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clemse

Transparent without backside ?

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Hey everyone,
I'm currently working on a scene where objects in a cloner move along a spline towards the camera.
I'm controlling the transparency of the objects that are getting closer to the camera via plain effector so that other objects behind them dont get covered.
Unfortunately the transparency in cinema unveils the backside of the "close to camera" objects as well. This complicates the legibility of the szene.
I was wondering if there is a way to make objects transparent without showing their backside but still seeing objects behind them. Kinda like it would look in photoshop when you have 2 layers with objects covering each other
and lower the opacity of the upper one. Im very thankful for any hints, thx in advance

example.png
Edited by clemse

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Think this should work, apply a "Compositing" tag to the object, then go to "Exclusion" tab and put that same object into the "Exclude" box and make sure the "transparency" (arrow angled going thru line) icon is active.

 

Fingers crossed that this is what you were looking for.

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Unfortunately the exclude thing didnt work as I had hoped. The backside seems to have disappeared but i get mask like cut outs in the scene all of a sudden. Do you have an idea what the problem is ?

@ J Montreuil , Ive never heard of the term self-culling before . I googled it and got a lot of results related to the sketch and toon shader . Are you sure this is an option that can be used apart from s&t ?

Edited by clemse

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Unfortunately the exclude thing didnt work as I had hoped. The backside seems to have disappeared but i get mask like cut outs in the scene all of a sudden. Do you have an idea what the problem is ?

 

@ J Montreuil , Ive never heard of the term self-culling before . I googled it and got a lot of results related to the sketch and toon shader . Are you sure this is an option that can be used apart from s&t ?

 

Sorry I meant Backface Culling. Its in the Display tag. That might be it?

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Sorry I meant Backface Culling. Its in the Display tag. That might be it?

 

This only a display option but you can try putting the normal direction shader into the alpha channel to render one side of a polygon but not the other.

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This only a display option but you can try putting the normal direction shader into the alpha channel to render one side of a polygon but not the other.

 

This works in some ways but you'll still see thru the object itself if the object goes somewhat into itself like the little cells do since their normals are still facing the camera. I'm thinking the OP's goal is to have the whole thing be transparent evenly so you can see the objects behind it.

 

Left: normal Center: Alpha with normal direction Right: exclude object transparency to itself

 

xZzd73e.png

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Yet another practical reason for deep compositing. Using depth info in something that supports deep compositing would work. It would be faded within the composite instead of within the 3d.

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There is no need whatsoever for any deep compositing here. You just need to craft a custom material using the Normal Direction shader in combination with the Proximal shader with the camera acting as the reference point for the distance...

 

Mylenium

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I like the idea of deep composition here as you would have flexibility to change or even animate the transparency in the compositing app. I still haven't figured out a workflow to use it from Cinema4D R16 yet.

 

How do you get the XYZ of the rendered pixel into the OpenEXR file?

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Hey Davor, the version on the right is exactly what I wanted . Unfortunately I'm having difficulties with the upload manager here.
https://dl.dropboxusercontent.com/u/20138515/rbc.c4d

The exclusion of the transparency doesn't seem to be working with my setup though. I used the plain effector in combination with a colorshader in the alpha channel and honestly don't remember which part of the plain effector controls the colorshader.
What am I doing wrong ?

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Seems to be working for me with this file, I'm not getting any strange clipping, I've put a grey background just to make sure there wasn't anything funny.

 

1aaGspM.png

 

4OHKpll.png

 

Other than adding in that Composite tag I didn't do anything different to the file.

 

Let me know if I missed something.

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