Remove lining around Alpha Channel

[NOOXY]

how do u remove the matting around the alpha after u have placed it into your scene..i get a white background around it..

 

using c4d...can someone advice me please..

 

cheers

[leed]

clone the colour beyond the alpha map.

 

Lee

[NOOXY]

can you elaborate more on what to do..i'm still a bit lost:confused: ..

[STRAT]

this is also usually a case of better bitmap preparation. make sure your tree bit map has a green backround (or as leed suggests, a neutral backround, ie, green/blue). this helps to eliminate an 'edge'. your alpha map version then has a nice green edge to play up to.

 

also, give the alpha map channel in the material editor a spot of SAT blurring. this will take the 'edge' off the edge.

 

you might also want to 'stroke' your alpha map in photoshop with a mid tone grey colour. again, this helps to eliminate the hard edge.

[Jorge Arango]

Try the different combinations of settings in the alpha channnel: invert, soft, etc. I don't know exactly what each setting does but I have solved that kind of problem trying the different combinations. (There are 16 combinations).

 

Hope this helps,

 

 

Jorge Arango

[leed]

I am assuming the trees are pictures on planes, you have an alpha map and a colour image map. in photoshop clone extra green tree leaves so that the colour map extends passed the alpha. That way you should not get any white edges.

 

The other way if you do not want to re-render is to select your alpha channel in photoshop and contract the selection by 1-2 pixels, this will eat in to the image a bit though.

 

hope that is clear.

 

Lee

[NOOXY]

thanks for the info.i'm actually using textures from the 3d total collection so i'm assuming they would be great alphas already and just some setting in c4d which corrects this situation..thanks again to all

 

nooxy

[martinp]

The other thing you should check out is the section in the C4D manual about the different kinds of alphas that exist. The section on rendering output goes into some detail about pre-multiplied or straight alphas etc etc.

 

If I was seeing this in any other compositing tool, I'd say check your alpha image state in the first place. White or black fringes are the two most common results.

 

Good luck,

 

Martin

[LordRaven]

You can do a separate rendering with a pure white material assigned on everything you need in the alpha chennel, while everything else being pure black. No gi, no lights... Use this mask instead of the alpha chanel output. This should work with every rendering software.

 

I hope it helps

[Frosty]

You've got a few possible methods already posted here and all will work. I'll offer one more.

 

Open the colour map in PS.

Duplicate its colour layer.

Select the lower of the two layers and use Guassian blur(2-5pixels depending on map size).

Flatten layers and save.

 

This could be done with a batch action on an entire directory in a few minutes. You may also choose to add a uniform scale operation of about 102% prior to the blur.