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Corona interior - Wip

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Ondra:
HDRI size should not affect render times

Ludvik Koutny:
There should not be any significant difference between PT+PT and PT+HD when it comes to light passing through the light shader, and in case there is, i would rather use PT+HD, and increase translucency of light shade, than use PT+PT, because PT+HD will give you a lot more reasonable rendertime.

I believe many of the problems in your scene might be caused by improper material setup. Material converter by DeadClown is really great for MR's Arch&Design materials, but is not remotely reliable for Vray materials.

My suggestion would be to:

1: resave scene as a new file
2: delete all materials
3: apply diffuse gray (RGB 160 to 170) material on everything
4: set GI to PT+HD
5: hide glass in windows and do the lighting first (enviro HDRI + interior lamps)
6: unhide glass planes in windows, create glass material for them, and make sure they don't impact performance (twosided glass material)
7: start with materials of objects close to light sources, such as lamp shades, and observe how they affect amount of noise in scene, avoid glossy refraction if possible, and use translucency instead. Avoid using opacity value at all cost if possible.
8: add rest of materials one by one. Make sure you have control over them, so do them manually (no conversion)
9: for optimal performance, try to avoid fakes, especially disabling shadow casting.

It might imply that if you disable shadow casting of a light shade for example, it will make rendering faster, but in Corona, it can actually impact performance in a negative way.

maru:

--- Quote from: Keymaster on 2012-11-01, 21:33:44 ---HDRI size should not affect render times

--- End quote ---
ORLY? Here's a quick comparison.

30s_hi.jpg:
render time 30s
PT only, 16 samples
HDRI env map size: 6000x2900px

30s_lo.jpg:
same render time, same settings
HDRI env map size: 300x145px

It's only a 30s rendering, but noise difference is significant. Using a downsampled or blurred hdri as env map always helps reduce noise, especially on glossy surfaces with bump maps, because it becomes more uniform in terms of colours and intensity.

Ondra:
This is an extreme case, you've modified the scene description a lot by blurring the map. And even then I would say that the difference isn't huge.

Chakib:
@andreupuig : I did try corona sky, but i've wanted an envirenement image outside, so i did use hdri, but since i can't exclude the bended plane with and image emission material, i did use the hdri source.

@maru : I did use the translusuant simple corona material with value 0.5

i don't think the hdri size will affect the render, but in vray i think it does.

@Rawalanche : thanks for tips, but i did verify every object materials after conversion carefully, i didn't foudn anything strange the materials were clear to me. maybe my  render parameters are not well chosen, i'll apply the hd cache again and see of the lamp will be good or not. I did use the twisted thin glass since i've read here that it's good for windows and for sun light throught glass. One thing that's annoying me is the bump value, sometimes is act good sometimes it doesn't appear even in the highest value, or it's just me maybe...

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