Interface faces with model/selection

[RogerS]

What's the difference between the two and when would you use one rather than the other? Googling "Interface faces with model" comes up witha result but I can';t find one for 'with selection'.

 

[cambournepete]

I don't understand what you're actually trying to look for ...
<edit ... didn't realise it was a ketchup question >

 

[SketchUp Guru]

I think you mean Intersect Faces with Model and Intersect Faces with Selection. Intersecting with the Model results in intersections where where ever the geometry is touch other entities. Intersect Selection is more precise because intersections are created only between faces that are actually selected. I rarely use With Model because I always want to control what intersections are created and I don't want to add a bunch of needless lines.