DOF in post with glass, refraction and reflection problems

[aio]

Hello forum,

I'm trying to achieve this kind of effect but in post.


I tried with the p_z shader on separate channels with arch material X, but i have trouble with the reflections, i have only one level of depth and with the refraction, same values of IOR give me different results than with the arch material.

Is it realistic to hope to achieve this kind of effect?

thank you

[Letterbox]

Yes you could do that in post.

You'll have to be aware of many things, as I'm sure that the image is not the final scene. That said, you''ll need know to export mattes, reflection passes (possibly per object), and depth pass's. You also need to know how to setup framebuffers for the Mia_Arch shader (I think there was a version of the mia shader that let you output everything in raw uncorrected form). In AE you have to know how recombine in the right order, pre-comp, know how DOF works in AE, or look for a Rack focus style of plugin and how that connects to the depth pass.

As for depth passes in SI, look the great tutorial site http://caffeineabuse.blogspot.com/.

So it can be done, but think carefully what passes you'll need, where and what the dof effects for your specific scene. As every scene and camera move will change what you need.

[Falam]

CG is making it from scratch, then tearing it apart in the end layer by layer, unless the last step is skipped.

[Rork]

Or try to buy into a more modern renderer....

[aio]

Or try to buy into a more modern renderer....

Please name one !
I'll try to post some screen grabs on the next days

[Rork]

well... i could say Arnold, but that's just plain mean to most of us here ;)

Maybe more modern isn't the right word, but have a Google on renderers and plugins for Softimage.
You'll be amazed how many renderers are out there now, free or commercial.

rob

[origin]

all renderers out there have dead slow DOF...

[Falam]

Isn't wise to do DOF in post ?
Here is a suggestion, if you do a render and someone tells you, oh that render would look killer in <render engine name> then you could consider.

Why I personally don't use another render engine besides MR is I have to substitute the factory MR nodes with the other render engines nodes, that isn't hard, but learning the new nodes takes time and I still am rusty in ICE, I rather get more acquainted with ICE then another render engine.

[ActionArt]

3Delight does quite well at DOF and directly converts most nodes so there is little to learn. If you need DOF in 3D and perhaps motion blur and or displacement mapping it might be a good choice.

[Kzin]

there does not exist one renderer which can solve such scenes with good rendertimes when it comes to raytracing (nor 3delight or arnold or mr or vray or octane). because you have to shoot rays to refine the dof you will always end up with extrem high raycounts for smooth solutions which means you have to render a long time. thats the reason why most time its done in post, better quality with way better rendertime (and dont forget the control you have in post).

this scene is worst case and if you have to render images only then i would say render the dof. for animation, you can use shaders from the ba shader pack from holger schoenberger to get correct mattes for postblur. this needs some more shadersetup, but its possible to get them so you can do some ok'ish post blur. ;)

[aio]

Well kzin i tried the BA shader but i couldn't figure how there are useful in this case, there's a setting for reflection ok but the transparency setting gives a weird looking look like an occlusion pass how 's that related to refraction?

My scene wil only have one or two bottle (with thickness and and a different ior inside) and basic reflections but i'm relatively new to applying a zpass separately on refractions and reflections.

[aio]

So here's the deal : the z_pass shader give me different refractions than the arch material. And i don't know why.
Simple sphere, nothing fancy. So far i'm stalled. If someone has a better idea how to do that, i'm listening.

[Kzin]

is this also different then you deactivate the reflection of the arch mat and render only refraction?

[aio]

yep i compared with the refraction of a lambert also. Same thing. I mailed the author maybe i'm doing something wrong.

[Kzin]

yep i compared with the refraction of a lambert also. Same thing. I mailed the author maybe i'm doing something wrong.

have you tryed to create a custom pass with gradient falloff of the scene and transp/refract on?

[aio]

could you be more specific? function to use? like a fog?