How to draw a 3D winding in COMSOL Multiphysics ( Toroidial inductor , UU core transformer )

In this video I show you how to draw a 3D winding in COMSOL. Ravi Kumar has made a winding model, but he used Sharper3D to make that. I decided to step-by-step show how to make a winding directly in COMSOL. we can use these to model inductors and transformer in COMSOL. Story behind this video is as follow: I wanted to make a video about my solid state Tesla coil. In it, I used a voltage regulator so I decided to explain that first. In that there is a Diac and Triac, so I decided to explain them first and model them in Simulink. To model them we need to use Zener diode so I said, I make a video about Zener diode first. In the preparation, I wanted to show the functionality using real components and while doing the experiment I realized that city electricity waveform is very distorted at my home. Naturally I decided to make a video about that. To make my points clear in that video I wanted to show some non-linear loads like LED. So I needed to measure the current waveform of a LED. At home I don't have a current probe, so I decided to make a current transformer. I observed that the waveform of my current transformer is distorted. I decided to first make a video about how to design a current transformer. The ferrite core that I have at home, I bought it many years ago so I did not know the permeability of it, so in my video I could not say what is the material of that ferrite core. So I decided to make a video and show how to measure permeability of a material. I 3D print a plastic toroid similar to the ferrite core that I have. I wanted to calibrate my measurement using a material that has permeability of 1. After finding the inductance formula for a toroid analytically, I noticed that the value does not match with measurement. Looking at Grover book and some other publications, it became clear that those simple analytical formula have limitation in accuracy. I decided to make a video and show how to measure and calculate inductance of a toroid. I needed to do 3D modelling to calculate the value of inductance numerically. The question was, how to draw a toroidal winding. That is why I made this video. Hope I can go back through this list and make my SSTC video one day, lol. We have passed the 1000 subscribers with approximately 220k view. That is an achievement. Finance: N=37 subs=1013 Available budget (N): 1013-100-37*(37+1)=-493 Storage limit: 2^ln(1013)=121,15