The spin tool in Blender 3D is a powerful tool for making lathed-looking objects and making radial arrays of objects. In this article we prove this by making a model of a toy rocket.
All About Spin
The point where you go from being a beginner to a master of Blender, or any other 3D program for that matter, is when you stop placing things by hand and start modelling with precision by placing objects and part of objects (or points of geometry) using the built-in modelling tools.
This is never more true than when you try to model objects which in the real world would be turned on a lathe out of metal or wood. Such things include table legs, light sabres, sonic screwdrivers, and bottles.
Using the spin function in Blender makes it possible to do two essential jobs when making models:
- spinning a shape around a single axis just by drawing its profile, and
- positioning smaller objects in what they call a radial array.
The best way to demonstrate this is to make a shape which is made of both types of shapes, in this case a toy rocket.
Rocket Body with Lathe
The first step towards making a turned or lathed shape is to draw the profile of the shape you want to make. This is the line which will be spun around a central pint, usually the 3D cursor, to make the lathed shape. Let’s get started.
Add a cube with “Shift + A.”
We are not going to use this cube. Instead we are going to delete the existing points and add some more of our own. Enter edit mode by pressing the Tab key and select all by pressing A.
Now delete all the vertices on the cube. Press the Del key and select “Vertices” from the pop-up list.
Now you need to make the profile, the curve you are going to spin into the body of the rocket. First you need to make some new vertices in a curve. Go to the front view by pressing 1 on the number pad. Then make sure you toggle the orthographic view. (You can tell you are in ortho because the grid is visible).
Before you go any further make sure the cursor is positioned in the centre point. Press “Shift + S” and choose “Cursor to Center.”
Make sure the centre of your object is in the centre of the grid by pressing “Shift + S” and selecting Selection to Cursor.
To make new vertices, hold down the “Control” key and click with the left mouse button. You will make a string of vertices connected by edges.
If any of the points are not where you want them you can click on them and press G to grab them and move them around, pressing left mouse to place it or right mouse to undo and snap it back to where it was.
When you have the shape you want, select all by pressing A (all are selected when they are orange).
Now go to a top view (by pressing 7 on the number pad), and look for the Spin button on the left hand Tooldrawer. Press spin and the curve will spin around the cursor and produce faces as it goes.
Adjust the Spin settings on the bottom left to make the Steps 10 and the angle 360º to make 10 faces. An angle of 360º makes the shape spin all the way around and complete the shape.
We used 10 faces to make the rocket body faceted like an airship, but the more steps you put in the smoother the rotated shape will be.
Now the body is made.
You will probably notice there are holes in the top and bottom. You need to close those to make a filled shape. Use “Box Select” to select the point around the hole at the top.
Note: make sure you haven’t accidentally selected some points on the other side of the shape, and if you have deselect them by holding “Shift” and pressing the left mouse button.
You can join the ends by pressing S to scale the the points into the centre and then pressing 0 to snap them to 0. Press the left mouse button to accept the new position.
Do exactly the same on the hole in the bottom.
Now select all points with A and click Remove Duplicates to make the point at the top and bottom single points rather than overlapped points. Save your work before moving on to the next step.
Adding fins
Now we need to add fins to the body by copying them into a circle around the body. To do this come out of edit mode (by pressing the Tab key), and make another box with Shift A and Mesh->Cube.
With the new box selected tap the Tab key to enter edit mode again, select face mode, then select the faces on both sides and push them together to make it thin.
Now select the end face and move it down on the outside to make a fin shape.
Note: if you want to you can smooth the fin out by adding a subdivision surface. If you do this you might also want to add a loop cut to the box on the inner face, to make the inner face flat and flush with the surface.
Move the fin till it intersects with the body at the point you want all the fins to be.
Now select all of the box with A and press the Spin button. This makes a radial (circular) array of copies of the selected object in a circle around the cursor point.
Adjust the spin settings as before to add more or less fins. We kept it at 10 to match the faces of the body.
Actually it looks less like a toy rocket with all those fins than it does a Nerf beachball, but you get the idea. To place all those fins by hand would take a lot of work, and you would never get that machine-like pixel perfect precision by hand.
Conclusion
Spin is all about rotating things in space, either points or objects. This way you can make a wealth of lathed or turned objects or make radial arrays of objects, that is to say objects automatically arranged in a precise circle. The uses for it are limited only by your imagination. The vanes of a windmill, the blades of a jet engine, the buckets on a ferris wheel, a circles of columns in a church. Any time you need a lot of things in a circle, this is the tool you will use.
If you enjoyed this tutorial or have any questions, please let us know in the comments below.
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