Most 3D software permit to export under formats different from their source format. there is not a limitative list. For the objects, it is just a question of compatibility of the formats. In Vue, you can import a object  whose format is  : DXF or OBJ, 3DS, LWO, SHD; COB, 3DMF, WRL, PZ3 and PZZ, and DEM (only for Terrains). For example, You can use Onyx tree because with this software you can export the trees notably as OBJ objects.

Radiosity is not a software, but a category of lighting.

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