Is there a shortcut to turn snapping on and off?

There are no "snapping" options in SketchUp as there are in some other 3D applications. Rather SketchUp streamlines the modeling process by using one system, its inference engine, to determine where geometry is positioned in space.

Unlike in many of the other programs, SketchUp is a real-time renderer, which models in a truly 3D, virtual environment at all times. There is no option to fix a standard camera view, like Top View, and disable orbiting. The camera position is just a temporary view that you may have chosen as the ability to orbit is always present. Without some way to infer where stuff goes, when you click on some point on the screen, that point may be anywhere from the end of your nose to Alpha Centaur.

So it would be hard (to put it mildly) for SketchUp to position anything with just the mouse.

Those are the tradeoffs to making a real-time-renderer easy to use.

the 'official' stance on SketchUp's inference system:

When I use the term "inference" I am referring to the process in SketchUp whereby an algorithm takes as input a 2D point on the screen (the point under the mouse) and 'infers' from it the most likely intended geometric point in the 3D space of the model.

Inferencing cannot be turned off in SketchUp because without it SketchUp cannot determine where points should be located in 3D space. This is different from the 'snap' systems found in other CAD systems in several key ways. Most importantly, geometric inference in SketchUp means you don't have to be explicit about 'working planes' at any time. You just draw and (usually) it just works.

In implementation, SketchUp's inference system like an auto-correcting spell-checker on your smart phone. It can give the wrong answer, but it usually gives the right one. As you learn how to rely on the system, it begins to give you the right answer more and more often. And your work speeds up.

I've watched many people learn SketchUp over the years, and issues around inferencing come up over and over. In every case, they come from folks with loads of experience in some other tool, either one of the big DCC apps (Max, Maya, SoftImage) or a 2D drafting system (AutoCAD). The most useful advice I can offer is that SketchUp is different... but not wrong.

If you're able to relax into the inferencer a bit, you'll find it rewarding. If not, it will be a constant source of annoyance that will ultimately cause you to go back to whatever tool you were using before.

But it just can't be turned off without rethinking the entirety of SketchUp's core tool set.

john bacus

Project Manager

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(ps: Zooming in or changing the point of view in some other way almost always resolves ambiguity in the inferencer. Remember - you're working in 3D all the time, so changing the camera position can be done constantly and fluidly.)

Consider mastering SketchUp's inference a rite of passage. Positioning geometry without constraining it on axes / edges / perpendicular to / on faces / parallel to etc or inferencing with other geometry, with a mouse click or just an extra value input, would be impossible. Snapping to is an indivisible part of it. Instead of fighting it, take advantage of constraining and the inferencing engine in SketchUp.

Tips For mastering SketchUp inference engine and snapping.

Plugins Several different plug-ins may help drawing and moving geometry in specific situations.