Newbie with light questions and render time

[redynvre]

Hello All,

I am trying to learn and understand Vray with a quick 3D model of a bottle. I followed the manual for renderings and odd things happens:
- When I turn off all the lights like suggested in the manual to have a black image, I get the attached rendering. If I turn off the shadows, they still show up in the render.
- Also, regarding render time: When the bottle is opaque it renders fast. But when the bottle is more transparent, but not fully, the rendering time slows down to a crawl, meaning 3/4 of an hour. I am not sure what is going on. The PC is a dual pro, with a 512MB video card, and 4G of Ram.

Thanks![img][/img]

[dalomar_cg]

Re: Newbie with light questions and render time

It is important to download the scenes that accompany the manual and start with those. The manual starts from our old defaults, which are significantly different from the new ones (the new defaults have the physical camera and sun/sky which throws off the startpoint of the manual significantly). I've attached the old defaults, so if you don't start from the actual manual files you can at least load those an be in pretty decent shape.

The reason why things take so long has to do with the sun and transparency. The sun, when its really bright like you have in your image, will cause v-ray to take a longer time calculating the image (this actually goes for all lighting, but it has a tendency to happen more with the sun) so making sure you have the right illumination levels is important for speedy renderings. Transparency will also cause more rays to be traced, which typically isn't too much of a problem, but put that together with the bright light and things will start to take longer. Also if that transparency was set through a Rhino material as opposed to a v-ray one, that might take longer to calculate as well (rhino materials are typically fine, but transparency doesn't work nearly as well within a Rhino material as it does within a v-ray material)

[redynvre]

Re: Newbie with light questions and render time

Thank you very much for your help! I will try all this and see how it goes

[redynvre]

Re: Newbie with light questions and render time

When I try to load the old default settings I just downloaded I get an error message that says: Failed to load settings. The file has been put in the option file where all the other settings are located. Might the file be corrupted?

Also: is there somewhere a book or a website that explains all the terminologies used in render option? They are all so obsure to me, and when I try to modify them to see what they do, well, they do nothing or very little, as most of the time my rendering stays unchanged.

I have done a lot of 3D modeling work over the years, but it is only very recently that I actually have to render it, and I know nothing about it.

[dalomar_cg]

Re: Newbie with light questions and render time

Sorry about that...I keep forgetting that some of the things within the development builds can be used by the released versions...the attached visopt should work fine.

As far as a good resource for terminology, the best is really www.spot3d.com . that is the official V-Ray for Max help site, which goes through almost every setting and explains what each one does and the range of inputs. It is for max, so some of the settings may look different, but functionally they are all the same. Also, the newest version of vfMax changed a few small peices of terminology, so any place you see DMC or Brute Force, that basically means QMC on our end.

[redynvre]

Re: Newbie with light questions and render time

Thanks the infos! OK, I tried rendering with the updated "old default" file, and now, after 4 passes, I end up with a white rectangle that is 1681x973 in resolution instead of my bottle. I have not changed any settings whatsoever.

[dalomar_cg]

Re: Newbie with light questions and render time

Well, the resolution thing is because the viewport resolution isn't overriden in those settings I gave you (check the Output rollout). As for everything being white, chances are that the default light is still on, or that I possibly left GI and/or the sky on. Disable the default light (in global switches rollout) and make sure neither GI or Background have a map on them (denoted by a capital M...in the environment rollout).