Making my rollocoaster rail twist

maarten_moris

Hello everybody. My name is Maarten, and i am from the Netherlands. I wil try to explain my problem in my best English.
I am rebuilding my rollocoaster and i want to print curves with banking (sloping) like in the real world. Here is a link to wat i made so far
https://cad.onshape.com/documents/5e5ba349d1a75781beabaaa1/w/aa0add89ff9faa0c6a9691a4/e/350184337d935d15195107e2
I have to print the 180 degree curve in two pieces because it is too big for my print bed, so each curve is 90 degrees.
The curve has to start horizontally (zero degrees sloping), and then create some 40 degree "sloping" . The second half starts at 40 degrees en ends again horizontally. when i put them together, i wil get the 180 degree curve. I can only find a way to create banking on the total curve. I hope someone can help me with my problem.
Thank you.

Maarten

S1mon

To really design a real modern steel rollercoaster, you'd probably need to use specialized tools, but within Onshape you can do a decent approximation. The challenge will be that all the transition curves need to be degree 7 or higher in order to have smooth acceleration from straight to curved or from flat to banked sections. Then you also need to have pretty good parallel curves for the centers of each rail (within some tolerance). These will always be approximations, and will have some small wobbles in the curvature.

You can start by using Bridging curve with curvature, but it will be challenging to avoid big acceleration discontinuities.

S1mon

To really design a real modern steel rollercoaster, you'd probably need to use specialized tools, but within Onshape you can do a decent approximation. The challenge will be that all the transition curves need to be degree 7 or higher in order to have smooth acceleration from straight to curved or from flat to banked sections. Then you also need to have pretty good parallel curves for the centers of each rail (within some tolerance). These will always be approximations, and will have some small wobbles in the curvature.

You can start by using Bridging curve with curvature, but it will be challenging to avoid big acceleration discontinuities.

MichaelPascoe

@S1mon I believe this is for Lego's.

@maarten_moris
There are a few different approaches you could take. If you are going for a build a coaster one segment at a time, you could use configurations to help speed up the process so that you only have one model that is inserted multiple times. The trick to getting the configured track segment working well will be two custom features you can add to your tool bar.

I recommend completing the Learning Pathways in the Learning Center before you get started.

Sweep normal by @mahir. This will let you sweep the rails while keeping alignment.
Path pattern by @Konstantin_Sh. This will let you pattern the supports while keeping alignment.

Here is an example of how to insert and snap configured parts into an assembly:
https://cad.onshape.com/documents/ed4854784a976b004aa8b988/w/c903869eb24eb1923ab12990/e/640174d836e83...




And here is an example of a configured track segment part studio:
https://cad.onshape.com/documents/ed4854784a976b004aa8b988/w/c903869eb24eb1923ab12990/e/0d36e74d...