blurry reflections tip

[STRAT]

hi guys.

 

this is a C4D tip, but i suppose it can apply cross-app

 

rendering reflections in cinema is fairly fast, but start playing with the blur spinner and the render times hit the roof!!!

 

This is a tip i thought of which works most effectively for blurring reflections at next to normal rendering speeds -

 

create your material as per usual, and in the REFLECTION channel put in a noise map or noise shader scaled down untill it's a quite fine noise. then this noise map can be smoothed out using the samples spinners in either SAT or MIP mode (equiv. of max's super sampling). smooth it out about 20%.

 

then try rendering. the reflections should then be smoothed out.

 

the noise size and smoothing amount will have to be played with to accommodate your scene, but this doesn't slow down rendering anything like proper blurring does.

 

also make sure MIP falloff is checked to give added realness to the sampling. For extra realism, render out your scene to a PSD photoshop file with the reflections channel on a separate pass and some post photoshop work will give extra control.

[matt_vinoir]

nice! ( i said that in the style of the fast show jazz man btw)

[jackb602]

Strat,

 

I've played with this tip for a while, and I've never been able to make it work. Would you mind sharing a shader using your settings? Also, does this technique work for blurred transparency too? I'm working on a walkthrough animation that uses channel glass for interior partitions. I want to show the slightly blurred transparency of this glass, but I'm trying to keep render times down. Any advice? Thanks,

 

Jack

[Ernest Burden III]

Another gem! Does this have anything to do with slaying dragons? (it's national 'let's all go out and slay dragons' day in England).

 

That is a technique I have used in Lightscape--use a REALLY small procedural bump. And yes, that is how I make frosted glass in LS, I bet it works in C4D too.

[STRAT]

i'll post something up next week. if i forget please remind me

[jackb602]

i'll post something up next week. if i forget please remind me

 

Hey Strat,

 

Would you mind posting one of your blurred reflection/transparency shaders when you have a chance? I'm just finishing an animation that uses real blurred transparency, and the render times have been keeping me up at night. Thanks,

Jack

[STRAT]

Jack - this is about how close a noise map will blur. it renders much faster than blur, but does have it's obvious limitations (ie, i cant vouch for it's flickering during anims) also, i know not how it's react as a glass texture. i pressume with some tweeking not too bad.

 

but it would be a much faster work around for still work if you also render it to a psd file and blur out the ref layer in ps -

 

[jackb602]

Strat,

 

Thanks for the examples, they look good. Would you mind sharing the actual settings you used, or even a C4D file? I've tried all kinds of noise and haven't gotten results like yours.

 

Jack

[STRAT]

http://www.nikclark.com/strat/blur.zip

 

 

you can probably play around with some of the AA settings to speed things up

[jackb602]

Thanks for posting the file Strat, but I opened it and it doesn't contain any materials.

 

Jack

[STRAT]

it's an 8.5 file. i dont know wether earlier versions contain the same noise filters.