Origin and Pivot

 

The origin and pivot of an object are usually at the center of the object. But you can move both the origin and the pivot elsewhere to make complex movements easy.

Terminology

Every object in a 3D scene has an origin : a specific point in space which defines the location of that object. The origin is usually invisible, but it’s easy to see: when you transform the object (like translate it, or scale it) the lines of the gizmo intersect at that origin point. The origin is used for scale and position transformations to the object.

 

Objects also have a pivot : a specific point that defines where rotations of the object are applied. Like the origin, the pivot is also usually invisible, but appears when you rotate the object. It can also appear as a small red dot in the scene when an object is selected, and the pivot of that object has been moved from its default position. This serves as a visual reminder that the pivot is in an unusual place. The pivot is used for rotation transformations to the object.

 

Default Locations of the Origin and Pivot

  • When you create a simple primitive (like a Box), the resulting mesh has an origin at the mathematical center of all the points which make up the mesh.

  • When you import complex geometry (like a .step file), that mesh has an origin where the creator placed it.

Changing an Object’s Pivot Point

Some geometry, when imported, can have a strange origin setting. This can position the imported mesh to a distant (or even invisible) location in the scene. Reset any mesh to the scene origin by right-clicking the mesh’s name in the explorer, then selecting “Center Geometry to Origin”.

Creating Multiple Pivot Points

 

By default, the pivot is at the origin of the mesh so any rotation to an object makes it spin around that same point. What if you want the pivot someplace else? For example, what if you want to rotate a planet object around a star, not around its own axis? You can move the pivot point.

  1. Edit the pivot point logically by editing the [x,y,z] of the pivot in the object’s properties.

  2. Edit the pivot point visually by clicking the Move Pivot button in the object's properties to show the pivot point in the scene. Drag the handles on the pivot point to move it.

 

You may want complex rotations, such as a planet that rotates both around its axis and around a star. Every object can have only one pivot point, so it may seem complex rotations like this are impossible. Not true! Use groups to add additional control points and transformations to your object. You can place an object into a group, and apply a different rotation to that group. Repeat the process (place the group inside a second group) to create another pivot point. In this way you can create an articulated robot arm (wrist rotating to elbow rotating to shoulder), a solar system (moon rotating around planet rotating around sun), or other complex combinations of rotations and positions. Learn more about rotation modes .

 

Agreeing to a Common Understanding of an Object’s Origin

By default, the origin of any mesh is usually in the mathematical center of the mesh. For many objects, like circular or radial objects (a gear or a pipe socket), this makes sense.

 

 

However, you may consider placing the origin of your objects in another place, such as the lower, left, front corner of the object. For square objects (like windows, floor tiles, server racks), or irregular objects that must fit into or align with a grid-based space, having the origin in a predictable corner of the object could simplify the math required to position it.

 

 

There’s no right answer. But consistency in the placement of your origin across your meshes can help minimize calculations, especially with nested scenes.

 

Changing an Object’s Origin by Placing it Into a Group

You may want to permanently change the position of a mesh’s origin. Before you do, consider if this mesh’s geometry might change sometime in the future (for example, it’s a part your company sells and that CAD part might be updated by your design team and then you’ll have to re-import it into the scene). If the mesh may be imported into the scene again, then don’t modify that mesh extensively. Rather, use this first technique: place that mesh into a group. You can apply your transformations to the group, and leave the original geometry untouched (and easy to replace sometime in the future).

Changing an object’s origin by placing it within a group

  1. Create a new group in the explorer.

  2. Drag your mesh into the group to make it a child of that group.

  3. In group properties, move the group’s origin or pivot to the location you want.

That’s it! Now, apply a rotation or transformation to the group: you’ll see your mesh update.

Remember to only use the group for your transformations now, not the mesh.

 

Note: When dragging a mesh into or out of a group, you can choose to preserve the mesh’s current position, or to allow the move to modify it. Click the gear icon at the bottom of the explorer to turn on or off position preservation.

If your mesh’s geometry is unlikely to change in the future, and won’t be imported again, then it’s worth taking the time to move the object’s origin instead of creating a group for it as described above. You will use the “Transform Vertices” feature to move all the vertices, leaving the origin in place. Then collapse the transformation to make the change permanent. Here’s how.

Consider a simple box mesh, dimensions 1x1x1, with an origin at its mathematical center (at the midpoint of its height, width, and depth).

Here, to make the red pivot dot appear which helps visualize the origin, we nudged the pivot x from 0 to 1 and then back to zero. This is not required.

  1. Select the mesh.

  2. Create a new “Move Vertices” feature.

  3. Set the transform center to “Mesh Pivot Point”.

  4. Shift-drag over all vertices of the mesh.

  5. Translate the mesh so the origin is aligned as you like (here, we set the translation to 0.5 for x, y, and z).

  6. Click one of the 3 gizmo buttons above the “Edit Vertices” button to redraw the screen and confirm your move.

  7. Repeat the previous two steps as necessary.

  8. Apply your change permanently to the mesh. First drag this “Move Vertices” feature to the top of the feature stack. Then click the context menu of the feature, and choose “Collapse to here”.

 

See the origin is now moved with respect to the mesh.

 

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