Jaxilon,
Silo is indeed stand-alone. It can export to several formats, one of which is bound to work with whatever renderer you're interested in using. OBJ, DXF, POV, and some others. It'll even save in STL format...just in case you want to maybe convert your virtual object into a real one! Now, truthfully, I usually have to flip polys, correct scale, and so on following a Silo export but I think that happens with just about any 3D app...they just don't work and play well together most of the time. I've never tried it but POV is the format for the free POVRay renderer. I used to play with that quite a bit back in 1990-1992, when it was script only. Never tried it since it has advanced but I expect it's quite good.
M