by Michel's add-ons & more in Scripts and Addons

Ortho offers a collection of tools that allows you to move, rotate, scale, snap and align selections of a mesh relative to a user-defined reference plane.

Working relative to a reference plane can greatly simplify the positioning of mesh parts and can help clean up distorted meshes. Blender already offers several tools to transform and snap mesh parts but they work in the context of predefined coordinates, which makes it difficult to position or align mesh parts in meshes that are transformed with respect to their local coordinates or in situations where orthogonal coordinates are not sufficient, for example when positioning a window inside a slanted roof.

Ortho offers a simple and interactive way to define a plane that fits a selection of vertices in a mesh and offers a set of tools that operate with respect to this reference plane. You can, for example, align and snap a selection to the reference plane or move this selection along its normal or its surface. Scaling is also an option, offering ways to rectify slightly distorted meshes even in situations where such a distorted plane is not aligned with any axis and scaling along individual normals with Alt-S gives strange results.

[Note that a full and up to date version of this documentation is included as a PDF file in the product]


  • Initial release
  • Multiple reference planes
  • Flip normal button in display
  • UI tweaks
  • Added missing documentation on display options


Installing Ortho for the first time is simple:

  • Unpack the .zip file 

you probably already have done that as it contains this document (Orthousermanual.pdf) and the add-on itself (an archive with Python files, orthoyyyymmdd.zip, where the yyyymmdd portion of the name is a timestamp that may vary)

  • Select File → User Preferences ... → Add-ons from the menu

  • Click ‘Install from file …’ (at the bottom of the screen) and select the orthoyyyymmdd.zip file

  • Click ‘Install from file ...’ (at the top right of the screen)

  • Check the enable check box to the left of the add-on you just installed

The add-on operators will now be available in Edit mode from the Ortho tab in the 3d-View Toolbar (press Ctrl-T if the toolbar is not visible).

Installing a new version of Ortho

If you want to replace a previous version of Ortho you have to remove the old version first. To do this, go to File → User preferences … → Add-ons and either search for Ortho or go to the ‘Mesh’ category where it will be located. Click on the add-on and then on the ‘Remove’ button. After removing the old version follow the instructions above to install the new version.


The tools that Ortho offers are available in the 3D view in edit mode. They can be accessed in two ways. The first is as a list of buttons in the Ortho tab of the Tools area (press ctrl-T if the tools are not visible).

The second way is as a pie menu that will pop up if you press Cmd-O (that is the ‘Windows’ key or ‘Apple’ key on most keyboards plus the letter O. Press both at the same time).

You can disable this shortcut in the add-on preferences and configure a different shortcut in the File → User preferences → Input section if you like. The add-on preferences section also give details on which operator name to use to achieve this.

Tool & options reference


The PlaneFit tool will create a plane that best fits any selected vertices. It will show the normal and its x and y axes in cyan, green an red respectively, and the plane in semi transparent white. These colors can changed in the add-on preferences.

You may change the size and toggle the visibility of the plane with the options in the Ortho panel in the 3d-view options (press ctrl-N if the option panel is not selected)

The center of the reference plane, the centroid, is displayed as a small white dot.


Although the reference plane is infinite it is displayed with a finite size. The directions of its x and y axes are aligned with the major directions of the vertices it was fitted to. By checking align you have the option to select which coordinate system to use to which the x and y axes will be aligned as well as possible.

Principal will align the x-axis with the most common direction of the selected edges while local and global will try to align with the x and y axes of the local and global coordinate systems respectively.

Flip normal

Reverse the direction that the normal is pointing.


The Align tool will align selected vertices, and possibly connected geometry, to the reference plane. This is accomplished by fitting a plane through any selected vertices and rotating those vertices in such a way that this plane will be parallel to the reference plane.

Optionally the vertices will be moved as well so that the median point will coincide with the reference plane or even to the centroid.


This option determines if only the selected [Selected] vertices will be moved, vertices that are connected [Connected] or those vertices for which the edges between the selected vertices form a boundary loop [Region]. That last item comes with an additional option to select either the smaller or larger boundary region.

Select Bigger

Select either the smaller or larger boundary region.


These buttons offer a quick way to rotate the aligned vertices in 90° steps around the normal of the reference plane.


If checked vertices will be moved in such a way that the median point of the selected ones will be coplanar with the reference plane.

To centroid

If Snap is checked, checking To centroid will make sure that the median point of the selected vertices will coincide with the centroid.


The move tool moves selected geometry along the normal of the reference plane or along on of the references axes.

It behaves much like the grab tool in regular edits. As long as you move the mouse you keep moving the selected geometry until you hit ESC, or one of the mouse buttons.

Pressing Ctrl limits movements to fixed increments, while pressing Shift will make movement slower and more precise and entering a number will let you choose an exact displacement.

You can even switch to Scale or Rotate mode by pressing S or R respectively.

A small reminder is shown in the lower status area:

The available keystrokes are summarized in this table:

Key or mouse button



Toggle restrict movement to X-axis 


Toggle restrict movement to Y-axis 


Restrict movement to Normal 

Shift N

Restrict movement to XY-plane


Toggle distance calculation from relative to initial cursor to relative to centroid of reference plane and nice versa


Restrict movement to fixed increments


Reduce movement (more precision)

. (dot) - (minus) or any digit followed by Enter 

Enter a numerical distance

Esc or Left mouse or Right mouse

Leave Move mode


Switch to rotation mode


Switch to scale mode


The Rotate tool rotates the selected geometry around the normal of the reference plane or one of the other reference axes. Just like the move tool it allows for precise manipulation with the Shift and Ctrl keys as well as numerical input. For all available keystrokes see Move


The Scale tool scales the selected geometry along the normal of the reference plane or one of the other reference axes, with the centroid of the reference plane as the center of the scaling operation. Just like the move tool it allows for precise manipulation with the Shift and Ctrl keys as well as numerical input. For all available keystrokes see Move


The Duplicate tool duplicates the selected geometry and then starts the Move tool. It is a convenient shortcut that acts much like Shift-D does.

Snap centroid

Snap centroid moves the centroid of the reference plane to a new location without changing the orientation of the plane. It comes in two flavors: unconstrained and constrained.

A constrained snap will move the centroid as close as possible to the center of the selected geometry while making sure that the centroid will stay inside the current reference plane. So the plane will not move, just its center.

An unconstrained snap will simply move the centroid to the new location even if it is not within the plane. The orientation of the plane however will not change.


The Ortho add-on has several attributes that can be changed in its preferences. The color swatches allow you to change the color and transparency of the reference plane as well as the colors used for the normal and the reference axes.

Also, by default a keyboard shortcut is created for the Windows-Key + O (Or Cmd-Key + O) that will pop up the pie menu. If you would like to use a different shortcut you can disable the default one and create one yourself. See Can I change the default shortcut?

Can I change the default shortcut?

Yes you can: you can disable the default shortcut by selecting User preferences → Add-ons → Mesh → Ortho and then unchecking ‘Create OSKEY-O Shortcut’.

There is a helpful hint below those preferences that tells how to create a keyboard shortcut of your own choice:

Goto User preferences → Input → 3d View → Mesh

Click on ‘Add new’ and select a keyboard combo that you like (it must of course not be in use already). In the image below we have chosen the impossible to enter keyboard combination Shift-Ctrl-Alt-Cmd-A.  

For the operator identifier, use wm.call_menu_pie and for the Name use mesh.ortho_pie

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