Software and Editing STL Files
Figure 1. NX-edited model of slopes in Jackson Hole
Figure 2. Rhino-Edited Prototype Print of Jackson Hole hiking Trail Section
The importance of using a powerful STL editing tool cannot be understated. That is why we tried multiple programs, and the figures above show the results of editing attempts using different software. Since our last update, we have found that NX is not the best software to use as shown in Figure 1. The slopes took a long time to create, and they also appeared very far from a realistic representation. The main reason behind that was many of the trails were sketched manually using NX and then extruded to the same depth. Some areas seemed to be deeper than others as shown, especially in the parts where the elevation of the slopes changed. Although we can make extrusions in smaller sections using NX, the process is tedious and inaccurate. The team tried to use online tutorials to learn how to sketch using smaller mesh areas in Rhino and it produced smoother and better looking results of the trail as shown in Figure 2 above. The trail did not appear to have inaccurate representations of elevation because of sketching, as opposed to what was obtained using NX, and maintained a realistic look. The printed part looked promising and we will add more geographic features such as longer trails, which raised another issue with Rhino. Rhino lowers the resolution of the STL file we import if it has too much detail and makes it very hard to follow the mesh in order to create the trail. We are curious on whether Meshmixer will behave similarly or would be easier to use. A team member, Ahmed, is currently comparing both softwares and then we will proceed to print our last iteration.
Preliminary results in comparing the two softwares show that each software has a specific use. Rhino uses a technique called Freeform Surface Modeling for CAD drawings. It creates surfaces that can then be manipulated using nodes. Rhino allows us to easily divide the STL file into nodes, and gave us the ability to change their location and create the trails we want. One issue that we saw while using Rhino is that it tends to make the landscape less accurate. On the other hand, Meshmixer is a 3D surface sculpting tool that uses brushes to change the surface as required. Although Meshmixer is very useful it is hard to use for our purposes – creating trails – and further investigation of its capabilities would be required before we can use it.
Printing Techniques
After running initial prints with FDM, we saw some interesting results. FDM prints showed us how size and scale settings affect our final product in terms of detail. After our first run, which was a small part that tried to show many features, we decided to print a second, larger part that zoomed in a few select features as shown in Figure 1. With FDM we saw layering effects that obscured some key trail and elevation details which we believe could be prevented when we use SLA/ SLS for the final print this week.
Figure 3. STL of the Plateau Point trail in the Grand Canyon
Using the results obtained from our final prints, we learned about manipulating STL files and the amount of detail that can be achieved on these maps through 3D printing. We decided to print a hiking section of the Grand Canyon for the final print, because we believe we can convey a good amount of detail to the user of our map using this trail using the available tools. Figure 3 shows the STL model that we will modify to reflect the hiking trails. The Grand Canyon trail chosen has significantly varying contours with great details that we believe will test the accuracy of our print and will more prominently reflect any changes in print settings. We have decided to test how print settings such as the size of the print will affect the print details as we have printed our first part at a size of 160mm x 160mm and the second part was 100mm x 90mm. Our final motivation behind this is to test how fine a detail we can achieve through FDM by the end of this project to compare it with an SLS/SLA print if possible, and the balance that can be achieved between cost, detail, size and utility to the reader.
Final Week Plan
- Compare Meshmixer vs. Rhino for STL manipulation
- Print Grand Canyon STL using FDM and compare details
- Using SLA to fine-tune our final product
- Adding accessibility features to trails (stops, markers, etc.) if time allows
- Work collaboratively on presentation and final report
Kelsey Hacker, Alston Benz, Ahmed Aljneibi, Adel Alkaabi, Naif Abulleef