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gauravindian
06-08-2008, 11:10 PM
I was trying to texture map a tree image on a poly plane.
Here is the original image

http://img71.imageshack.us/img71/166/treee11gl8.th.jpg (http://img71.imageshack.us/my.php?image=treee11gl8.jpg)

Here is the alpha image(i saved it as .tif)

http://img71.imageshack.us/img71/7992/treee2222qm4.th.jpg (http://img71.imageshack.us/my.php?image=treee2222qm4.jpg)


Shaders

http://img71.imageshack.us/img71/974/treeee33333yf8.th.jpg (http://img71.imageshack.us/my.php?image=treeee33333yf8.jpg)

I dropped the shader on a poly plane.And this is what i am getting at render time

http://img71.imageshack.us/img71/268/2222211ry1.th.jpg (http://img71.imageshack.us/my.php?image=2222211ry1.jpg)


I want to remove that black part.So that only the white part of alpha is visible.How can i do that?

I tried to import this in front plane.And i got exactly what i wanted

http://img71.imageshack.us/img71/3707/treee44444hi3.th.jpg (http://img71.imageshack.us/my.php?image=treee44444hi3.jpg)

Only tree was visible.So how can i get the same result at the render time.I hope i have explained my problem. :rolleyes:
srisha
06-09-2008, 04:15 AM
Hi Gaurav,

The problem is with Blinn material, which is giving specular highlights in the transparent part.

We can fix this by either changing the material to Lambert or turning off "emit specular" of the lights linking to the object. Hope this helps.
gauravindian
06-09-2008, 01:53 PM
Hi Gaurav,

The problem is with Blinn material, which is giving specular highlights in the transparent part.

We can fix this by either changing the material to Lambert or turning off "emit specular" of the lights linking to the object. Hope this helps.
Thanks man.I changed the material to lambert and it worked.
NoshDir85
06-09-2008, 09:58 PM
I know you wouldnt use this on a tree material, but for future reference if you need transparency with a material that utilizes specularity, make a seperate spec layer and make the "transparent" parts black, and the rest of the image to taste according to how specular it is...this will essentially cut out specularity for the transparent parts.
gauravindian
06-10-2008, 08:26 PM
I know you wouldnt use this on a tree material, but for future reference if you need transparency with a material that utilizes specularity, make a seperate spec layer and make the "transparent" parts black, and the rest of the image to taste according to how specular it is...this will essentially cut out specularity for the transparent parts.
Sorry but i didnt get the separate spec layer part.Can you explain it with an example.Thanks.
leigh
06-10-2008, 09:04 PM
Sorry but i didnt get the separate spec layer part.Can you explain it with an example.Thanks.

I'm assuming he means you should create a map for it, which would indeed be a simple solution. Simply create a specular map that is black in the areas that you want transparent. That way, you'd have some specular highlights on the solid areas, with no specular in the clipped (transparent) areas. Although, with this kind of technique, I'd guess you probably don't need specular, since it is just a flat plane anyway.
gauravindian
06-11-2008, 07:34 PM
I'm assuming he means you should create a map for it, which would indeed be a simple solution. Simply create a specular map that is black in the areas that you want transparent. That way, you'd have some specular highlights on the solid areas, with no specular in the clipped (transparent) areas. Although, with this kind of technique, I'd guess you probably don't need specular, since it is just a flat plane anyway.
Thanks.I will give it a try.
jpiette
06-15-2008, 06:06 AM
Everyone who has posted their answers are correct, it's a specular problem. Most people don't realize at first that in order to make a true cutout in CG, you have to place the alpha in the opacity AND the specular layers, otherwise the result is what you saw in your renders. I used to make this mistake all the time when I first started out. It's a bit harder to fix in Maya than in Max, but basically stamping it out in your specularity settings within the connection editor should do the trick.
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06-15-2008, 06:06 AM
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