Vray Rhino Rendering Time

[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.

[Smile of Fury]

Hi Timmy,

 

I think most of the answer is that the 3000 x 2250 is actually 9 times larger than the 1000 x 750 when you count the pixels, which is what matters. It's 3x bigger in X and Y, so 3^2 bigger.

 

This means that GI passes like Irradiance Map and Brute Force are also increasing in size 9x from the original.

 

If you post your settings someone here might be able to tell you what could be adjusted.

 

Also, did you fully render it out for 20 hours, or is that just the estimate? If the first buckets to render are something difficult, like glass, water, reflections, etc, then the estimate will be based on the CPU thinking the whole scene is that time intensive. Once the buckets go over the easier parts like flat diffuse colors or empty background the estimate will come down a little.

[timmylee]

Hello Ben,

 

Thanks for the response. I've included a copy of the rendering settings I am using. Please let me know what you think. The settings are set for a 1000 x 772 pixel rendering and the only thing I change for the large one is the output size (3300 x 2549).

 

As far as your question about whether I am letting it fully render or not I can tell you that I have. It does hang up more when it is rendering glass but the entire scene took 20 hours to do.

 

I should also mention that I tried rendering to VRImage files as I heard this worked better for larger renderings but it did not speed things up at all.

 

I am also using vrmap files for both the Irradiance Map and Light Cache. I believe that this speeds things up a bit.

 

Please let me know what I could change in my settings to correct this.

 

Thanks again.

 

Settings Vray 1.5 | Rhino 5:

 

Image Sampler-

 

Adaptive DMC

Min subdivs 1

Max subdivs 4

 

DMC Sampler-

Adaptive amount .85

Noise Threshold .05

 

Color Mapping-

Exponential

Dark Multiplier 1.0

Bright Multiplier 1.0

Gamma 2.2

Input Gamma 2.2

 

Indirect Illumination-

 

On

GI caustics (Only Refractive Checked)

Saturation .8

Contrast Base .5

Contrast 1.0

Ambient Occlusion On

Amount .8

Subdiv 8

Radius 10

Primary Bounces 1.0 Irradiance Map

Secondary Bounces 1.0 Light Cache

 

Irradiance Map-

Min Rate -5

Max Rate -2

HSph. subdivs 50

Interp. samples 20

Clr Thresh .4

Nrm Thresh .3

Dist Thresh .1

Interp. frames 2

 

Light Cache-

Subdivs 1000

Sample Size .02

Scale (Screen)

Number of passes 8

Depth 100

Multiple Views (Unchecked)

Store direct light (Checked)

Show calc phase (Checked)

Adaptive tracing (Unchecked)

Use directions only (Unchecked)

Min paths per sample 16