If you are looking for component/framework that will be able to render the STL file (commonly used in 3D printing) directly I don't think you will have much luck for that in gaming engines. Main reason for this is that STL file format only holds geometry information but no information about surface color, surface texture, or even surface material (useful in determining surface shading effects). And because graphics card actually needs that additional data commonly used formats by game engines already store it along with 3D model information for ease of use.

But perhaps some of the 3D graphical engine developers might be willing to try and add support for importing a STL file format to their graphical engine in order to render it.

Another solution might be to simply find a converter that is capable of converting STL format to some other 3D mesh format.

And if you are more interested in designing of these 3D boxes then my best solution would be to use any 3D designing component/program and just find a suitable converter that can convert from any of the supported format from 3D designer to one of the supported format by your laser cutter.