As students progress with their work, the program begins to slow down and not allow additions to their project. In many instances, it will not save their work.
This can be an issue when files get to be large. Autosaves will take longer and Depending on the operating system (SketchUp for Schools is not an operating system, by the way) and the device’s available memory as well as GPU, they can contribute to sluggishness. Teach the students how to purge unused components and materials from their models and recommend that they do that regularly to keep the models under control. Also, if they are allowed to add components from the 3D Warehouse, instruct them in how to search for and use lower-poly components. There are a lot of components that are just too “heavy” to used projects, especially with web-based versions of SketchUp. Properly managing their models will be the first step in improving performance.
As usual you beat me to it DaveR and also as usual, you are 100% correct. Smart modeling practices make SketchUp run a lot smoother.
If I intend to make a large project I try and limit myself to as few polygons as possible and as few textures as I can. Sometimes I’ll even optimize items from the 3D Warehouse a bit to make them even more efficient before I import them into my model. Just a few polygons can make a big difference if they are applied to a component that repeats many times.
If one of your students is willing to share an example file with you to share with us we might be able to give you a few ideas on where to look for those small optimizations.
Finally, if you are using the web version, make sure to refresh the page every few hours. It does not do a lot, but every little bit helps!