Go to http://support.chaosgroup.com and if you're not registered, do it. Go to VRay builds and download a build for you maya version. Installation should go without any problems because vray now offers new user-friendly installer.

After succesful installation you have to enable vray plug-in in your maya settings by going to Windows --> Settings/Prefferences --> Plug-in Manager, scroll down for vrayformayaxx.mll and check 'Loaded'. Check also Autoload if you want to start vray every maya initialisation.

If you open HyperShade you'll see there'a a new Node called VRay Mtl. This node is recommended to use with vray because it's optimized for vray. However vray supports some maya nodes but speed of rendering while using them can dramatically slow down. As you can see on the image below, the time using lambert and vray mtl are exactly the same until there are no extra effects like transparency, refcetions etc...

Now i'll show you how to setup HDRI using vray4maya. There are two ways to do this. First method adds only reflcentions, no extra lighting, no extra render time. Setting this is very simple. Go to vray render setting, under Environments --> Override Enviroments --> Reflection Texture to put your hdri image.

Second way is by using VRAY Dome Light. Put Texture into DomeTexture Slot and check 'Use Dome Tex'

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Now if you take a look at the rendered images you'll se there's a huge difference between these two images. First method generates only reflections with low render time. Second gives us nice soft and smooth shadows and the same reflections as preciously but render time is several times bigger.

Here a quick overview of a VRAY Sun system which is real-life system. In my opinion vray sun is a little bit faster and more accurate than mental ray's. To enable sun system, go to Render settings --> VRay Sky. Below is a little comparision of vray and mental ray sun system.

Now i'm gonna present 2d texture called vraydirtmap provided with vray. VRAY Dirt Texture map is used to generate occlusion map. On the image below, you can see how to connet VRAYDirt node to shader. VrayDirt node gives really good effect but it's not fast as mental ray's Mia_occl_map.

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Now take a took at bump and displacement. Bump map works like in any other renderengine, just by connecting bumpmap (Mayatexturenode) with bump slot you gain nice bump effect.

... but where's displament slot?
It's a little bit tricky, while there's no place to connect this map, you need to put this directly into Shading Group. Take a look at the image below to see how to do this. Also, there are some advanced displacement options under Render settings.

SSS is a part of VRAY Mtl allowing you simply and fast gain wax or skin like effect. Until it's not a 'physical' material, your renders should go quickly:) :-)

Take a look at the setting in attreditor, there are not some many setting to play with, all you gotta do is set some refraction, fog clr and it's intensity and scatter coefficient. This SSS Material is far behind MentalRay's SSS Materials but it should be good for vizualisations arch, e.g for candles and thing like that.

VRAY Rendering Engine for Maya also provides it's own light nodes. There are two ways to create them: First is Create --> Lights Second is HyperShade.

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Below there're few images showing you vray lights. All light produce nice smooth and soft shadows (depending on subdivs value).

Now let's take a look at render settings

Global Illumination

VRAY Engine calculates global illumination using two gi engine. You can play with IrrradianceMap, PhotonMap, BruteForce(QMC) or light cache. It means, you can choose any of this method in that two slots.

IrrMap as first engine and light cache as second - this is universal method of gaining a good GI, but if you are a mentalray user you'll probably say, where's the f... photon setting, no worry, if you choose PhotonMap as your secondary engine, you'll have ability to control number of traced photons. There's also photon subdivs value in light setting.

Antialiasing

Under Image Sampler you'll probably find AA Settings. There are seven AA filter. People say that the CatmullRom can produce best results for viz. Play with this settings and chose best for you.

Quality

There's one fast way to increase quality and render time. Under DMC Sampler rollout, there's SubdivsMult, what it does? Increasing this value, affects all subdivs values in dof, motionblur, irradiance map, brute-force GI, area lights, area shadows, glossy reflections/refractions... let's thinking about it :-)

Wish you success and enjoyable with Vray for Maya 2008 plugin !