Using the 3D Cursor in Blender
Intro
Hey guys, what’s going on! In this video, we’re going to take a look at how to use the 3D cursor in Blender. The 3D cursor is, if you take everything and delete it, it is this little circle here in the center. That is the red and white circle; the little crosshair thing. In 2.8 and above, they have added a special 3D cursor tool to allow you to move and drag the cursor around. If you’re familiar with any kind of word processor or typing code, it’s very much the same idea. A cursor is just a thing that helps you know where you’re working.
First Example
For example, if I hit SHIFT+A on the keyboard that will bring up the “Add” menu. Let’s just say I want to add a cone. This will add a cone to the scene, but it will add it exactly where I’ve put my 3D cursor. So for example, I can take the cursor tool, move the cursor way over here, and add a monkey head. That monkey head will appear here, exactly where I’ve put the cursor. So that’s cool, to have it put stuff exactly where I want it to appear. Especially if you have a massive scene and you’re adding stuff all over the place. If I want to add something way out here I can do so without having to go all the way up and get something that appeared somewhere that I didn’t need it to appear.
Another Example
Another great use for the 3D cursor in Blender- you can hit SHIFT+S to bring up the snapping menu popup; and this is especially useful if you’re going to do some editing. So for example, if we bring up the monkey Suzanne here for a second, and I hit TAB on the keyboard to enter edit mode. Let’s just say I want to create something in the center of Suzanne’s eyeball. I’m going to hit X on the keyboard and delete the center vertex on the eyeball. So that is going to open up a hole in the eyeball. Next, I’m going to hold ALT on the keyboard and click this edge and that’s going to select all of the vertices inside of this eye socket area. And so what I can do is go back to the SHIFT+S menu to bring up the snapping popup. Then I can choose to snap the cursor to what I have selected. So the cursor will appear exactly in the center of the eye. So then I can go and add a cone or something that will be specifically in the center of the eye.
The pivot point menu
Actually, that was not a great example because I have ‘active element’ currently selected. So this menu up here is the pivot point for transforms. I’m going to choose 3D cursor and then let’s see the difference that that’s going to make. So I’m going to go ahead and add a cone and it’s going to scale it now, this time, scaling from the 3D cursor. It’s a great reference point to be able to pivot scales and rotations around an element or a point that’s not a vertex. So if I go to- this is what I had it on previously- the active element, so here, you can see I’ve selected all the vertices on the bottom of this cone; whichever one (I’m shift-clicking) is white is the active selection, so it will scale from that point. So anyway, the cursor is always available if you’re trying to scale something, rotate something, or create a pivot point, or define or create a center on something, the 3D cursor is a great way to do that.
The Door Example
Okay, here’s a good example use case for the 3D cursor: Let’s say for example, I want to model a door. I might start with a plane and I might rotate it on the X axis for a little bit and scale it along the X. And this is just a rough, general idea for the shape of my door. But when I rotate it like this, it doesn’t rotate quite like I want it to. So an important concept for animations especially, is the idea of knowing where your pivot point is. Usually on all objects that are added through the context menu have the default pivot point (or ‘origin’ as it’s known in Blender) located in the center of mass. Of course, if you model a lot of new geometry onto a base shape, the origin will remain exactly where it was in object mode, even if you completely change the location of the whole shape.
So back to the door example, I want my door to rotate from the edge, like a normal door. So what I can do is go into edit mode, and have edge selection mode enabled, and select the left edge. Then hit SHIFT+S to bring up the snapping menu, and choose Cursor to Selected. That’s going to bring the cursor to the center of these two vertices, basically the center of this left edge. Then hit TAB to go back into object mode, and in the pill menu at the top, choose Object > Set Origin > Origin to 3D Cursor. The origin defines the point at which the object will rotate and scale. So if we hit S on the keyboard to scale the object, it will scale from that left edge.
Using the Cursor to Scale and Rotate
Another example, if we go back into edit mode and choose vertex selection, and choose the bottom left corner, we can SHIFT+S to snap the cursor to that selection, go back into object mode, and then choose Origin to Cursor. Now the origin is at the bottom left corner, and we can scale it from the bottom left corner. That is a super useful case for the 3D cursor in Blender if you’re modeling something or if you’re animating something, and you need it to scale or rotate around a specific point, the 3D cursor is a really great way to set that location.
Enjoyed this video? Check out more on modeling in Blender!
