This project aims to design a permanent, immersive indoor sensory environment that mimics the calming properties of the outdoors to provide a non-verbal, four-year-old child with a secure, accessible space for emotional regulation and hands-on exploration.
The client is a four-year-old child with a Level 3 Autism diagnosis who is non-verbal and primarily engages with the world through movement and hands-on exploration. He prefers being outdoors and lacks interest in typical toy play, instead he enjoys playing with natural materials like river rocks or sensory beans. Because he relies on these specific environmental inputs for emotional regulation, he experiences significant dysregulation when outdoor access is unavailable. Currently, the primary indoor solution for his need to hide away and reset is a large blackout tent that is difficult and time-consuming for the family to assemble. This existing temporary setup fails to provide a permanent, accessible, and immersive outlet that satisfies his sensory input needs, such as his interest in lighting, rhythmic sounds, and cozy enclosed spaces.
He has physical requirements for soft, supportive environments due to low muscle tone and challenges with balance and strength. There is a critical need for a specialized, permanent indoor space that mimics the calming properties of the outdoors while providing the “cozy” enclosed security he craves.
Structure and Materials:
Lighting and Auditory features:
Communication Interface:
Structure and Material:
Communication Interface:
Our project design is a safe, cushioned structure with a “cave” with easily controllable lighting and music.
Modular playplace featuring an elevated platform, a ramp for easy access, stairs to develop motor skills, handles to develop grabbing motions, an interior room for comfort and soothing, and a drum mounted into the wall for sensory stimulation.
Sketch of indoor playset featuring a top play area and a bottom enclosed sensory room. The playset includes stairs that lead to a play area with outdoor sensory simulation toys and drums on the back wall, with a slide to get down. The enclosed sensory room on the bottom is a space for decompressing and comfort.
This sensory-focused play structure features a raised platform equipped with an interactive sensory board and a built-in drum for stimulation. A set of steps provides a stable climb to the top, while a slide and safety railings offer a secure and engaging way to descend. Beneath the platform, a secluded hideaway enclosed by blackout curtains creates a dedicated low-sensory sanctuary for the child to decompress.
| Manufacturability | Price | Modularity | Cleanliness | Engagement | Sum | |
| Concept 1-Tyler | 1 | 1 | 2 | 2 | 2 | 8 |
| Concept 2-Penny | 2 | 3 | 1 | 1 | 1 | 8 |
| Concept 3-Emma | 3 | 2 | 3 | 3 | 3 | 14 |
Since there are two groups working on this project, we collaborated with the parents of the child as well as the other group to decide on a final design, taking all aspects of proposed designs into account.
After collaborating with team 13b, a combination of the two designs was selected.
The concept art pictured to the left is an initial rendering of the overall look and features of the design.
In the top left corner of the image, color swatches are included to define the color palette.
Structure:
The structure is a trapezoid with a ramp connected to the back wall. Each of the exterior walls will be painted to reflect views of nature. The top of the structure will also have a standing area. This area will include a railing comprised of both wood and rope to add to the theme.
Ramp:
The ramp will have a gradual slope with a small landing at the top. This landing will be where the tree attaches to the ramp.
Tree:
The tree will include nature windows that the child can open to reveal different objects.
“Cuddle Box”:
The box will be fully dark with a fiber optic star field created on the ceiling. This box will be accessed through the two openings in the front of the structure
Overall:
The structure will be primed with shellac primer and painted with interior acrylic paint. This should allow for easy cleaning and durability.
All walking surfaces will be covered in turf.
To ensure the top platform of the cuddle box is safe and rigid, we ran a preliminary structural analysis using the Express Simulation features in SolidWorks. The primary goal of this simulation was to generate qualitative visual feedback to compare framing approaches and observe load distribution, rather than to extract precise quantitative measurements.
For this study, a downward load of 900 N (approximately 202 lb) was applied to the center of the platform to simulate the weight of a person. The first test evaluated the platform as a single, unsupported sheet of wood spanning the upper frame. As seen in the first image, applying this load to an unbraced surface results in a large red concentration in the center. This color mapping indicates severe stress and potential deflection, confirming that relying on an unsupported sheet would not provide a stable or safe surface for use.
The second test updated the model to include underlying supports and cross members, mirroring standard deck framing practices. Under the same 900 N load, the results show a dramatic improvement. The high-stress red zones are completely eliminated, replaced by a predominantly blue map that indicates the force is safely and evenly distributed across the structural bracing. This visual analysis confirms that utilizing a traditional joist structure beneath the platform will provide the necessary strength and safety for the final product.
To account for the final logistics of the project, a detailed weight analysis was performed to evaluate the requirements for transporting the completed design from the college shop to the client’s property. While the structural simulations confirmed the integrity of the platform, this analysis focused on the physical reality of moving the mass and volume of the finished assembly.
Based on the project’s bill of materials, the total weight of the design components is 1,114.8 lbs. Since the transport phase involves moving the design from the fabrication site to its permanent home, this half-ton payload represents a significant logistical factor.
The weight is distributed across several major sub-assemblies, including the structural OSB frame, the tree-themed plywood accents, and the integrated plinko board. While the 1,115 lb total is well within the payload capacity of a standard pickup truck or utility trailer, the primary challenge of this transport lies in the dimensions of the components. The analysis shows that the bulk of the weight is tied to 8-foot and 10-foot elements—specifically the long foam cushions, the OSB sheathing, and the 12-foot turf sections.
Quantifying these weights allows us to plan for a safe and efficient delivery, ensuring that the transport vehicle is balanced and that the modular sections are manageable for the final installation team. By documenting the total mass of the structure, we can guarantee that the move from the college property to the client is executed without exceeding vehicle limits or risking damage to the finished finishes and hardware.
To complement the visual results from the SolidWorks simulation, a formal Mechanics of Materials (MoM) analysis was performed to mathematically determine the maximum safe unsupported span for the 7/16-inch OSB platform. By idealizing a 12-inch wide section of the wood as a simply supported beam, we were able to evaluate the design against its two primary failure modes: material rupture (flexural stress) and excessive sagging (deflection).
For this calculation, a design load of 200 lbs was applied as a concentrated point load at the center of the span. This represents the worst-case scenario of a single user’s weight being focused on a small area. Using a standard modulus of elasticity (E) of 700,000 psi and an allowable bending stress (F_b) of 600 psi, the analysis yielded the following results:
Flexural Stress Limit (L_stress): The material reaches its safe bending limit at a span of 4.59 inches. Spans wider than this risk structural failure of the wood fibers under a 200 lb load.
Deflection Limit (L_deflection): To meet the L/360 industry standard for floor stiffness (preventing a “spongy” feel), the span is limited to 6.25 inches.
Conclusion
The analysis confirms that the governing limit is 4.59 inches. Because the internal strength of 7/16″ OSB cannot safely support a concentrated 200 lb load over a significant distance, the inclusion of the structural joists seen in the SolidWorks simulation is mandatory. This quantitative data justifies the use of a closely spaced framing system to ensure the platform remains both safe and rigid for the client.
For step-by-step calculations, see the attached PDF.
Reference document: https://awc.org/resource-hub/span-table-tutorial/
The overall fabrication process included many stages, steps, and sub-processes, some of which occurred simultaneously. The initial stage focused on the main structure and ramp. While this was happening, other group members started the fabrication of the additional elements, which would be added to the overall structure. After the main framework was completed, external and internal boards were affixed to the structure to allow for the internal “cave” hidey-hole.
Moving forward, the group’s key focus was to complete the aesthetic portion of the project, adding all of the details and interactive elements. Turf was added to all walking surfaces, and all external paneling was painted to give an outdoors-like look & feel.
Since the project was built off-site and must be transported, all external paneling remained separate, and only internal panels remained on the framework for transport. All panels were painted before arriving onsite for assembly to allow the clients to immediately access the structure upon completion of assembly.
Testing performed for this structure was quite basic, with weight-bearing tests:
Additionally, practical testing was performed by the intended user once assembly was complete. See the video below for details: https://youtu.be/6OvLsFMWylY
The structure is child-safe in all intended use cases. It is important for the child to always have adult supervision just in case anything happens. The structure has several safety features, including padding on the inside, rope and railing on the top, sanded edges, and wall supports on both sides of the ramp. If the turf were to get wet, it is important to clean and dry the surface before use, since it could make the turf slippery. To ensure safe usage, the child should:
Our structure is designed to accompany one adult with a child. It has several elements to it, making it interactive for the child and parents to play together! So, have fun and be safe!
We designed and fabricated a permanent, immersive indoor sensory environment for a four-year-old, non-verbal child with Level 3 autism. Because the client relies heavily on outdoor environments for emotional regulation and experiences dysregulation when outdoor access is unavailable, our goal was to bring the calming properties of nature indoors. The final design integrated a multi-level play structure with a specialized “Cuddle Box”—a padded, cave-like pod featuring a fiber-optic Ursa Minor constellation ceiling and adjustable lighting. The exterior of the structure included a ramp, a lookout deck, turf walking surfaces, and a tree with interactive nature windows to encourage hands-on exploration.
To ensure the structure was completely safe for use, we ran rigorous engineering analyses. Using SolidWorks Express Simulations and a formal Mechanics of Materials analysis, we determined that an unsupported 7/16-inch OSB platform would fail under a 200 lb concentrated load at a span of 4.59 inches. This data allowed us to optimize a traditional joist support system beneath the platform to safely distribute up to 900 N of force.
This project provided an incredible real-world perspective on what it means to be an engineer, specifically highlighting the value of collaboration and logistical planning. Merging teams 13a and 13b presented a unique challenge, requiring us to navigate the dynamics of combining eight individuals with distinctly different mindsets and design approaches. Learning to manage these differing perspectives was a critical part of the process, and constructively working through those differences ultimately allowed us to pull the strongest elements from multiple concepts into one unified, highly personalized solution.
Another significant challenge was the sheer scale of the fabrication and transport phase. As detailed in the engineering analysis #2 (above), the final design weighed over half a metric ton. Because the project was built off-site, we had to modularize the ramp, the overall deck, and the individual sensory elements to ensure they could be safely transported without exceeding vehicle payload limits or damaging the finished aesthetic details. We completed all framework construction and exterior painting prior to delivery so the client could access the structure immediately upon assembly. Passing our on-site physical tests—which included successfully supporting four team members on the top deck with zero structural flaws—validated our prior simulations. Ultimately, applying our engineering skills to deliver a safe, durable, and fully customized space that directly supports a family’s daily life was a profoundly rewarding experience.
