Surface Modelling, Geometry Trends, and Growth: Julia’s Internship at Velobike Innovation
Hello, I’m Julia! I joined Velobike Innovation as an Industrial Design intern at the beginning of the year, working on a project centered around frame design. I grew up in Wellington, where I did a Bachelor and Master’s in industrial design.
For my Master's project, I designed a customised bicycle saddle made using pressure mapping and 3D printing technology that combines rigid and flexible material. The result is a saddle that has different stiffness zones tailored to the individual rider.
My cycling experience is quite casual, consisting mainly of riding around Wellington on my gravel bike, and giving bike packing and mountain biking the occasional go. In terms of track cycling, I have done a few beginner sessions at the Hataitai velodrome and braved a couple of laps at the one in Cambridge.
Role at Velobike Innovation
The project I worked on during my internship at Velobike Innovation was focused on the concept development of a track frameset. This included background research into design and geometry trends, as well as the 3D modelling of the frame.
A strong focus of the internship was on the digital process of surface modelling and learning the workflows around it. This was a steep learning curve which involved learning a software that was new to me, called SolidWorks.
SolidWorks functions in a parametric way, meaning surfaces and forms are based on certain input parameters that can be altered further on in the design process, enabling you to go backwards in the CAD process and make changes (to an extent). It also requires a certain order of operations of moving from an additive modelling process involving solid 3D shapes, to detail work which involves trimming these solids into surfaces and creating blends between these junctions.
Process
Design Trend Research
The first phase of this project consisted of looking at existing frames and comparing their features and forms. By getting the opinions of the Velobike crew and looking at what is new on the track market, I developed a better understanding of the design language around track frames, and what forms a new frame concept could take.
Geometry Trends
To gain an understanding of track bike geometry, and specifically where Velobike’s M2 frame sits, I mapped out the geometry of around twenty framesets and analysed them for trends. While there weren't any strong statistic correlations most of the time, visualising where different framesets sit for different geometry dimensions proved to be a helpful comparison tool.
Stack and Reach, and Reach over Release Date - with the red dot being the M2 frame, and blue being the Altias frame. Dimensions describe size L fames.
Some of the key findings from this phase were that compared to other track frames, the M2 is more upright and less aggressive. The reach of the Size Large M2 is a bit shorter than average, and the stack height is exactly ‘on trend’. When I examined track frames, their dimensions, and when they first appeared on the market, it became apparent that the stack/reach ratio has not substantially changed in the last decade.
However, the wheelbase dimensions of track frames have increased over time, and the M2 wheelbase sits well below this trendline. The seat tube angle also looks to be slightly increasing over time, with 75° becoming a more common choice than 73.5°, though the small sample of data points also limits the assumptions that can be drawn.
By comparing the front centre dimension, which is the distance from the bottom bracket to the front axle, of different frame sizes, it becomes apparent that this varies drastically between bike models.
A larger front centre dimension contributes to the overall wheelbase length, and correlates to the increase in reach that we have been seeing. With bike fitting trends leaning towards fitting athletes with a longer reach position and placing them on frames that are conventionally oversized for their height, this is an interesting dimension to examine.
Concept Sketches
The next design phase consists of creating concept sketches. This includes form sketches, as well as entire frame concepts, and brainstorming what specific areas of a frame could look like.
Basic form study of top tube and seat tube junction.
The sketching process.
Concept 3D Modelling
After sharing my concept sketches with the team and gathering their insights, a clear rationale for the new frame began to emerge. The goal was to modernize the M2’s geometry and style while ensuring the design remains cohesive with Velobike’s brand identity. By refining the frame’s flowing surfaces and integrating horizontal detailing, the aim is to preserve the character of the M2 while giving it a sleeker and faster appearance.
My approach to designing specific areas of the bike, like for example the seat tube and top tube junction, was to sketch out different variations, and then use these sketches as a basis for moving into the 3D modelling process. For this specific area of the bike, straight lines are a more common design choice; however, I was drawn to using a softer radius that still preserves a visual resemblance to the M2 design. Wanting to maintain this, I spent some time refining the 3D modelling process, learning about the different methods for blending the flat surfaces with the curved corner. This took some trial and error, as the order of operations has a strong influence on the way surfaces blend into each other.
Screenshots of the 3D modelling process.
The 3D modelling process was very iterative, especially the process around experimenting with different techniques for blending surfaces at the junctions between different areas of the bike. I found that the overall focus lies in achieving the right balance between smooth transitions and sharp creases, with the greatest challenge being around producing surfaces that flow as intended.
This general workflow consists of creating sketches in 3D space, which map out the cross sections and outlines of each tube. Extruding these into pipe-like surfaces creates the basic building blocks, which are then divided into smaller parts through split lines. These split surfaces into smaller surfaces, which can then be connected to the edges of other surfaces to create the forms that make up the frame.
A key learning point from this process was that the surface modelling requires a lot of planning, which involves mapping out where creases and blends sit, and how they interact with each other. I also learning that the surfacing process is cyclical: sometimes surface A can be used to make surface B, which in turn can be used to remake surface A to look better.
Building on these insights, I developed a more refined concept that showcases the new design language. As this is still well within prototyping phase, moving from concept to a fully realized bike will involve many more steps, like fine-tuning the design, creating a production-ready 3D model, and of course the physical manufacturing side of things.
This internship has been a deep dive into the world of track cycling, from learning the terminology to understanding the nuances of bike geometry. I’ve learned a lot along the way, with plenty more to learn about the frame design process. Moving forward, I’ll be looking forward to learning more advanced surface modelling, and perhaps giving the velodrome another go.
Julia Sasse, 2025.