[Guns_888]

Hi All,

Encountered a problem I haven't come across before. I am experiencing a high level of noise in relation to the amount of time that the images have been rendering for.

I have left the render going for 44 hours over the weekend on an 8-core/8gb ram rendering server at our office. Unfortunately I closed the mxcl screen before noting the SL.

Please take a look at the two images below, one a resized version and the other a 100% crop of a central part of the image.
The original render is 4000 x 2000 pixels.

The scene has 4 levels of furniture, is using the skydome as an environmental light-source at 9000 intensity (!) and 'use sun' selected. The colour of the light is R: 200 G: 200 B: 200.
Lights have been made into one object per level of the building and consist of 5mm thick rectangles. Emitter colour is R: 255 G: 255 B: 255 (thinking that this might be the problem?).
Material palette - AGS Glass, Shiny Plastic, Glossy Plastic, Arroway Timber Material, Chrome, and a Custom Emitter (10000000 watts!).

Should also add that the furniture is cloned by floor rather than instanced - something else I think I should probably change.

Any help appreciated. I'd have thought that 44 hours runtime on that setup would've produced fairly clean images. I have another view of the same internal space that has the same problems after an equal amount of rendering time.

Cheers/


Full image



100% crop

[JorisMX]

You can reopen the mxi mxcl saved and it will display the Sample Level in the upper left hand corner.

About your problems:

I hardly do archviz but this noise problem is usually related to the same errors:

1. Wall material too white. Don't use 255/255/355 for white
2. Having the wrong glas material assigned to all the windows and building openings and sometimes I think even AGS can be used wrongly.
If you dont see the glass just leave the windows open so the light won't have to pass the material.
3. Very high Multilight ram usage e.g. change your ML and agjust to your scene for non ML rendering
4. Using the Sun instead of Emitter planes will often result in noisy renderings when lighting a building from the outside only.


I would search the forum for noise windows glass ags and / or the usual terms going with these issues. It has been discussed pretty often.

[Guns_888]

You can reopen the mxi mxcl saved and it will display the Sample Level in the upper left hand corner.

About your problems:

I hardly do archviz but this noise problem is usually related to the same errors:

1. Wall material too white. Don't use 255/255/355 for white
2. Having the wrong glas material assigned to all the windows and building openings and sometimes I think even AGS can be used wrongly.
If you dont see the glass just leave the windows open so the light won't have to pass the material.
3. Very high Multilight ram usage e.g. change your ML and agjust to your scene for non ML rendering
4. Using the Sun instead of Emitter planes will often result in noisy renderings when lighting a building from the outside only.


I would search the forum for noise windows glass ags and / or the usual terms going with these issues. It has been discussed pretty often.

Hi Joris - thanks for your reply. If I can respond to one point at a time:

1 - I have changed the reflectance 90 value to 237 237 237 instead of the 255 255 255 (reflectance 0 was already set at 237....)

2 - Good tip for the glass, will try taking glass out for external walls

3 - Not using ML

4 - Will have a go at inserting emitter planes - what, typically, are the values used for such emitters that aim to replicate the sun?

Many thanks/

[Mihai]

You could also optimize your emitters so they are a single poly plane, no need for them to have thickness. Also the white material looks a bit too white and in the areas where there is only this material you see there is more noise, the light just keeps bouncing around because it's losing very little energy. You could use around 215-220 for the white material. Emitters and the refl90° color can be left at 255. It's the refl0° color you should watch not to set it too bright, for reference a white piece of paper would be around 220 brightness.

Do you want direct sunlight in this scene or just diffused lighting? In that case no need to use the sun from the Physical Sky.

[Guns_888]

Thanks Mihai.

I would like direct sunlight (it'd be ideal to see the light from the sun come directly through the top of the atrium and cast light and shadows on the floorplates below) but I can't seem to artificially point the sun just off directly vertical!

Would 'use sun' have a huge effect on the noise?

[-Adrian]

an environmental light-source at 9000 intensity (!)

What you say, 9000!?

i know, i got nothing useful to contribute to this thread :/

[Bubbaloo]

Always start with realistic emitter / skylight settings and adjust your camera params to suit the scene lighting, not the other way around. I don't know if that has anything to do with extra noise, but it's where I would start. To tell the truth, a scene of this scale and complexity will take VERY long to clear.

What is you roughness value on the white material? Don't set it too low, it will create more light bounces.

Are you using instances in this scene? If your computer can handle it, turn them off. It will give you a better benchmark.

BTW, It's a cool scene!

[Guns_888]

Cheers Bubbaloo.

I hadn't considered setting the scene up realistically and adjusting the camera settings to suit - that's a good idea. I'd always thought 'I need more light, so I'll give myself more light...!'

The roughness value on the white material is 30 - does this sound high enough?

RE: Instances - I tried to instance each level of furniture but then, when rendering, the instanced objects do not appear so I have had to clone the levels.

Scene will have ghosted people / activity inserted in post - will upload a final version once complete, if only I can get it cleaner!

[Bubbaloo]

The roughness value on the white material is 30 - does this sound high enough?

It depends... Is it a two layer material? What is the surface material supposed to be? Painted?

Anyway, 30 sounds too low. Try a test at 90 - 95 and see if it makes a difference.

[Guns_888]

It's the standard white glossy plastic that is included with the maxwell library.

I'll try bumping it up to 90 as you suggested.