Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: mtanasiewicz on 2015-08-10, 12:39:31

Title: Problem with small leaves on bushes
Post by: mtanasiewicz on 2015-08-10, 12:39:31
Hi all,

I have a problem, when I render bushes with small leaves, from the distance they appear desaturated. From close ups everything is ok, the bush is green. I tried to lower bitmap filtering in Corona bitmap opacity. I remember that I did have the same problem in Vray with some bushes, but I've never figured it out. Maybe some of You have a clue?

Thank's in advance
Title: Re: Problem with small leaves on bushes
Post by: PROH on 2015-08-10, 12:56:14
Hi. Have you tried to disable bitmap filtering completely for the opacity channel?
Title: Re: Problem with small leaves on bushes
Post by: mtanasiewicz on 2015-08-10, 12:57:42
Yep, I lowered filtering to 0,0. Nothing has changed
Title: Re: Problem with small leaves on bushes
Post by: maru on 2015-08-10, 13:19:07
You can use CoronaBitmap for the textures (if you are not using it already...) and set filtering to 0. I am not sure if you followed PROH's advice: have you set "texmap filtering" in F10 > performance > devel/experimental to "none"? Another solution is to paint the white area in the diffuse bitmap to green.
Title: Re: Problem with small leaves on bushes
Post by: PROH on 2015-08-10, 13:25:50
Hi. I don't think we are talking about the same thing. I think you are talking about "blur" amount, but I'm talking about setting filtering to "none" instead of "Pyramidal" or "Summed". Se the attached picture.

PS - my advice is regarding Max's "standard" bitmap loader.
Title: Re: Problem with small leaves on bushes
Post by: mtanasiewicz on 2015-08-10, 13:30:10
But I'm using corona bitmap as opacity map. There isn't any filtering option like in standard bitmap.  I have also tried disabling filtering for opacity maps when I rendered those plants with vray. I also have tried to paint the bitmap to green outside the leaves. Nothing really helped... I'm wondering if it has something to do with the leaf size. The problem only occurs when I use bushes with really small leaves like 0,5-1cm diameter.
Title: Re: Problem with small leaves on bushes
Post by: mtanasiewicz on 2015-08-10, 13:33:29
Allright guys problem solved. The diffuse bitmap was actually a png image with alpha channel. I opened it in PS, flattened and painted the rest of the map to green and now everything is okay.
Title: Re: Problem with small leaves on bushes
Post by: romullus on 2015-08-10, 13:57:06
@PROH filtering of opacity maps is disabled globally by default, so usually it's not necessary to turn it off in maps itself.
Title: Re: Problem with small leaves on bushes
Post by: PROH on 2015-08-10, 15:50:20
aaahhhh... Didn't know that. Thanks for the info :)
Title: Re: Problem with small leaves on bushes
Post by: maru on 2015-08-10, 17:11:08
Confirmed.
Title: Re: Problem with small leaves on bushes
Post by: maru on 2015-08-10, 17:15:44
Ah, ok, I get it, it woks like this in scanline too. When there is alpha in diffuse, the "background" diffuse color gets displayed. Alpha gets slightly blurred in diffuse channel and it overlaps even if opacity map is perfect. So another fix is to set diffuse color to green.