[gotoxy av-media]

hi maxwellians,

i know this topic has been discussed several times...but

1. maxwell-render has finished (banding is visible!)
2. added a little diffraction/scatter to the image.
3. result on the monitor is a banded image with nice scatter

to remove the banding:

5. saved as HDR and opened in Photoshop...ANTI-ALIASING IS GONE!
6. downsampled image from 32bit to 8bit to remove the banding
7. result: banding is removed but an ugly AA appears

so please, what did i do wrong? tips&tricks???

why can`t maxwell-render save a correct 8bit-image without banding?

help please!
munch

[gotoxy av-media]

hmm, many views but no reply

nobody out there having the same problem?

munch

[polynurb]

hi munch,

i don't use scattering a lot, but i know that issue with bright areas getting aliasing artifacts under certain conditions when render is saved as hdr.
and i think it is what we see on the legs of the chair.
(try with scattering turned off.. if it is still there)

similar thread:
http://www.maxwellrender.com/forum/view ... =hdr+gamma

tbh.. i don't think there is a solution for this yet.

[Cadhorn]

i'm not seeing the banding you're referring to in the image on the left.
i *can* see the problems with the image on the right, the little weird artifacts on the chair leg.

my only thought, since the whole scene is lit by a single HDR, is that there may be some banding in the HDR image, thus the reflection on the floor is showing some of that banding.
i would start to troubleshoot the banding by taking a really good look at the HDR that's lighting the scene. or maybe try a render with HDR reflection turned off (use sun or skydome for reflections), just as a test.

your step 6 puzzles me "6. downsampled image from 32bit to 8bit to remove the banding" i'm trying to think of any reason why downsampling would *reduce* banding instead of increasing it... doesn't make sense to me. going from 32 bit down to 8 bit (or 16 or 24) reduces the total number of available colors in the image, which should make any visible banding more apparent.

[gotoxy av-media]

thank you polynurb and cadhorn for the replies,

i did some more tests and what i found out:

-even when scatter/diffraction is turned off, saving as hdr leads to this anti-aliasing bug

-saving as 8bit png,tif, etc. anti-aliasing is correct!


---> is maxwell-render not able to convert to hdr-format correctly?!? is it a bug?!?


so what to do?
i have to save it in 32-bit to get rid of the banding in photoshop,
but the only supported format is .hdr (.exr doesn`t work (yet!))

is there another method of removing the banding than importing 32bit to photoshop and save as 8bit?

thx
munch


@cadhorn: do you own a hdr-monitor ? if not take a closer look!

http://www.maxwellrender.com/forum/view ... 787#275787

[Cadhorn]

i do see the banding in the image on the left, i even referred to it later in my previous reply... i dunno... i confused myself in a single paragraph!

i'm still curious to know if that banding may be caused by the HDR that you're using to light the scene. do other HDR's result in the same banding?

[gotoxy av-media]

banding does occur quite often in gradients and can be fixed easily (see link in my last reply)

so i don`t care about banding and my used hdrmap...

but i am very unhappy with this anti-alias-problem (legs of the chair)
which only appears when saving the rendering as hdr.

AND THIS IS THE POINT:

i have to save the rendering as hdr to get rid of the banding...
but maxwell cannot save as hdr correctly!!!
and no other 32bit format (.exr) is supported

[gotoxy av-media]

hello,

just rendered my old scene with v2:

-when saving as 8-bit the image looks nice! no AA-steps visible and no banding in the background!
-32bit output HDR looks much better than v1.7, but still some AA-steps are visible...

munch

[tom]

-32bit output HDR looks much better than v1.7, but still some AA-steps are visible...

You will need a true HDR display It's just not possible to avoid it because the resolution is very coarse to represent that range in illumination. Far beyond AA can compensate.