SketchUp
Exporting obj Files From Google SketchUp Pro
When exporting models as quads, faces with more than 4 vertices should be subdivided using the Line Tool in SketchUp to reduce number of vertices.
In the following example the original face included 6 vertices and was subdivided into 3 different quads.



The original face includes 6 vertices subdivision of the face into 3 quads final subdivided model
Select the faces you wish to export. From the File menu choose Export > 3D Model.
Set the output type to Obj and click on the options button to set Export Options.

Obj export options in SketchUp Quadrangular Mesh Loaded in GEM
When exporting the model as triangles, select the faces you whish to export and toggle the 'Triangle all faces' option from the OBJ Export Options.

Obj export options in SketchUp Triangular Mesh Loaded in GEM
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