Cut poly by alpha?

[achoury]

Hi!
Is it possible to automaticly cut a poly plane by using an image with alpha? the reason why i want this is becuse i want to use imageplanes with alphas to work with accurate occlusion aswell.. any ideas??

Hi
You can achieve what you want by using mib_fg_occlusion and mib_transparency.
So plug the node mib_fg_occlusion to the Shading Group for the first material.
and mib_transparency node to the Shading Group for the second material.
Then assign the texture you want to cut to the Transp slot of mib_transparency node
Activate Final Gather and render that's all

http://www.postmyimage.com/images/images7No51567.jpg

hope this what you want

/Rachid

[illbrat]

incredible! Its exactly what I wanted!
Thank you alot!

[Kinematics]

Sorry Achoury, I still can't get the connections exactly. Could you be more specific? I used two surface shaders and added the fg_ao and transparency to the other. I'm getting black around the alpha

Okay I got it to work by creating two surface shaders and I had two mib_fg_occlusion's attached to each. I connected the mib_transparency to the surfaceshader group node and then broke the connections with the original surfaceshader which I now connect to mib_transparency via outColor->input and I mapped the alpha image to transparency.

Somehow I think its not correct though it works. What did you do Achoury?

[achoury]

Sorry Achoury, I still can't get the connections exactly. Could you be more specific? I used two surface shaders and added the fg_ao and transparency to the other. I'm getting black around the alpha

Okay I got it to work by creating two surface shaders and I had two mib_fg_occlusion's attached to each. I connected the mib_transparency to the surfaceshader group node and then broke the connections with the original surfaceshader which I now connect to mib_transparency via outColor->input and I mapped the alpha image to transparency.

Somehow I think its not correct though it works. What did you do Achoury?

Hi
You don't need to have two mib_fg_occlusion, use just one!
So create one lamber_A and assign it to all the objects except one that you want to use with mib_transparency.
Create another lambert_B and assign it the the object you want to cut with the texture.
Create one node mib_fg_occlusion and plug it to the Sahding Group->material Shader of the first lambert_A.
Create one node mib_transparency and plug it to the Sahding Group->material Shader of the first lambert_B.
Connect the output of your texture to the Transp parameter of the node mib_transparency.
Your texture must be black and white, Filter Type Off and Alpha Is Luminance On.
The Input of the node mib_transparency must be white.
take a look at the attached scene.
/rachid

[Giap]

It works as a charm :D

Thank you, Achoury.

[achoury]

It works as a charm :D

Thank you, Achoury.

Thank you, but why do you leave the the Input of the node mib_transparency black?
Put the value to white. or something like 0.8

http://www.postmyimage.com/images/images32O49009.jpg

/rachid

[Giap]

It's just for fun. I saw it looks more interesting when there is contrast in the final render :D but I did understand your technique though.

[achoury]

It's just for fun. I saw it looks more interesting when there is contrast in the final render :D but I did understand your technique though.

well it's not my technique, but I can't remember where I read an article about that! maybe Lamrug or here in Cgtalk.
/rachid