sketchUcation

Activate the tool via Tools->RakeAndSplay.
Click on a model location where you would like to create the helper geometry.
A dialog box will appear in which you enter the rake angle, splay angle, size of the planes, and segments for the follow-me circle.
When you click OK, several layers with names starting "R&S" will be added to your model if they do not already exist (some of the layers are hidden by default).
The Tool create a Group to contain new geometry. It will draw Construction Lines along key axes of the leg/joint. It will also draw Faces in the rake plane, splay plane, miter plane, follow-me circle plane (orthogonal to the leg/joint axis), and sighting plane. These axes and Faces help you to visualize the geometry of your leg/joint and to draw the parts. After a Group is drawn, if you click it with the Tool active, a dialog will display calculated angle values for axis tilt, sighting axis, rake miter angle, splay miter angle, and bevel angle.

Following installation, detailed discussion of this Tool is contained in the "RakeAndSplay/Rake And Splay SketchUp Plugin.html" file in the Plugins folder.

Version 0.1: Initial release June 2014 Version 0.2: Changed so that height input is height from floor to chair seat (or height of box). Version 0.3: Added leg vs box type for more helpful placement of rake and splay planes.