Align Edge With Vertex

 SimuSEM Tutorial:  Align the edge of one shape with a vertex of another shape

This tutorial makes use of Blender’s Pie Menus and Edit Mode.  A Pie Menu is a menu in which the options are spread out in a circle around the mouse pointer.

Edit Mode in Blender allows you to select and/or edit parts of a shape.  In this tutorial, Edit Mode is used to select the edge of the shape that you want to align.  Use Edit mode carefully because you can easily deform a shape such that it will not simulate properly.  With some limitations, custom shapes can be created in Edit mode, but that is not the topic of this tutorial.

For this tutorial, we will align the center of the bottom edge of the purple block with a vertex on the turquoise block\

1. Switch to Edit mode, select the edge you want to align..
• Start by selecting the object that you want to move.(the purple block)
• Switch to Edit Mode
• Choose the middle button to the right of “Edit Mode” (as shown in the figure), which allows you to choose an edge.  Then click on the correct edge.  (The first button lets you choose a vertex and the third, a face.) 

2. Press Shift+S to open a pie menu and choose Cursor to Selected (bottom)

• If you want to align the object to a location on an edge that is not the middle or the end, subdivide the edge to get a vertex in the desired location before choosing Cursor to Selected.  Use Vertex --Subdivide in the top 3D View menu.  The subdivide menu will appear in the lower left corner of the 3D View, and it may be collapsed.
2. Switch back to Object Mode 
3. Right click on the object–Set Origin–Origin to 3d Cursor.  This sets the object’s origin to the edge that you want to align
4. Now move the 3d cursor to the vertex of the other shape
• Turn on Snap to Vertex in the top menu bar.
• Choose the 3d cursor on the toolbar on the left and click on the vertex of the block to place the 3d cursor on the location that you would like to align.  If you click near the vertex, the cursor will snap to it.  It is sometimes difficult to choose a 3d location on a 2d screen, so you should rotate the view to make sure the 3d cursor is at the correct location

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• After moving the 3d cursor, choose either Select Box or Move in the toolbar on the left or you risk moving the cursor somewhere else.

6. Make sure the purple block is still selected.  Press Shift+S to open the pie menu again and choose Selection to Cursor (top).  The edge of the purple block will now be aligned with the corner of the turquoise block.
7. You may want to move the origin of the purple block back to the center.  To do that, choose Set Origin–Origin to Geometry in either the right mouse button menu or the Object menu in the 3D View.