Drinking glasses turning grey

[Sando]

Hi all,

Does anyone know why my glasses in the picture are turning grey as they are repeated?



I am using the standard v-ray material for glass. I have tried adjusting the material settings but nothing seems to work. Is it because of the mirror material behind them. The only time they work is when I render them on their own.

Cheers,
Sando

[dalomar_cg]

Re: Drinking glasses turning grey

Max Depth is what's cutting that off...Options> Global Switches. For a scene like this it should really be pretty high to get the best results (25 maybe) however, there's a huge jump in render time when adding that many potential bounces. For trials I'd put it around 8 so you can get a decent result, but not too long. See what 12-14 will get you, but you're probably going to have to go much higher to get better results.

[Sando]

Re: Drinking glasses turning grey

Thanks Damien. I'll give it a shop. This is only a small part of a larger image. The entire image is going to be rendered at A2 size so maybe I can get away with a lower value.

I'll post my finds.

Thanks again.

[Sando]

Re: Drinking glasses turning grey

Hi Damien,

I have been testing what you suggested and even though it works the render time is just too long. Is there any other ways to get around this "Cheat" perhaps?

Cheers,
Sando

[Micha_cg]

Re: Drinking glasses turning grey

After the image is rendered I would set the refl/refr depth at a high value and use _renderwindow to get the glasses clean. Or did you go this way?

[Sando]

Re: Drinking glasses turning grey

Hi Micha,

Yeah that is what I plan to do but the initial render for just the glasses within the image is taking a long time. When I mean a long time, it's take longer then 30mins to show any movement. I will do a normal render and like you say just render that small bit higher values over night and see what kind of time it's going to take.

Thanks for your help
Sando

[dalomar_cg]

Re: Drinking glasses turning grey

In the Options rollout of you're glass material, there's a value there called Cut Off, which determines when not to trace reflections and refractions (assuming there are enough bounce in Max Depth to get there). Try increasing that (.005 or .01) and that should speed things up a little bit while still getting decent results.

[Sando]

Re: Drinking glasses turning grey

In the end the entire image only took about 1.5hrs with the refl/refr setting at 25. I might even try higher value and adjust the cutoff like you mentioned if it becomes a problem.