Here is a basic description of how things will be converted:
vo requires a camera view to export. It should be exported pretty much correctly, but unfortunately the roll (or bank angle) will not be correct. This is not an issue for any scene where the camera has a look-at target.
(If your scenes lack cameras - shame on you! - you could try using a "view2cam" tSX to automatically create a camera view for you. One such tSX can be found at CK's site: http://tokyo.cool.ne.jp/cgf/tsx_e.html).
vo allows you to export each frame of an animation, just the current frame, or a sub-range. Animated materials will in most case be translated correctly, and vertex animation, bones and other deformations will also translate correctly.
This is the area where there is most difference between renderers, of course. vo will try to come up with the best VL shader for each tS material:
Glass, dielectric, and mirror shaders will result in VL shaders with caustics enabled.
It should be noted that the ambient value of a reflectance shader controls how emissive the surface is when rendering with irradiance enabled.
Color procedural shaders can be converted to texture maps that VL can render. Solid procedural shaders will not look exactly the same, for best results 2D (wrapped/UV) shaders should be used.
Transparency shaders are not fully supported in VL, however if your tS material has a transparency map, or plain transparency, that WILL be converted correctly.
Procedural rough and wrapped rough shaders will be converted to the closest approximation in VL, but it is recommended that regular bump maps are used.
The different shading types - faceted, auto-facet, and smooth shaded - are supported fully for polyhedra, but NURBS are only either totally smooth, or totally faceted. NURBS objects are also only exported with a single material.
You now also have the ability to use the "vomat" custom tS shader in your materials for the greatest control when creating surfaces for VL. A sample material library is included to get you started.
All polyhedra are exported as triangulated meshes, so there are no problems with polyhedra with holes, for example.
NURBS patches will be exported as NURBS patches, though vo does give you the option of converting to triangles in case the render is not as you expected.
Metaballs will be exported as VL blobby objects. There is a small difference in size/influence, but nothing major. Only sphere metaprims are supported.
Subdivision surfaces are not supported in VL, so they are just written as triangles.
The object render options "cast shadow" and "receive shadow" are fully supported.
This is another area that can differ wildly between different renderers. vo will attempt to convert tS lighting as accurately as possible:
Local, spot, and infinite lights are pretty straightforward.
Goniometric lights will be converted to spherical area lights.
Sky lights will be converted to a VL sky. Intensities lower than 1 are recommended.
Area lights will be converted to VL flat area lights, but the conversion is not always straightforward, due to differences in renderers and their representation in tS.
IBL lights will be converted to VL sky lights, but using the image you used in the IBL light. There are a couple of differences; VL has no concept of the IBL orientation, so rotating will make no difference. Related to that, you may also find that the image is not aligned exactly as it is in tS; you may need to edit the image in Photoshop or the like to make it fit.
If you enable lens flares for a tS local or goniometric lights, the VL light will have a visible glow. The size of the glow is specified by the size of the tS light object.
Shadows are either on or off; there are no shadow maps in VL.
VL has support for non-specular lights. This means that the light will still illuminate objects and cast shadows (if on), but won't cause a specular highlight to appear. It's useful for fill lights. To turn off specular highlights for a particular light, uncheck the tS option "Physically based untis for the light" (yes, it's a typo in tS)
Negative tS lights will be written out as VL blackholes
Projector lights are not supported at all
Not many of these will convert properly, but:
Background color is correctly exported
Gradient background is correctly exported
Background image is correctly exported
Enabling "Simple Volumetric" in tS will convert to participating media settings in VL. Only the Samples and Density parameters apply. Note that you still have to enable volumetrics for each light.
Fog (NOT ground fog) is supported