[simonhnelson]

I am rendering a 20 storey building and am finding a problem I have not seen before. As the building gets higher, the whole render gets darker and it simply looks wrong. i have played for a few days with different HDRI skies and different settings but am totally stuck and have very little time to get this right. HELP! please.

[ababak]

Hi,

Could you show your scene setup and the render you get?

[dk2079]

Have you disabled vignetting?

[simonhnelson]

Hi, and thanks for your quick replies.

I wanted to post a render to show the effect but don't seem to have the option of attaching a file.

I forgot to mention that i am using the Rhino plug-in.

Thanks for the tip on vignetting. I haven't come across that setting so will look it up

[simonhnelson]

I don't know what to say!!

The problem was vignetting. Thanks so much. You have saved me!

[ababak]

I wanted to post a render to show the effect but don't seem to have the option of attaching a file.

You need to upload your image somewhere else first. I prefer Dropbox. My workflow is making a screenshot, putting it to dropbox folder, right-click > Copy Public Link. Then you press the "Img" button in the post editor and past the image link.

Glad you solved your original problem.

[dk2079]

The problem was vignetting.

That's good.
Like in a real camera in Maxwell vignetting gets stronger as the lenses angle gets wider.
If you also use lense shift you can end up with an image bright on the bottom and dark on top as you "hide" the second half of the frame.
It has been discussed before why vignetting is turned on by default and I think it is more a compatibility thing; it has always been like that in Maxwell and changing defaults is usually causing trouble to established workflows.
But since it's a post effect, you can turn it off any time.

[simonhnelson]

Not only am I using a 15mm wide angle lens but I am also using the lens shift (-40y) as well so I was getting double the problem. I think a mix of the geometry of the building, plus one elevation that is very much a single colour has accentuated the effect.

Agree that it is a bit strange to have vignette on as default, but I guess that is part of the philosophy pf the software, to make it as much like using a real camera as possible.

Thanks once again fro all the help.

[seghier]

why you don't simply post screenshots ?