Is it possible to convert a Las /Laz file into an STL or OBJ file?
Given that LAS/LAZ is LiDAR point cloud data, there is a GIS tool called las2tin to convert these files to a triangle based mesh called Triangular irregular networks or TIN by the GIS community. Other GIS tools should be able to do the same, for example ArcGIS.

Once you have the mesh, Google should be able to help you find a way to convert the TIN to an STL. You will need to scale down the STL after creation, as the TIN will probably be at 100% scale.

One example workflow for converting LAS data into an STL is:


Using ArcScene: open DEM > convert to TIN > export to VRML
Using MeshLab: open VRML > export to STL
Using Meshmixer: extrude base > scale to fit standard printing parameters > save as finished STL


More details for the process that I got from Google are available here