Tricks and Tips :
How to make a coil around a torus!

Using the radial Array tool and its replace Path with Curve feature we will create a torus coil in just a mater of minutes. Once again, holding true to the spirit of trueSpace, it will take you longer to read the tutorial than to actually do it!




Open the object info panel with a r-click on the Object tool. Place a default cube (set units to meters) on the grid and click on the Radial Array tool. R-click on the Radial Array tool while you are in the area to bring up the properties panel. Click and drag away from the cube to create the default array. R-click on the array to expose the manipulator. On the Radial Array properties panel make sure that “Toggle Circle” and “Toggle Follow Path” are pressed.

Overall screen

Open Object Info Panel with a right click

"Toggle Circle" and "Toggle Follow Path"




Close-up from previous screen - shows placement of cube, click drag location to create
the array, and then the manipulator to increase the number of items

Left click drag to the left on the manipulator as shown above to increase the number of cubes to 21. Does not matter as it will change later but it gives us something to work with. Click on the hierarchy down arrow to select the primary cube and scale it down using the manipulator. You will have something that looks like below.

Overall screen, after scaling

Click "Hierarchy down" and scale one cube




Create a 2D circle curve with a click drag. Mine ended up around 10 meters in diameter.

Overall screen, with the circle in the 2D draw panel

Close-up of the settings




Turn on the grid tool and r-click on it to bring up the properties panel. Turn on rotation and set it to 45 if it is not already. Use the draw Panel manipulator to rotate the curve 90 degrees. It should be two snaps as each will be 45 degrees. Notice the rotation change in the Object Info panel. Turn off the Grid tool.

Activate rotation (top of overall screen)

Overall screen

Rotate to 90 degrees, with grid snap of 45 degrees

"Grid Snap" icon, and draw panel manipulator




Left click on the array to select it and then Right click on the array to activate the controls. Click on the Replace Axis tool and select your circle curve. It looks really weird at the moment but don’t worry, here is where the magic begins. You can delete the circle now if you would like.

Overall screen after replacing the axis - looks weird!

The "Replacing axis" icon, bottom of overall screen




Now, in the Radial Array control panel type in *12 after the 360 entry (360*12) for the Angle and press Enter. The math is done for you. Set the # of segments to 191. Must be an odd number. Set the Begin Radius to 1.7 or something close. Now this looks a little more like something we would expect. Play with these settings and experiment a bit. If you want a Torus Coil made up of separated parts you can skip the next three sections.

How things look after typing in some settings

Here's the Radial Array info panel (close-up of bottom left of other image), showing the settings that were entered



To create a continuous solid torus coil, first click on the Create Copy of Path tool. A curve will be crated through the Path of the array. Move the Path in X a little so you can see it better.

A look at the overall screen

The "Create copy of path of radial array" icon, with the x location adjusted so it can be seen better

The manipulator icon, which you can use to move the x location of the copied path




Create a small regular polygon and loft it around the torus coil curve by selecting the Loft tool and clicking on the coil. Note that the polygon will disappear. Save your curve to the curve library first if you want to experiment with different sizes of polygons.

Overall screen, showing small polygon lofted along the copied path

Close-up from above - note the small polygon on the right of the image (with the create polygon icon highlighted in the centre), and the "Loft Surface" icon. To the left is the Curve Library, where you can save your curve for experimentation.




Save your array to a library if you want and delete it from the scene. You can leave your coil as a NURBS object but I converted it to a Polyhedron with the Convert Nurbs Patch tool. A R-click on the tool will bring up the properties. Set the Static res. to 1 before you convert. I applied a single SDS operation. A R-click on the SubDivision tool brings up the property panel of the SDS tool so you can extract the mesh. This gave me the hand drawn wire look I wanted.

Overall screen

Close-up of bottom left - the convert NURBS to polygon icon is on the right, with the SDS icon in the centre, and the object library (and icon) over on the left


The conversion settings for NURBS to polygon, and extracting the final surface from the SDS object.




Rotate in Y 90 degrees and normalize the location. Create a torus primitive (Riclick on the tool to bring up the settings) and normalize the location while it is still active. Then left drag on the red part of the ring to adjust the radius, left drag the tan part to adjust the Spherical Radius, and R-drag the blue diamond to adjust the resolution. My settings are as shown in the image.

A look at the overall screen

To the left is the "Create Torus Primitive" icon, and on the right, the "Normalize Location" icon

The Torus Primitive Settings (split into two here for readability)

The magic ring in close-up - adjust the look of your torus using this




Your Torus Coil is now complete and ready to be textured and rendered. I used the Copper metal from the “Metals” material library and a modified Fire Ball material from the “Materials” material library as shown. R-click in the library window for your options.

The overall screen for texturing (real time display)

A close-up on the material settings - note the Material Emission icon on the left, and the Material Emission settings panel on the right

A close-up of the material libraries

Choosing the copper material from the "metals" library




I hope you had fun with this little tutorial. The technique is quite powerful and really amazing to experiment with. Until next time!

Another render of the finished object!


This tutorial was originally posted on the's 'Tricks-n-Tips' section.
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