Vray Rhino - Small to Large Renderings

[timmylee]

Hello,

 

I am currently using Vray 1.5 with Rhino 5. I am a bit perplexed as to why I can easily render an image of 1000 x 750 in about half an hour. If I keep the same setting but increase the size to 3000 x 2250 it will take 20 hours. Logic would say that a rendering 3 times the size of one that takes half and hour would take 3 times as long to render (1.5 hours).

 

Does anyone know why the render time is increasing exponentially and if there is something I can tweak to correct this?

 

Thank you in advance.

[shauncarollo]

Hello,

 

I am currently using Vray 1.5 with Rhino 5. I am a bit perplexed as to why I can easily render an image of 1000 x 750 in about half an hour. If I keep the same setting but increase the size to 3000 x 2250 it will take 20 hours. Logic would say that a rendering 3 times the size of one that takes half and hour would take 3 times as long to render (1.5 hours).

 

Does anyone know why the render time is increasing exponentially and if there is something I can tweak to correct this?

 

Thank you in advance.

 

Well, actually if you increase the size along one side by a factor of 3, as well as 3 in the opposite axis, that is squaring the amount of area. So it actually is exponentially increasing the time required to render.

[senadgvozden]

I'm having the same issue.

 

Can it really be true that the render time increases exponentially? In 3Ds max a similar shot would take a fourth of the time, with the same settings and resolution.

[Tommy L]

Some light calculations are render size dependent (IR map for example). Your render time can be adversely affected by AA at different resolutions.

And the 1k going to 3k render is actually 9 x larger. See below:

1000 x 750 = 750,000

3000 x 2250 = 6,750,000

750,000 / 6,750,000 = 9

[Dimitris Tolios]

Tom gave it to you on the platter...

You did not increase the resolution 3 times...you did it 3 times "each side"...thus 3x3 = 9 times more pixels.

If you had done a 4000p wide images with same aspect ratio it would be 16x the pixels etc etc.

 

Also, keep in mind that as the resolution increases, certain settings in the irradiance map can be "loosened" to speed up the process without losing quality, as interpolation between light cache and irradiance maps works more efficiently.

 

EDIT: just saw when the OP was started...= fail