Combining Redirection with Common Game Elements

Mathieu Lutfallah

∗ a

, Joel Hauser

∗

, Edoardo Negri

∗

, Andreas Kunz

{mlutfallah, kunz}@ethz.ch, {johauser, enegri}@student.ethz.ch

Keywords:

Redirection, Redirected Walking, Locomotion, Natural Walking, Distractors.

Abstract:

This study explores how integrating common game elements with redirection techniques inﬂuence user per-

ception and whether they can be adjusted to induce higher gains and more movement. We tested four game

elements: user interface spawning position, spawning of collectibles, interactions with non-player characters,

and interactions with enemies. These elements were combined with rotational gains. Additionally, we ex-

amined the effects of terrains in combination with translational gains, as well as a new redirection technique

inspired by slipping. Our ﬁndings indicate that combining game elements with rotational gains led to increased

movement, providing greater opportunities for redirection while masking the manipulation. With proper ad-

justments, this approach can remain unobtrusive to the user experience. However, special terrains resulted in

a similar detection of manipulation for both, the slipping method and the translational gains. This work paves

the way for future research on integrating these game elements with rotational and translational gains.

1 INTRODUCTION

Virtual reality (VR) games is becoming increasingly

popular, with VR game revenue expected to reach

$3.2 billion in 2024

. Natural walking where the

player’s movement is mapped 1:1 to the virtual envi-

ronment (VE), consistently emerges as the best loco-

motion technique to navigate VEs as shown by Usoh

et al. (1999). However, this technique requires the

physical space to match the size of the virtual world,

which is often not the case. Therefore, redirection

techniques have been developed to steer the user’s

path towards navigable areas in the physical space.

(Suma et al., 2012) looked into creating a taxonomy

for these techniques. Among the criteria used to clas-

sify them were subtle or overt. Subtle ones are not

perceived by the user, while overt techniques are no-

ticed by the user and might lead to a break in pres-

ence. Subtle techniques are often favored for that

reason. Redirected Walking (RDW) is a subtle tech-

nique, allowing the manipulation of the mapping be-

tween movements in the physical and virtual worlds.

This is used to steer the user away from boundaries

based on various gains, which were formally deﬁned

in the work of (Steinicke et al., 2010). Among these

gains, rotational gains scale the rotation of the physi-

https://orcid.org/0000-0001-7863-8889

https://orcid.org/0000-0002-6495-4327

∗

These authors contributed equally to this work.

cal world when mapped to the virtual camera. On the

other hand, translational gains allow for scaling the

distance traveled, either slowing down or speeding up

the user’s movement. Other types of gain has also

been presented, pushing for newer ideas e.g, bending

gains that lead the user to walk on a curve in the real

space, as presented by (Langbehn et al., 2017), and

redirection during non-forward steps, as developed by

(Cho et al., 2021).

Mismatches between the mapping of physical

movements and their virtual counterparts are limited

by thresholds where users begin to notice the dif-

ferences. Extensive research has been conducted to

determine these thresholds: (Steinicke et al., 2010;

Williams and Peck, 2019; Kruse et al., 2018). While

these thresholds are inﬂuenced by various factors

such as user characteristics, adaptation over time, the

features of the head-mounted display, and the type of

environment, they still restrict the possibility of un-

limited walking in inﬁnitely large virtual spaces. To

address this, researchers have attempted to combine

gains with speciﬁc aspects of the environment to in-

duce movement, allowing for greater alterations in

the mapping (higher thresholds) or masking the ma-

nipulations. The elements incorporated to achieve

these goals are often referred to as distractors, which

are features that capture the user’s attention, forc-

ing movement or reducing their ability to notice the

manipulations. This was initially explored by (Peck

Lutfallah, M., Hauser, J., Negri, E. and Kunz, A.

Combining Redirection with Common Game Elements.

DOI: 10.5220/0013142400003912

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 20th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISIGRAPP 2025) - Volume 1: GRAPP, HUCAPP

and IVAPP, pages 569-576

ISBN: 978-989-758-728-3; ISSN: 2184-4321

569

et al., 2009), where different types of distractors were

tested highlighting that when integrated into the VE

context were better perceived by users.

In this work, we explore the combination of the

most common game elements with rotational and

translational gains. The goal of this combination is

both to mask the mismatch that occurs and to encour-

age more user movement, enabling the application

of redirection techniques. After an analysis of pop-

ular games, we identiﬁed ﬁve aspects that can be used

for redirection: user interface (UI) elements spawned

during the gameplay, spawning of collectibles, inter-

actions with non-playing characters (NPCs) and en-

emies, and terrains. An illustration of the modiﬁca-

tions to these elements is shown in Figure 1. The ﬁrst

four mentioned elements UI, collectibles, NPC, and

enemy interactions, were combined with rotational

gains, while terrains were paired with translational

gains. We examined how applying rotational gains

during interactions inﬂuence the redirection percep-

tion—either by forcing the user to walk around an

NPC to engage with it or during ﬁghting enemies. For

collectible objects, we explored how dropping them

away from the user in optimized locations might en-

courage more user rotation. For the UI, we investi-

gated how spawning it at a different angle from the

user, rather than directly in front, could impact the

user’s experience.

The concept of terrain effects originates from real-

world. (Leicht and Crowther, 2007) demonstrated

that walking on dry beach sand reduces speed and

increases the number of steps compared to walking

on concrete or grass. Ice further complicates locomo-

tion by introducing slipping. Most translational gain

experiments have focused on virtual standard terrains

that do not impede movement in physical space. To

address this gap, we propose two approaches: induc-

ing slipping at the end of a walk and applying contin-

uous slowing gains during walking. Utilizing terrains

where users naturally walk slower or experience slip-

ping could enhance the effectiveness and realism of

redirection techniques.

This work presents the user studies conducted to

evaluate perceptions of these modiﬁcations and assess

whether these elements can effectively mask the ma-

nipulation. The remainder of this paper is structured

as follows: First, we will present related work on gain

threshold determination and the use of distractors in

redirection methods. This will be followed by a de-

scription of the VEs developed for the study and the

study procedure. Finally, we will present the results

from the user studies, followed by a brief conclusion.

VR Game Revenues Report, accessed on 14.01.2024

2 BACKGROUND

(Steinicke et al., 2010) showed that rotations can be

sped up by 49% or slowed down by 20% without the

player noticing, and translational movements can be

up-scaled by 26% and down-scaled by 14% without

be noticed by the user. A study by (Kim et al., 2022)

analyzed how the size of a room impacts the thresh-

olds for translational gains. They found that trans-

lational gains are more noticeable in smaller rooms

than in larger ones. (Kruse et al., 2018) investigated

the impact of showing the user’s feet and the number

of visual cues in the space on sensitivity to transla-

tional gains. Additionally, (Williams and Peck, 2019)

explored thresholds in relation to user characteristics,

such as gender, and hardware characteristics, such as

ﬁeld of view (FOV).

Peck et al. worked with distractors in several stud-

ies by combining them with resets, which are fail-safe

mechanisms used when a collision is imminent, re-

quiring the user to stop navigation and reorient them-

selves. First, (Peck et al., 2009) demonstrated that the

more integrated a distractor is with the overall con-

text of the VE, the more it is liked by users and the

less noticeable the reorientation becomes. (Chen and

Fuchs, 2017) followed up by presenting S2C with re-

sets based on interactive distractors. In this setup, a

dragon appears and needs to be shot while the gain

is applied, rotating the user to the center. Similarly,

(Cools and Simeone, 2019) investigated the interac-

tivity between distractors and their effects on user per-

formance and behavior. They tested three continuous

reorientation-based resets and one based on discrete

reorientation. The work showed that using distrac-

tors led to less breaks in presence and was preferred

by users. Another study by (Sra et al., 2018) intro-

duced the concept of coupling game elements that

typically cause intentional blindness reduction with

redirection. These aspects were shown to enhance

presence, reduce dizziness, and improve the unnotice-

ability of the reorientation.

Other researchers investigated new thresholds

when distractors are combined with other elements,

rather than solely studying their effects on user ex-

perience and perception, as seen in the previous sec-

tion. (Schmelter et al., 2021) combined discrete rota-

tion jumps with common actions performed in games,

and identiﬁed the extent of rotation that can be ap-

plied while remaining unnoticed. (Williams and Peck,

2019) examined the effects of a deer walking in front

of the user and determined the associated thresholds.

(Lutfallah et al., 2024) explored how the established

thresholds for translational gains could be pushed

when combined with a shooting task while walking.

HUCAPP 2025 - 9th International Conference on Human Computer Interaction Theory and Applications

570

Figure 1: Illustrations of the different game elements combined with either rotational or translational gains. Images (a) to (d)

show the user experiencing rotational gains, while image (e) demonstrates the user experiencing translational gains. In (a),

the user must walk to the yellow area to interact with the non-player character. In (b), the user interacts with enemies. In (c),

the user rotates to collect an item. In (d), the user interacts with a menu spanning to their left, also forcing rotation. Image (e)

highlights the user walking straight, where the terrain may either slow the user down (sand) or cause slipping (ice).

3 PROPOSED TECHNIQUES AND

IMPLEMENTATION

We investigate ﬁve different game elements, each in-

cluding one modiﬁcation or combination, except for

terrain, where two possibilities emerged: either slow-

ing terrains or slippery terrains. We decided to divide

the experiments into two user studies to keep them

short and avoid overwhelming the participants. The

user studies were divided based on the type of gain

applied. Thus, the two terrain aspects were tested in

one user study which will be labeled as translational

modiﬁcation study (TMS), while the other four ele-

ments combined with rotational gains were tested in a

separate user study that will be referred to as rotation

modiﬁcation study (RMS).

The two environments were built using the Unity

3D game engine. As a foundation for the games,

OpenRDW by (Li et al., 2021) was used, which pro-

vided implementations of rotational and translational

gains. The HTC VIVE Focus 3 was used as head-

mounted display (HMD), offering a display resolution

of 2448p x 2448p per eye and a refresh rate of 90Hz.

The game run on a PC with an Intel Core i9-12900KF

processor and an Nvidia GeForce RTX 3080Ti graph-

ics card, and was streamed to the HMD.

3.1 Virtual Environment for TMS

In this study, we investigated the effect of terrain in

combination with translational gains. Our aim was to

explore how different terrain types, which challenge

walking ability in real-world environments, might in-

ﬂuence user experience in a virtual setting when com-

bined with redirection. For this purpose, we build

two virtual environments of for each of the two ter-

rains: the ﬁrst had shallow water that typically slows

the user, and another simulating ice, where slipping

is a factor. The goal was for users to experience the

same redirection with both modiﬁed terrain (ice or

water) and normal terrain. Based on this, the design

choice was to create a long, rectangular VE where the

user walks straight toward a checkpoint indicated by

a glowing sphere. The walkable area is 15 ×3 meters,

bordered by walls. On the forward path, the user ex-

periences one type of terrain, and on the return path,

the other terrain; for example, the user might walk

through water, experiencing a slowing effect, and on

the way back, walks on normal ground experienc-

ing the same slowing gain. The different terrains are

shown in Figure 2. An avatar representing the user’s

body, taken from the FinalIK asset, was shown and

adjusted to match the user’s dimensions, enhancing

bodily self-immersion. Additionally, corresponding

footstep sounds were added to simulate steps on ei-

ther water or ice.

In the water scene, a texture is applied to the walls

and ﬂoor such that they resemble an outside pool, and

also a layer of water, with a height of 0.4m, is applied

above the ﬂoor level. In the ice scene that was used

to test the slipping mechanism, we had two types of

grounds: the normal one as well as the one where an

ice texture was applied. The slipping mechanism is

triggered whenever the user’s speed falls below a cer-

tain threshold. The user’s position gradually shifts in

the direction of movement, with the push effect fad-

ing over time. This is achieved using Unity’s Lerp

function, with a decay factor controlling the diminish-

ing effect of the slip. The threshold for triggering the

slipping, as well as the various slipping values tested,

were empirically determined based on a preliminary

small user study.

Combining Redirection with Common Game Elements

571

(a) (b)

Figure 2: The virtual environment depicted shows the user

walking on water terrain in (a), ice terrain in (c), and normal

pavement on the return path in (b) and (d).

3.2 Virtual Environment for RMS

In this study, rotational gains were combined with

four game elements. The game is set in a dungeon

composed of three adjacent rooms, each measuring

4m × 4m. In each room, one element (except the user

interface) was utilized. Figure 3 shows screenshots of

the rooms containing the game elements, along with

a screenshot of the inventory UI. Background music

was played throughout the game to enhance player

immersion and mask external noises not related to the

game. The sound was non-spatial, meaning it did not

originate from a speciﬁc location in the dungeon. The

four rooms did not ﬁt within the physical space, which

had dimensions of 10 × 6 meters. However, interact-

ing with each element in the room led to a continuous

reorientation until a 90

◦

rotation between the physical

space and the VE was reached. This was followed by

an additional 90

◦

continuous reorientation when the

participant interacted with the door, resulting in a total

reorientation of 180

◦

in each room. This ensured that

the second room always ﬁts within the available phys-

ical space. Additionally, 2:1 resets following the im-

plementation in the OpenRDW library were allowed

in case the system failed to reorient the user properly.

The interaction with the UI was repeated three

times, as the player had to collect three keys in each

room. The keys were picked up by hovering over

them and pressing a button, which caused them to

disappear and be added to the inventory. When all

keys in a room were collected, the inventory could be

opened by pressing the trigger button on the left con-

troller. The inventory then appeared at a 90

◦

offset to

the left of the player’s current facing direction. It dis-

played three pictures of the keys, which also served as

buttons that the player could hover over and press the

trigger button to activate a key. The inventory would

then close, and a green sphere would appear on the

right side of the door, encouraging the player to turn

and look at it, signaling successful key usage. The

player repeated this process three times until the door

opened. In this work, the UI referred to an inventory

list however this can be generalized to any UI needed

in a game such as a menu or map.

The second element investigated was the spawn-

ing of collectables that would force the user to rotate

rather than spawning directly in front of the player.

For this, a chest was used where the player had to

hold their hands over it and press the trigger button

on the right controller. The key then spawned above

the chest with a force applied to it, propelling it ap-

proximately 1.5m in a certain direction. To pick up

the key, the player had to walk and rotate. This pro-

cess was repeated three times to obtain the three keys,

with the ﬁrst and third keys ﬂying to the left and the

second key ﬂying to the right.

The third element tested was NPC interaction.

The goal was to force the user to walk around the

NPC, represented by a person, to initiate a conver-

sation. The NPCs were placed in the opposite direc-

tion from which the player entered the room, com-

pelling rotation. Interaction was possible only when

the player stood in front of the NPC, marked by a

white circle on the ﬂoor. When the player stepped into

the circle, it turned green, indicating correct position-

ing. Pressing the trigger button on the right controller

then caused the NPC to drop a key.

Fighting with a sword while applying rotational

gains was also examined. The player fought three

skeletons using a sword. The sword was placed in

the middle of the room, surrounded by the skeletons.

This required the player to rotate to ﬁght the skele-

tons, which did not move toward the player before the

sword was picked up. To pick up the sword, the player

had to move their hand close to it and then press and

hold the trigger button on the right controller. If the

sword touched a skeleton, the skeleton disappeared

and dropped a key.

For all the game elements tested, the rotational

gain values were the same and were applied only

when the user was interacting with the proposed el-

ement. As a result, walking between the rooms was

free from redirection. Additionally, whenever a reori-

entation of 90

◦

happened for a speciﬁc element the

rotational gains were set to 0. A rotational gain value

lower than the one proposed by (Steinicke et al., 2010)

was used because a preliminary user study showed

that users tend to notice redirection more in smaller

rooms with a high number of object, consistent with

the work of (Kim et al., 2022). Therefore, gains of

31% and −12% were applied, depending on whether

the rotation was accelerated in the direction of head

movement or in the opposite direction.

HUCAPP 2025 - 9th International Conference on Human Computer Interaction Theory and Applications

572

(a) (b)

Figure 3: Screenshots from the virtual environment show-

ing different rooms and their respective game elements. In

(a), the inventory UI is displayed, where the user can select

keys to open the door. In (b), the chest that spawns the key

is shown. In (c) and (d), non-player characters (NPCs) are

displayed with the interaction circle in front of them, and in

(d), the enemy skeletons and the sword are visible.

4 USER STUDY

For both user studies, participants were recruited from

the university staff and students. All participants had

normal or corrected-to-normal vision. The RMS in-

cluded 19 participants (16 identiﬁed as male while

3 as female), while the TMS had 22 participants (14

identifed as male, 7 as female and 1 selected “Other”

option). Some participants took part in both studies,

since the studies were conducted a month apart. The

mean age of participants was 24.58 ± 2.16 years for

the RMS and 23.5 ± 2.94 years for the TMS.

The procedure followed by users was similar for

both experiments. First, participants signed a consent

form. Then, they completed a demographics ques-

tionnaire, which asked about their age, gender, and

prior VR and gaming experience, followed by the

Simulator Sickness Questionnaire (SSQ). Participants

were given instructions on how to complete the tasks

and interact with the elements they would encounter.

In both experiments, participants completed an in-

troductory scene to familiarize themselves with the

gameplay mechanics and interactions. In the TMS,

the introductory scene allowed participants to walk,

while in the RMS, they were shown a room with the

four elements and were required to interact with each

element. In both introductory scenes, no gains were

applied. After completing the tasks in each study, par-

ticipants ﬁlled out the SSQ again and answered sev-

eral customized questions.

For both studies, counterbalancing of experiments

was employed. For the TMS study, half of the par-

ticipants started with the ice experiment and the other

half started with the water experiment. Additionally,

half of the participants experienced the normal pave-

ment terrain ﬁrst, followed by the special terrain. This

was done to prevent any bias from the order of the ex-

periments. We tested multiple gains to determine if

different levels of redirection would affect user per-

ception. This procedure was the same for both the

water and ice scenes. In the water scene, we adjusted

the slowing translational gain, while in the ice scene,

we modiﬁed the slipperiness. The participants were

also informed that a speed manipulation would be ap-

plied during the walk, with the manipulation changing

after every second checkpoint. There are ﬁve slow-

ing translational gains that the player is exposed to

in the water scene: 1, 0.9, 0.8, 0.7, 0.6. Every sec-

ond checkpoint, the user needs to select one of the

terrains to answer the question “On which terrain did

you feel slower?”. To answer this question, the user is

informed that the answer will appear as text on both

hands, and they will need to press the correspond-

ing buttons on the controller. This approach follows

the Two-Alternative Forced Choice (2AFC) method

used in previous works as the ones of Steinicke et al.

(2010). For the ice scene, the perception is tested

across different slipperiness levels, ranging from no

slip (NS), low slip (LS), medium slip (MS), high slip

(HS), to very high slip (VHS). Every second check-

point, the user need to select one of the two terrains

to answer the question “On which terrain did you feel

less slippery?”. Again, the answers were selected by

pressing a corresponding button.

For the RMS, participants played two rounds of

the game, with each round consisting of the same

three rooms presented in a different but counterbal-

anced order. Participants had to collect three keys in

each room and use them to progress to the next one.

In the chest room, participants spawned the three keys

from the chest and collected them. In another room,

they collected three keys from three bandits, and in

the third room, they had to kill three skeletons, each

of which dropped a key.

5 RESULTS AND DISCUSSION

For the TMS and RMS, the mean difference in pre-

and post-SSQ questionnaires was 0.51 ± 22.98 and

14.34 ± 18.41, respectively. Two participants had a

difference greater than 40 for RMS, speciﬁcally 59.8

and 52.36, while one participant showed a difference

of 56.2 for TMS. This suggests that the RMS induced

more cybersickness than the TMS, and this difference

was statistically signiﬁcant based on a Mann-Whitney

Combining Redirection with Common Game Elements

573

Figure 4: The number of responses indicating that the ma-

nipulation felt stronger for each corresponding gain, com-

paring the water and the normal pavement conditions.

U test. It should be noted that participants spent a

longer time in VR during the RMS experiment.. How-

ever, since none of the participants reported feeling

symptoms or mentioned that this hindered the experi-

ment, all participants were included in the results.

5.1 Results for the TMS

In this study, the goal was to determine whether par-

ticipants would perceive the manipulation more on

normal pavement or on water and ice pavement. To

investigate this, a 2AFC question was asked when the

same manipulation was applied to both pavements.

For the water experiment, 58.1% of participants

reported that they felt the slowing effect more strongly

when walking in shallow water. A binomial test

with k = 0.5 was conducted to assess whether par-

ticipants genuinely perceived a difference. The result

(p > 0.05) suggests that the null hypothesis—that the

answers were given randomly—cannot be rejected.

Further investigations were conducted to examine the

correlation between the gain applied and the partici-

pants’ perception. The distribution of responses that

the terrain with water had more slowing compared to

the gain applied is shown in Figure 4. For the ini-

tial condition where no gain was applied, 81% of par-

ticipants reported that the manipulation felt stronger

on the water terrain. This suggests that participants

expect to move more slowly in water, even when no

manipulation is present. The percentage of responses

indicating that the manipulation was stronger in water

decreased as the gain increased, but remained equal to

or above 50%.

In the ice experiment, 50.9% of participants re-

ported feeling the manipulation more on the normal

terrain than on the ice terrain. We further investigated

participants’ perception across different slipperiness

levels, ranging from NS to VHS (see Figure 5). The

distribution of responses was nearly equal, suggesting

that participants were answering randomly. This ob-

servation was further supported by the binomial test,

where we obtained p > 0.05 for all conditions.

Figure 5: The number of responses indicating that the ma-

nipulation felt stronger for each corresponding slipperiness,

comparing the ice and the normal pavement conditions.

Additionally, both experiments were rated as

highly immersive on a scale of 0 (low immersion) to

5 (very immersive). The water experiment was rated

at 4.09 ± 0.86, and the ice experiment at 4.18 ± 0.85.

Based on the Shapiro-Wilk test, the distributions were

not normal; therefore they were compared using the

Wilcoxon test, which revealed no statistically sig-

niﬁcant difference. Furthermore, participants rated

whether they felt more immersed when walking on

the normal terrain versus the ice, as well as between

water and normal terrain. A score of 0 indicated

greater immersion in the normal terrain, while 5 in-

dicated greater immersion in the special terrain. The

respective scores were 3.4 ± 1.1 for the ice scene and

3.23 ± 1.0 for the water scene, showing that in both

cases, participants felt more immersed when walk-

ing on the special terrains. Finally, participants rated

whether they felt the water and ice masked the manip-

ulation, compared to the normal pavement, on a scale

from 0 to 5. The water and ice scenes received a score

of 3.27 ± 1.1 and 3.4 ± 1.1, respectively.

5.2 Results for the RMS

For the user interface part, 8 questions were asked to

investigate the user perception of the rotational gain

and the modiﬁcation of the UI’s spawn position. A

total of 42.11% of participants reported having dif-

ﬁculty ﬁnding the inventory after opening it by an-

swering “Yes.” Responses to ordinal questions (0 =

Do not agree, 5 = Agree) indicated that the inven-

tory’s use was not very intuitive for all participants

(µ = 3.53 ± 0.88), that the 90° offset of the inven-

tory disrupted the game ﬂow (µ = 3.16 ± 1.14), and

that the offset was also considered annoying (µ =

3.37 ± 1.13). Participants were further asked what

degree of offset would be appropriate to avoid dis-

rupting the game ﬂow or causing annoyance, and an

average value of 47.03 ± 17.81

◦

was reported. To

determine whether participants noticed the rotational

gains, a similar approach to (Suma et al., 2011) was

used, where decoy questions were included alongside

HUCAPP 2025 - 9th International Conference on Human Computer Interaction Theory and Applications

574

those directly referencing the modiﬁcation. In re-

sponse to the relevant question about rotational gains,

36.84% of participants reported noticing this manip-

ulation. The decoy questions, “Did the room get big-

ger or smaller while using the inventory?” and “Did

it feel like you were getting bigger or smaller while

using the inventory?” were both answered “No” by

all 19 participants, indicating no guessing occurred.

For close combat, ordinal questions (0 = Do

not agree, 5 = Agree) indicated that participants felt

highly immersed during the ﬁght (µ = 3.84 ± 1.42),

but the ﬁght itself did not feel very realistic (µ =

2.34 ± 2.23). This was mainly due to the simplistic

mechanic where merely touching the enemy resulted

in death, without a health system that would allow the

user to die if attacked. Only 15.79% of participants

felt that their rotations were sped up or slowed down

during the ﬁght. The decoy question, “Did you feel

like you were getting smaller or bigger while ﬁghting

the skeletons?” was answered “Yes” by only 5.26%

of participants, indicating no guessing occurred. Ad-

ditionally, 21.05% of participants felt like the world

was rotating around them.

For the chest interaction, two decoy questions

were asked. “Did you feel like your forward move-

ment was sped up or slowed down while picking up

the keys?” was answered “Yes” by 5.26% of par-

ticipants, and “Did objects (keys or chest) on the

ﬂoor move by themselves?” was answered “Yes” by

10.53%. The rotational gains were noticed by 31.58%

of participants based on the corresponding question.

Participants also answered ordinal questions regard-

ing the chest interaction. When asked to rate the ease

of spotting the keys, where 1 meant “Easy” and 5

meant “Hard,” the score was 2.11 ± 0.72. Regard-

ing whether the keys ﬂew too far from the chest, thus

interrupting the game ﬂow (1 = Do not agree, 5 =

Agree), the score was 2.53 ± 0.99. For the question

of whether participants would have preferred the keys

to be dropped directly in front of them (1 = Agree, 5

= Do not agree), a score of 3.32 ± 1.45 was recorded.

For the NPC interaction, the decoy question,

“Did it feel like your forward movement was sped up

or slowed down while walking in the room with the

bandits?” was answered with “Yes” by only 5.26% of

participants, and 36.84% of participants noticed the

rotational gain. The question on whether NPCs not

facing the user was disruptive scored 1.79 ± 0.95 (0

= not disruptive, 5 = very disruptive). The question,

“Usually in games, NPCs like the bandits can be inter-

acted with from any side. Do you think that the cur-

rent implementation is better?” was answered “Yes”

by 57.9%, “No” by 10.53%, and “It does not matter”

by 31.57%.

5.3 Discussion

Regarding the game elements combined with rota-

tional gains, all of them led to less than 50% notic-

ing the manipulation applied. Fighting with the ene-

mies resulted in better masking of the manipulation,

with 15.79% noticing it, while for the other elements,

the rate ranged between 31% and 37%. This supports

the hypothesis that the more engaged a user is, the

less likely they are to detect the manipulation. For

speciﬁc elements, the UI results indicate that the cho-

sen shift of 90

◦

was too large, with almost half of the

participants having troubles to locate. However, even

with such a large spawning angle shift from the user’s

front, the negative impact was relatively low. Know-

ing that the user had to select objects three times, it

can be assumed that if the user only had to perform the

selection once, discomfort could be reduced. For the

key drop out of the chest, most participants stated that

the key’s propulsion from the chest was still easy to

spot, and the ﬂow disruption was rated neutrally, indi-

cating that the modiﬁcation was acceptable. The NPC

interaction modiﬁcation was rated as the least disrup-

tive (1.79), and the majority of participants (57.9%)

afﬁrmed that they preferred having the limited inter-

action area over being able to interact with NPCs from

the other side. This suggests that this element could

be used to induce rotation, with NPCs being dynami-

cally placed in the space depending on the reorienta-

tion needed.

The results from the terrain modiﬁcation exper-

iment show that the type of terrain did not signiﬁ-

cantly affect the detection of manipulation for either

the translational gain or the slipperiness effect, except

in the base case of translational gains, where 80%

of participants stated that the gain felt higher on the

water terrain. This was reﬂected by approximately

50% consistently rating the special terrain as having

more manipulation. This ﬁnding contradicts our ini-

tial hypothesis that participants, expecting to move

more slowly, would perceive less manipulation. Sev-

eral factors could explain this, such as the absence of

haptics. Despite that, the terrains were beneﬁcial in

terms of immersion, as participants rated the special

terrains as more immersive than the normal ones.

5.4 Limitation

Several limitations may have affected the results of

the two user studies. First, the participants were pri-

marily male students, which could have biased the

results. Regarding the rotational gain-based study,

only a single value for rotation was tested to keep

the experiment short. However, testing multiple val-

Combining Redirection with Common Game Elements

575

ues for rotational gains, as well as different angles for

UI shifts and distances for key drops from the chest,

would have helped identify optimal values. Nonethe-

less, this work primarily aims to pave the way for

future element-speciﬁc user studies. In the slipperi-

ness experiment, the slip effect was calculated using

Unity’s lerping function rather than a physics-based

method, which could be improved. Additionally, in

both the water and ice terrain experiments, haptic

feedback could be incorporated to enhance immer-

sion. Furthermore, full-body tracking was not used

to track participants’ feet and sync the sound of foot-

steps, potentially causing a discrepancy between the

timing of steps and the triggered sound.

6 CONCLUSION

This work provides valuable insights into how game

elements can be integrated with rotational and transla-

tional gains to improve VR navigation while reducing

the noticeability of manipulations. The study shows

that game elements like NPC interactions and enemy

combat can effectively mask rotational gains. How-

ever, terrain manipulations (especially ice and water)

require further reﬁnement, as users detected the same

level of manipulation as on normal pavement. Over-

all, this work contributes to enhancing natural walk-

ing in VR, but further research is needed to determine

the optimal values for UI position changes and col-

lectible drop distances to minimize discomfort. Addi-

tionally, more exploration of terrains is necessary, as

users rated positively for immersion.

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