Following the Inference Engine

SketchUp has an invisible inference engine to help you draw accurate and realistic models. The inference engine locates or infers points from other points in your model, such as the center of a circle, the midpoint of a line, a line that is perpendicular to the ground plane, a point on a face, a point on an edge, and so on.

SketchUp notifies you of these points by using both color indicators and tool tips, which are on-screen messages indicating the location of the cursor as you draw an entity. For example, SketchUp displays the string “On Face" when the cursor is touching a face. The following image contains five common inference tool tips. 

 

Additional information on the inference engine, including inference types, is in the User Interface section of this guide.

The first step to drawing in SketchUp is to learn how to draw accurately by following the cues of the inference engine. Simply select the Line Tool (it looks like a pencil in the toolbar) and start drawing. Pay attention to the on-screen tool tips from the inference engine as you draw. Most everything you will create in SketchUp can be created by inference using the Line Tool.