# How do you rotate an object so that a particular face is parallel to the ground?

How would I make the face of an object parallel to the ground? I could just eyeball it and use the rotate tool, but it probably wouldn't be perfectly flat. Is there a way I could possibly snap the face of the object I want level to the top of a block (making it parallel with the block) and then delete the block?

• do you want to rotate the whole object or only some faces? – josh sanfelici Jun 29 '16 at 16:51
• The whole object.. – Calvin Gozé Jun 29 '16 at 16:52

Not sure if there is a more efficient way to do this but the method I most frequently use is through an auxiliary empty object to snap to the surface.

1. Add a Plain Axis Empty to your scene
2. Activate Snapping and Align rotation with the Snapping Target
3. Align the empty with the part of the surface that is to become the base
4. Now you will have to manually copy the three axis rotation from the empty to the object inverting them. That means if your empty's rotation is 10,50,30 you will have to paste in your target object -10,-50,-30
5. Apply the rotation to your object
6. Adjust it accordingly to fix the orientation by rotating 180º in needed axis.

Side note: It is usually helpful if your "flat face" that is to aligned to the ground is slightly subdivided so there's a few extra vertex for Blender to snap to.

• Once the empty is 'stuck' to the face, you can parent your object with the empty. Then, simply clear the rotation (alt R). This avoid to copy/paste the rotation values. Then on the object, alt+P and clear and keep transform – lemon Jun 29 '16 at 17:27
• Nice one, hadn't though of that. Good tip, thanks! – Duarte Farrajota Ramos Jun 29 '16 at 17:31

If you don't mind installing an addon, Zaloopok made some personal tools which include a button called 'put on' that does exactly what you expect. You can find the help here and watch a video of the "put on" in action here.

A very simple way is to rotate the whole object by hand until it's close to parallel, then select all the vertices (in edit mode) that sould be parallel to the ground, and scale them to 0 relative to the Z axis.

• That could be considered "cheating". This is for 3D printing purposes I think, so doing that will alter the shape of the object and yield uneven joints that won't properly fit together once the object is assembled together – Duarte Farrajota Ramos Jun 29 '16 at 17:14
• yes, it depends by the use you need – josh sanfelici Jun 29 '16 at 17:18