VRay RT Beginner Questions/Problems

[H3rb13]

Hey guys,

I have tried to find some answers for some questions I have regarding VRay RT (in this case for Max2011) on Google, but could'nt find any. So, I hope there are some pros here who can help me out.

1)
I always get a "grainy" picture (please see attached image below) when rendering previews or using VRay RT as Production Renderer. I have tried different light settings to no avail.
What is the reason for the "dots" in the image? I assume it is the lighting but maybe somebody has an idea about what needs to be done to reduce the noise in the images.

2)
When rendering a movie it takes ages. I have some chrome and other reflective materials in the scene, but overall no high-poly geometry. Is there something I can do to reduce the rendertime? Or are there other reasons than the previously mentioned that might cause this?

3)
Do you know any websites that offer some good VRay RT beginner tutorials, regarding lighting for animations (not stills!), VRay camera usage etc.?

That's it for now folks. Maybe somebody can help me on this or point me in the right direction.

Cheers!

[super gnu]

hi H3rb13.. the problems you are describing are due to the fact vray RT isnt designed as a production renderer.. i think vlado only gave us the option to save out images with it because people pestered him.. its mean for previz.. setting up the scene. full blown vray is much better for producing good quality output.

however it sounds very much to me that you are simply not giving RT enough time to clean up the images before saving. since RT progressively reduces grain, you need to set a time limit for it to spend on each frame.. give it longer, and it will give you less grain.

to get clean renders though, your still MILES better to use standard vray, itll do it 10x faster.

[Alan Iglesias]

Some answers...

1). The "dots" you see are simply noise. RT uses Progressive Path Tracing (PPT) which is straight-ahead V-Ray rendering without the bias controls. You might be more familiar with the term "Brute Force". It means basically that RT is progressively creating your rendering using no tricks like Irradiance Mapping or Light Cache, which take set-up time and takes away from the immediacy of Real-Time rendering. If you have excessive noise in your shot it simply means that RT meeds more time and/or processing power to get it to a point that is acceptable for your particular application.

2). It sounds like you are using RT with processors that are not up to rendering your scene as quickly as you might like. Remember that this whole RT thing is brand-new and really represents in some ways the future of 3D rendering, so things are changing rapidly as we speak. Currently, RT is used by most folks as a way to quickly preview lighting, materials, reflections, GI and such but these folks are typically using bias controls for final production rendering. On the other hand, there are more than a few who have outfitted their system(s) with the latest in GPU technology and are able to render noise-free frames very quickly, depending on the scene. I have actually delivered stills and animations rendered in RT/GPU, but they were fairly simple scenes compared to a lot of the huge Arch/Vis projects that many of us are doing at times. But it was in fact production frames delivered with RT nonetheless, and very quickly I might add!

3) RT-wise, I would recommend reading all the messages in these V-Ray RT-oriented forums, from start to finish, taking notes as you go. There is a wealth of information here, not only from many of the very first users of V-Ray RT, but also from the head of development as well. This information documents the time from the very first beta releases of RT to the present, so there is probably more information here than anywhere else. As far as the rest of V-Ray, a simple search will show hundreds of sites that offer V-Ray tutorials, both for free as well as ones you can buy. There is even stuff on YouTube that is very helpful. And don't forget these forums (search on any subject) AND the V-Ray help database (http://www.spot3d.com/vray/help/200R1/) which has many helpful tutorials, especially on how to properly render animations.

My best of luck to you, and happy reading and rendering!

-Alan

[H3rb13]

First of all sorry for the late reply. I had hoped to use the RT as a production renderer because I used to do lots of projects in RT engines, including the rendering. I just wanted to combine the power of 3DsMax regarding animation with the swiftness of a realtime renderer.

Anyway, thanks for all your help, will do as you guys said. Maybe VRay RT rendering for production will be possible one day without "dots"...in the end time's money...

Cheers,

Herbie