I am François Bérard from the University of Grenoble Alpes.
With Thibault Louis, Jocelyne Troccaz and Amélie Rochet-Capellan we worked on GyroSuite:
General-Purpose Interactions for Handheld Perspective Corrected Displays, or HPCDs for short.
Here you have an HPCD: the display is held with both hands.
The viewpoint on the scene is continuously updated according to the positions of the display and the user.
This creates a strong illusion of presence of the virtual objects.
Compared to Virtual and Augmented Reality, an HPCD offer a smaller field of view,
but it seems to provide more comfort and precision.
This could make HPCDs suitable for applications such as 3D modelling.
But for this, general-purpose interactions must be designed.
In this work, we want to provide buttons, scales, hierarchical menus, and control panels for two-handed HPCDs,
and we also investigated object selection and scene zooming.
Previous work on HPCDs has been focused mainly on viewpoint and object control.
Our work also relates to recent work in VR that explored the use of a two-handed tangible as input.
But here again, this was only for viewpoint and object control.
Our design process was based on trial and error from informal user feedback during the past three years.
And we also ran a qualitative user evaluation.
I will now introduce our design.
We worked with the porthole metaphor where the display reveals the scene inside and behind it.
All of the interactions that we designed involve a cursor.
We used a 3D cross rigidly attached at the center of the sphere.
In direct pointing, users move the pointer inside the object.
They validate their selection by tapping with the index finger.
The object is then rigidly attached to the display and can be transformed with 6 degrees of freedom.
This is what this looks like on the actual system.
The index finger can be seen touching and releasing contact with the display.
For far away objects, we experimented with ray casting.
Users align the pointer with a distant object which becomes pre-selected with an outline.
If we attach the object to the display, this creates an unsuitable lever arm effect
causing the object to quickly disappear from the display
To alleviate this problem, we designed two different pointer behavior.
With proxy cursor, the pointer jumps to the object.
From then on, the transformation on the display are reproduced on the cursor and the object.
With the magnet cursor it is the object that jumps to the cursor on validation.
Here we show the magnet cursor on the actual system.
Because the cursor is inside the scene, objects in front of the cursor can also be selected.
As a result, direct pointing can be seen as a particular a case of the magnet cursor.
So, we combine them with no need for a mode switch.
We tested display rotations for scalar parameter control.
The yaw and roll rotations only afford small rotations and suffer from occlusions.
Pitch affords much larger rotations with no occlusion.
We used pitch to control the zoom factor of the scene.
Translations don't interfere with rotations so we use them to continuously update the zoom center.
For commands, we built a marking menu that pops up in front of the user after a double tap of the index finger.
We show a menu pointer at the intersection of the menu and the eye-cursor ray.
The menu is fixed in the physical world.
By moving the display, users move the pointer and make their selection with crossings.
Here we show a two-level marking menu that triggers standard views
We also designed a control panel. This one remains attached to the eye-cursor ray.
User interact with the panel thanks to a rod that is attached to the display.
By rotating the display, users activate controls by crossing them with the rod.
Attaching the panel and the rod to the display allows it to be operated independently from the display's translation.
Here, we show how a slider on the panel can be used to control a zoom factor
while the scene is being explored by display translations.
Now, we show the exploration of the commands of a two-levels radial menu.
The leaves of the menu are only activated after a short delay.
We ran a qualitative user experiment with eight participants.
Without explanations, all participants discovered and understood all the interactions in less than three minutes.
Please refer to the paper for details.