes for palm direction conflicts, we also wanted to test a few solutions to minimize accidental pinches. We experimented with putting an object in a user’s pinch point whenever they had a pinch power enabled. The intention was to signal to the user that the pinch power was ‘always on.’ When combined with glowing fingertips and audio feedback driven by pinch strength, this seemed successful in reducing the likelihood of accidental pinches.

We also added a short scaling animation to planes as they spawned. If a user released their pinch before the plane was fully scaled up the plane would scale back down and disappear. This meant that short unintentional pinches wouldn’t spawn unwanted planes, further reducing the accidental pinch issue.

The Bow Hand

For our second ability we looked at the movement of pinching, pulling back, and releasing. This movement was used most famously on touchscreens as the central mechanic of Angry Birds and more recently adapted to three dimensions in Valve’s The Lab: Slingshot.

Virtual slingshots have a great sense of physicality. Pulling back on a sling and seeing it lengthen while hearing the elastic creak gives a visceral sense of the potential energy of the projectile, satisfyingly realized when launched. For our purposes, since we could pinch anywhere in space and pull back, we decided to use something a little more lightweight than a slingshot: a tiny retractable bow.

Pinching expands the bow and attaches the bowstring to your pinched fingers. Pulling away from the original pinch position in any direction stretches the bowstring and notches an arrow. The longer the stretch, the greater the launch velocity on release. Again we found that users rotated their hands while using the bow into poses where their palm direction would accidentally trigger the shortcut system. Once again, we simply disabled the ability to open the shortcut system, this time while the bow was expanded.

To minimize accidental arrows spawning from unintentional pinches, we again employed a slight delay after pinching before notching a new arrow. However, rather than being time-based like the plane spawning animation, this time we defined a minimum distance from the original pinch. Once reached, this spawns and notches a new arrow.

The Time Hand

For our last ability, we initially looked at the movement of pinching and rotating as a means of controlling time. The idea was to pinch to spawn a clock and then rotate the pinch to turn a clock hand, dialing the time scale down or back up. In testing, however, we found that this kind of pinch rotation actually only had a small range of motion before becoming uncomfortable.

Since there wasn’t much value in having a very small range of time-scale adjustment, we decided to simply make it a toggle instead. For this ability, we replaced the pinch egg with a clock that sits in the user’s pinch point. At normal speed the clock ticks along quite quickly, with the longer hand completing a full rotation each second. Upon pinching, the clock time is slowed to one-third normal speed, the clock changes color, and the longer hand slows to complete a full rotation in one minute. Pinching the clock again restores time to normal speed.

Continued on Page 2: Mixing & Matching

The post Exclusive: Validating an Experimental Shortcut Interface with Flaming Arrows & Paper Planes appeared first on Road to VR.



Bitcoin Difficulty Ribbon Could Indicate Imminent Price Increase



One is called the difficulty ribbon, and it has just broken out of the green buy zone for the first time since March in terms of compression. The metric was reported by analytics provider Glassnode, which added that historically, these had been periods characterized by a positive momentum indicating significant price increases.

Historical Bitcoin Buy Signal

The Bitcoin difficulty ribbon was created by chartist Willy Woo. It consists of simple moving averages of network difficulty enabling the rate of change of difficulty to be easily seen. Periods of high ribbon compression, such as the current situation, have been historically good buying opportunities.

There have been several significant price increases over Bitcoin’s lifespan that followed this ribbon compression breaking out of the green zone. The most recent was around April 2019 when BTC prices surged from below $5k to top out over $13k just three months later.

It was also observed that there had been a massive divergence in difficulty ribbon compression and Bitcoin price over the past six years. However, the chart has used a logarithmic price chart, which may have caused that anomaly.

Bitcoin’s hash ribbon is a similar metric, and CryptoPotato reported that it was flashing buy signals back in July. In the five weeks that followed, BTC price surged 34% to make its 2020 high.

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BTC Price Action Update

Looking at the shorter term, Bitcoin’s price chart has just printed another ‘Bart Simpson’ pattern with a sharp 2.3% decline in just over an hour, wiping Monday’s gains.

Prices had recovered to $10,725 at the time of writing, and sentiment appears to be bullish for BTC, according to a recent poll by analyst and trader Josh Rager.

Bitcoin is currently trading right on the 50-day moving average, which is acting as resistance at the moment. The next step above this is a break above $11k, while on the low side, there is strong support at the $10k level. Analyst ‘CryptoHamster’ added:

“After the breakout the resistance line became support. Now it is getting tested. If it holds, it would be a very nice sign. But it has to hold, otherwise the whole growth is just a short squeeze.”

Short term charts suggest price could go either way, but longer-term on-chain analytics, such as the difficulty ribbon, are more bullish.


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Bulgarian National Convicted For His Role in a Bitcoin-Related Crypto Exchage Scam



The owner of a cryptocurrency exchange has been recently convicted in a transnational scheme of defrauding people through an online auction fraud. Court says the scam reached a multi-million dollar scale.

At Least 900 Americans Victimized

As per a recent report, people who suffered from the fraud were probably more than 900 American citizens. According to the official statement, 53-years-old Rossen Iossifov, formerly of Bulgaria and reported owner of a Bulgaria-based Bitcoin exchange R.G. Coins, was convicted of both conspiracy to commit racketeering and money laundering. After a two-week trial, the jury in Frankfort, Kentucky and U.S. District Judge Robert E. Wier scheduled the sentencing to Jan 12, 2021.

Reportedly, some of the Romania-based members of the group posted a false advertisement to promote an online auction and sales websites, among which Craigslist and eBay. The ad promised its victims high-cost goods (typically vehicles) that did not exist.

As per the release, members of the scam would use stolen identities to promote and convince their victims to send money for the advertised items via “persuasive narratives”. For example, some of the ads had impersonated a military member in need of selling the advertised item before deployment.

The scammers also provided invoices with trademarks of reputable companies to their victims, making the transactions seem legit. The legal document also reveals that members of the conspiracy set up call centers, offering customer support. This way they would provide advice to client questions and “alleviate concerns over the advertisements”.

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Converting The Stolen Funds Into Crypto Assets

According to the official statement, once Iosiffov received the victims’ funds, he and his fellows would convert them into crypto assets and transfer them to off-shore money launderers.

As per the court documents, “since at least September 2015 to December 2018, the Bulgarian exchanged crypto assets into local fiat currency on behalf of his Romania-based partners in the scam, knowing that Bitcoin presented the proceeds of illegal activity.”

According to the court statement, in just two and a half years, Iossifov exchanged more than $4.9 million worth of Bitcoin for only four of the members of the criminal team.

A total of seventeen defendants have been convicted in the case. Three others are fugitives. Police departments in the U.S. and Romania have led the procedures on the case.

It’s worth noting that the US DOJ is becoming increasingly active in pursuing crypto-related fraud. As CryptoPotato reported earlier, it went after 280 cryptocurrency accounts related to hackers from North Korea.

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Aave Governance is Now on Mainnet: Incoming 100:1 Token Split For LEND?



The Aave Money Market DeFi protocol is now about to be more decentralized than ever. In an announcement published on its official blog on 25th September 2020, the team reported on the successful launch of the Aave Governance on the mainnet.

This means that users of the protocol will now be able to vote on critical decisions for the project’s future. As Aave explains, the governance implementation was active in the Kovan and Ropsten testnets, giving users the ability to experiment with how to participate in the voting process for various improvement proposals, known as AIP.

Bye LEND Welcome AAVE tokens: Aave’s First Proposal

Unlike testnet implementations, the effects of launching governance on the mainnet are now more formal and reflect the commitment of the development team to empowering the community. The first AIP for which users will be able to vote involves a token migration and the total supply reconversion.

Should the first AIP be approved, the LEND tokens will become AAVE tokens, and the total supply will drop by 100:1. While this may give the impression of less liquidity, the reality is that the value or market cap should, in theory, remain the same as the AAVE holdings in the owners’ wallets would also decrease proportionally.

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“The major benefits of the migration is that we activate the Safety Module, meaning that AAVE token holders can stake their AAVE and earn,” told us Aave CEO, Stani Kulechov.

These modules are created to secure the protocol and would be used to recapitalize the platform in case of a deficit.

Will exchanges support the Lend – Aave migration? According to Kulechov, “Major exchanges will support after the migration is complete; however, they will separately announce on the support.”

More Incentives for the Community

The Aave team also plans to put under consideration the possibility of including part of the fees within these Safety Modules. In this way, it is guaranteed that the security of the protocol increases with its usability.

Kulechov, Aave CEO. Source: Twitter

“The SM will act as a recapitalization mechanism, so in the case of a shortfall event, your stake may be slashed up to 30% to cover the deficit. The idea behind “safety mining” is to reward community members who stake their AAVE to promote the safety of the protocol.

In addition to the Safety Incentives, users would have the opportunity to earn Ecosystem Incentives (EI) for supplying and borrowing assets from within the platform. They hope that the community will also be able to decide how to distribute specific incentives in the near future.

Aave is one of the longest-running DeFi protocols in the ecosystem. It allows users to lend and borrow certain assets, putting others as collateral. However, interests are automatically determined by supply and demand according to parameters coded within the protocol.

Besides, Aave became famous for allowing flash loans. This mode allows a person to take an unsecured loan on the condition that it is repaid before the next block is mined.

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