I am relatively new to Poser, but I am not happy with the results of images rendered in Poser. I want a very realistically rendered sharp image like the ones obtained by using VRay. So my question is this, can I use VRay to render objects/characters created in Poser? If yes, please explain to me how. If not, then could you please suggest another Rendering Software which can be used with Poser and give very realistic results. Thank you so much.

P.S. The reason i don't like Poser rendered images is because they give blurred edges on the light shadow transition, unless I use very high intensity light. I want a very "crisp" transition from light to shadow even with normal intensity light. Is there a setting in Poser which will enable me to get these kind of renders? If this can be done in Poser then I won't need a seperate rendering software. (see this image to get an idea of what I mean http://www.2ql.net/uploads/1254629088.jpg )

go to the window with your dials. Select the other tab, and uncheck 'smooth polygons', and see if that helps. I only have P5, so there's 3 other versions past that...don't have Poser up at the moment, or I'd be more specific. hope this helps.

In the settings for the light that is casting the shadows check the Shadow blur radius setting. 

I get quite sharp shadows using a setting of 2
multiple lights will of course affect how crisp the shadows are .

you can also check that the shadow camera is covering only your scene, too big an area, too low a resolution on the shadow map and you get fuzzy shadows.

You can also switch to ray traced shadows.

Also make sure your shadow color is set to black

"pakled": I never use the "smooth polygons" option so it is always unchecked.

"markschum": What you are talking about is CAST shadows. What I'm talking about is the the shadowy part of the object itself. Like if you have a sphere and there's only one light source from the left hand side, then the right part of the sphere will be in darkness. Now in the middle of the sphere, where the transition from light to shade happens, the light and dark areas will be merged in a blur. I want a crisp line seperating the two areas.

Thank you both for your suggestions, but I'm starting to get the feeling that the effect that I am looking for cannot be achieved with Poser's rendering engine. So can anyone suggest a really good Rendering software which is compatible with Poser? i.e. I should be able to export Poser objects and import them into the Rendering Software.

I don't know of any rendering engine that can be incorporated into poser, per se.  Carrara is supposed to be able to import poser objects, characters and scenes. 
I usually export Poser stuff as obj's and import them into trueSpace.   The only downside to that is that transparencies don't transfer.  I have to redo any transparencies. So, I'm betting you could do that.

"really good" is going to be subject to opinions; a non-exhaustive list:

Poser scene file import

Vue -> direct import
Carrara -> direct import
Daz Studio -> direct import
Cinema 4D -> import via Plugin
POVRay -> immport via PoseRay
Kerkythea -> import via PoseRay

The degree to which Poser features are supported on import varies - Google or Bing away for specifics. The vast majority of apps probably support importing .obj format. I wouldn't be too quick to conclude that Poser can't do it though.

 Well it's mostly a question of light and the right materials.

It's not TOO hard to get a toon appearance in Poser

There are lots of toon shaders available if you're not sure how to do them yourself.

I made a VERY basic pack back in the Poser 5 days - it's rather crappy by today's standards, but you could look at it asd a starting point :)

azi,

The transition between lit and not-lit reflectance (called the terminator) is decided by the algorithm used for Diffuse reflections. In Poser, the default built-in calculation is the Lambertian reflectance model. There is another model called Oren-Nayer, implemented in the Poser Clay node. This has a roughness parameter that can somewhat sharpen the terminator.

But you've used the word "realism" and then described a behavior that is decidedly unrealistic.

I have tested the reflectance of paper and it is exactly reproduced by Poser's Diffuse node. So asking it to do anything different is asking for non-realism.

The reason the light fades as the angle changes is a simple consequence of the geometry of the situation. Imagine tracking millions of photons that are 1 micron apart, approaching a surface perpendicularly to the light path.  These photons will strike the surface with a spacing of 1 micron, so you'll have 1 million photons per linear meter.

Now change the angle so that they approach at a 45 degree angle. The photons striking the surface will land 1.414 microns apart. resulting in only about 707000 photons per linear meter and the surface will appear darker. At an approach angle of 1 degree, the photons land about 57 microns apart, or 17000 per meter, resulting in the surface being only 1.7% as bright as the 90 degree case.

oh. Well, I'm using a very old (Steam-powered) version of Poser...;) P5...;)