Opacity

[aflack]

Can anyone tell me why when I apply a tree material to a flat plane, and apply an opacity map to the opacity channel, when I then render using Mental Ray there is a brighter area around the tree where there should be nothing.

 

See attached image.

 

Thanks

[STRAT]

switch off all specular/shiney properties of the material

[jysngltndz]

yup glossiness and speculars, try removing it...what shadow type are you using? as i know raytraced shadow works well with opacity. just try it with mr.

[aflack]

I guess I must be doing something wrong, I have taken all the specular and gloo off the material. Also I am using Ray trace shadows.

 

Have a look at my material settings below.

 

Thanks for yoru patience.

[William Alexander]

aflack,

 

Two things to consider

 

1. is your mask absolute 000 & 255 (black white), adjust that map in the Materials>output>colormap to see if that eliminates the problem or check in PS

 

2. Environment effects such as fog always brighten the 'opaque' or masked part of an object, turn it off if using

 

 

rgrds

WDA

 

e-p.s. thats some funny looking 'frosted glass' LOL

[jucaro]

Check enable PROCESS BACKGROUND AND ENVIRONMENT MAPS in your exposure control found in the environment tab of your environment and effects dialogue.

[kicks]

[aflack]

Thanks for all your help, I ended up placing the tress in Photoshop but in my new image I want the trees to reflect in the glass.

 

I tried what Jucaro suggested and it does get rid of the glow round the trees but it blows out the background image as well.

 

There must be a way around this if you want to use an background image thats also my environment map?

 

Please see the attached images for what I mean!

[noi-pi]

Thats exactly what happen to my opacity maps if i didnt check process env maps. It works but what happen was just like that! Overblown env background. From then on I shy away with Exposure Control. Besides I don't want to add another settings aside from Render Dialog box.

[aflack]

So is there no way you can get around this then?

[kicks]

[aflack]

I tried that Kicks and unless I am missing something so the same blown out background occurs.

 

I placed a large sphere around the whole image, I inverted the normals so it faced inwards. I applied a standard material to the sphere and made the material 100% transparent, in my viewport the background is now covered with 10 of tiny dots simulating a transparent material I render the same image but I still get the blown out background as before.

 

I have tried turning up transparency and turning off visible to camera. But the same thing keeps happening. I assume it is because of the environment map. There must be other people that have come across this problem and found a way around it?

 

Please help!