Overlapping cubes are OK

A straightforward question coming from people who are used to polygon modelers like Sketchup is how to make a large box in Tinkercad. A simple solution is to select a smaller rectangular tool shape and craft the bigger box using it.

  

Because Tinkercad is a solid modeler the resulting STL file will have no internal geometry, all the crafting operations are fused together to form the object. More generally, only the final shape matters when printing, the way it was created doesn’t affect the printer output.