How do I remove gaps between two wavefront OBJ layers? I have generated two wavefront OBJ layers - a terrain surface from GeoTIFF to TIN to OBJ and some buildings from shapefile to extruded shape to OBJ - using Safe Software's FME.  In the FME previewer the two layers sit flush but when I import to Blender (2.78a on Windows 7 64bit) and render a scene the buildings are floating above the surface.

In the image below you can see the odd white line above the black hole of the building footprint.  I also created a single OBJ file by combining the surface and the buildings and embedded the buildings into the surface by offsetting in the Z axis by -1m. The problem persists in Blender.

Is there anything I can do within Blender to move the buildings into position?
The imported OBJ files were projected to the British National Grid (EPSG:27700) and as a result they were located very far from the origin. So, selecting the layer and setting Origin to Geometry and then updating the Location to (0,0,0) results in the buildings sitting flush on the surface.



Thanks to suggestions from batFINGER