Week 6-7 Submission: Project Tramways Stuart Steinfort S3137921
CAD Iteration 1: The first iteration of the tram CAD model was commenced after the week 6 class. This involved refining the utilitarian box-like form of the chosen concept so that it could be used within the SolidWorks program. The form was refined in the sense that greater definition of shape was sought in the complex curvatures and their subsequent transition.
figure 1 - 6 The first CAD model in construction elements
The drawings were inserted and scaled in SolidWorks to the dimensions of a 1:1 tram. The ensuring days saw the construction of the side profile. This was initially done through an extruded sweep which defined the scalloped side profile. The sweep was guided by a number of profiles which sought to control the scallop in its varying size and depth. This file was made into a solid and milled in the 4 axis CNC mill. This allowed a scale model to be produced at approximately 1/25 scale. The size restriction was due to the CNC mill bed limits. This meant that the model was split into two, milled separately and then glued. The milling took approximately 3-4 hours to compete both objects, with some minor difficulties with the foam and the sharpness of the mill drill bits. The feedback given was extensive in addressing all surfaces as well as the overall concept. The underlying point was to change the method of construction to surface lofting in order to gain greater control of the surfaces. All surfaces had suggestions for further development, from both a practical and concept perspective.
figure 7 -8 The first CAD model in the process of being milled, and the final model.
CAD Iteration 2: The second iteration was the first attempt to respond to the given feedback. As can be seen in the image (figure 9) the first model has been used. The model has its top surface cut off with various lofted surfaces fixed upon it to improve the roof outline. The model itself was quite rudimentary in construction, with poor surface transitions. It did though allow insight into the techniques of lofting.
CAD Iteration 3:
figure 9 The second CAD model, the highlighted parts illustrate the modifications.
This third model was a completely new model which is entirely constructed from lofted surfaces. As can be seen in the images, the model started with lofting the outside edges to create a framework of the model. Again a background drawing and basic underlay was used in order to create the correct size. This process involved a significant amount of lofting, adjusting and fixing the surfaces until the desired outcome had been reached. The form was adjusted for taper both from the top and side perspective. This created the need for three dimensional sketches to guide the various lofts. This was done through projecting two dimensional profiles with surface extrudes which created the desired line upon intersection. Once finished, the inside ‘scalloped’ surfaces were constructed by projecting offset curvature lines onto rebated planes. This allowed for gradual construction from the bottom to the tops of the model. Again a significant amount of time was involved in adjusting the scallops until correct. The model’s roof, front face and floor were lofted with gradual taper. This again added depth in form to previously flat surfaces. Likewise the side windows were slanted on a three degree angle, with the front section split and angled to provide greater emphasis on the driver section. This final model could not be completely knitted together at the time of writing. I am currently seeking advice because of the difficulty I have found. Regardless, the model is complete enough to be milled in order to judge details in a physical sense. This model is being milled at the time of submission.
figure 10 - 15 The third CAD model in various points of construction. As can be seen, each surface is lofted individually.
Reflection: The past two weeks have passed considerably quickly. Through that time I have done a significant amount of computer modelling, yet I feel the project is behind. In the coming days, while the CAD model is being milled, I plan to develop and define the interior of the tram. In addition I will respond to the mid semester feedback concerning the system. This I hope will brief the CAD model in further developing. I endeavour to create a scale model every week in order to push the concept to a resolved solution. I feel this is an appropriate manner to develop a form before the project commits to the final scale prototype.