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Apart from documentation included with the AppSDK and this guide, the help pages for 3dsMax and Maya on docs.chaosgroup.com are a good source of parameter information and examples, although they use the user-friendly UI names for things and not the actual scene parameter names.
A very useful tool for basic parameter information is plgparams.exe included in the binary folder of the SDK. It lists all parameters for the specified plugin (or all plugins with -list) and their types, default values and text comments. Similar information can be obtained using the ListAllPluginsAndProperties example in the C++ folder (or equivalent code for another language).
It is often useful to save out your scene to a file to inspect if you did everything properly. For example you may have failed to set some parameter properly and you will see this in the file, although you can also check the result of the set operation in your code. You can try to pinpoint problems by deleting parts of the scene (parameters or whole plugins) and re-rendering.
It can be very helpful if you have a V-Ray for 3dsMax or Maya and use it to export vrscene files to see what plugins and parameters are written out. The exporters for 3dsMax and Maya can be considered "ground truth" (even though they may have an occasional bug or missing feature).
If you're getting a black render make sure your camera is positioned and oriented properly and not inside an object. Keep in mind the default up-axis is Z, but it can be set to something else, usually Y. You might also get invisible or black objects if something is wrong with the attached material.
Another thing to watch out for is V-Ray's errors and warnings, so always implement the DumpMessage callback.

1.7. "subdiv" parameters

Note

2. Defining camera position

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6.6. Physical camera

6.7. Color mapping

6.8. Stereo and panorama rendering

For stereo rendering you need to add a VRayStereoscopicSettings plugin to the scene (if there wasn't one already). It's recommended to change the focus_method parameter to 1 for panorama or 2 for normal camera. The rest of the default parameters should be ok.

If you're doing this on the GPU, don't create VRayStereoscopicSettings and just set SettingsRTEngine::stereo_mode=1 (boolean) and SettingsRTEngine::stereo_focus as you would set VRayStereoscopicSettings::focus_method.

Also remember to set a double horizontal resolution for stereo. So if your normal render resolution is 640x480, make that 640x960. The left half of the image will be the left eye view and the right half is the right eye.

For spherical panorama rendering you need to:

• Change the type parameter of SettingsCamera to 9.
• Set the field of view to 360 degrees or rather 2*pi, because the fov parameter is in radians. You need to do this with the RenderView plugin and with SettingsCamera - both have an fov parameter. Also if you're using PhysicalCamera with specify_fov=1, set fov there too.
• Set the vertical field of view to 180 degrees. This may be a bit confusing: it is set through the height parameter of SettingsCamera. Also the value is not in radians, but in degrees.

For cubic (6x1) panorama rendering you need to:

• Change the type parameter of SettingsCamera to 10.
• Set a resolution with aspect ratio 6:1 or 12:1 if you are doing stereo. So for a stereo cubic panorama with 1000x1000 pixel cube sides you will render at 12000x1000.

6.9. Miscellaneous

The SettingsRaycaster plugin has one parameter of interest: embreeUse. You'd want to set this to 1 (default is 0), because it increases raytracing performance.

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