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panphoto
11-21-2012, 05:53 AM
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Hi, Does anyone have an idea why I can't properly render fibres thru glass? The attached renders show the problem. From left to right the first image is using radiosity, the next global illumination and the third, radiosity without the glasses. I'd be grateful for any suggestions, Thanks. David

lardbros
11-21-2012, 06:03 AM
The standard FFX won't render in reflections, or through transparent objects unfortunately... just the limitations of a post process effect.

BUT, try changing the mode, within the FFX panel, to VOLUME. Depending on the version of LW you have, it should look okay in 11.0.3.

I know for 11.5 there are some fixes in there so that FFX will automatically render Volume fibres when a reflection/refraction is occuring.


If this doesn't work, not sure what to try next!

jwiede
11-21-2012, 11:20 AM
The standard FFX won't render in reflections, or through transparent objects unfortunately... just the limitations of a post process effect.
Look at the examples again: The first example has FFX hair rendered through the glasses' lens no problem. If FFX renders fine behind transp when raytracing is used (OP said "radiosity"/"GI"/"radiosity" but guessing meant "raytracing" not radiosity), then I'm not sure ye olde "post process limitation" argument really applies here, as the post process limitation should impact both raytracing and GI similarly.

RebelHill
11-21-2012, 11:42 AM
I know for 11.5 there are some fixes in there so that FFX will automatically render Volume fibres when a reflection/refraction is occuring.

Shouldnt be 11.5... that feature is in the current version (1101+ if I remember correctly).

panphoto
11-21-2012, 02:58 PM
Thanks Guys,
Yes, FFX does render through glass but becomes very sketchy as in the first image. I did mean 'radiosity' incidentally, all the images were raytraced from area lights. I'm using v11.2 by the way, do you think it's worth the bother on loading v11.3, since v11.5 is nearly upon us?
David

lardbros
11-21-2012, 03:53 PM
Look at the examples again: The first example has FFX hair rendered through the glasses' lens no problem. If FFX renders fine behind transp when raytracing is used (OP said "radiosity"/"GI"/"radiosity" but guessing meant "raytracing" not radiosity), then I'm not sure ye olde "post process limitation" argument really applies here, as the post process limitation should impact both raytracing and GI similarly.

Come on!! I did look at the image, and was simply trying to help the guy solve an issue. Some of my info may have been slightly off, but the original post was confusing as I couldn't understand the difference between radiosity and GI... the same as you!... I was trying to aid the guy figure out something, and it may just be a bug!


And Rebel is most likely right... the volume FFX through a transparent object could have been done for v11... just offering some assistance !

lardbros
11-21-2012, 04:16 PM
I've tried a few things, and cannot replicate at the moment.

Is it possible to give us a few more details?


How is your glass surfaced?

What are your settings for Radiosity?

What are you surface settings?

What are your raytracing settings?


EDIT
----------------------

I see the horrible aliasing effect now... if Radiosity is on, it doesn't seem to anti-alias the volume fibers behind the glass very well, if at all?

EDIT AGAIN
----------------------

I can't get the fur to disappear using any radiosity/GI modes I've tried...

jwiede
11-21-2012, 05:36 PM
Thanks Guys,
Yes, FFX does render through glass but becomes very sketchy as in the first image. I did mean 'radiosity' incidentally, all the images were raytraced from area lights.
Okay, I don't think I understand then, what precisely is the difference between the first and second renders' settings ("radiosity" vs "GI")?

lardbros
11-22-2012, 05:52 AM
Another thing... even though I can't get it to disappear using radiosity... the horrid aliased fur (through the glass) is apparent even with Radiosity off... it's just MUCH more visible when radiosity is on.

Tried a few things to get rid of the horrible aliasing... turned on refraction blurring, which is simply ignored by the fur... turned on 'Limit Dynamic Range' just in case it was that... but it wasn't.

Trying to think of other things to sort it... but am running out of ideas.

panphoto
11-22-2012, 07:51 AM
I've tried 2 glass surfacing options with near enough identical results; 1.glass and air surfaces, 2. Dielectric material.
I've tried the various Radiosity settings, those in the samples are Monte Carlo/Use Transparency/Rays PE 4, again, no anti-aliasing behind the glass.
Raytracing settings are everything except Render Lines, Recursion 8 (though I've fiddled with that), RP 6,RC 0.01, SS & LS both 8.
By 'surface' Tim, do you mean the ffx? Thanks by the way for confirming that my problem is not random.
The 'Volume Only' button doesn't help either. David

Sensei
11-22-2012, 08:45 AM
Thanks Guys,
Yes, FFX does render through glass but becomes very sketchy as in the first image. I did mean 'radiosity' incidentally, all the images were raytraced from area lights. I'm using v11.2 by the way, do you think it's worth the bother on loading v11.3, since v11.5 is nearly upon us?
David

No, 11.2 but 11.0.2
etc. with 11.0.3
It means 2nd and 3rd service pack for 11.0.

FFX is rendering using post process pixel filter when hair is visible directly from camera.
Otherwise it's using volumetric mode, which is/should be seen by rays.
(pixel filter has much better quality)

You said first image is using radiosity, but second is using global illumination? What is difference.. ? ;)

Better- attach scene, so we can play with it..
That's always the quickest way to solve issues.

lardbros
11-22-2012, 09:07 AM
I've tried 2 glass surfacing options with near enough identical results; 1.glass and air surfaces, 2. Dielectric material.
I've tried the various Radiosity settings, those in the samples are Monte Carlo/Use Transparency/Rays PE 4, again, no anti-aliasing behind the glass.
Raytracing settings are everything except Render Lines, Recursion 8 (though I've fiddled with that), RP 6,RC 0.01, SS & LS both 8.
By 'surface' Tim, do you mean the ffx? Thanks by the way for confirming that my problem is not random.
The 'Volume Only' button doesn't help either. David

By surface, I meant the lens/glass surface... i was wondering if 'double-sided' was turned on, or 'exclude from vstack' or something. Those can really affect the dielectric shaders etc.

toby
11-22-2012, 03:05 PM
Sounds like you have Volumetric Antialiasing switched off.
( in the Effects/Volumetrics tab )

panphoto
11-22-2012, 03:48 PM
Volumetric AA was switched on. I've also tried every permutation of 'Exclude From VStack'/'Double Sided' with no obvious effect. Re the Radiosity/GI, I should have said that the first image is with radiosity enabled and the second is with just the backdrop set to white....I agree in this case, there isn't much difference aside from the complete absence of hair behind the glass! I'll try to post files over the weekend, but will need to abreviate a little. Thank you all.

lardbros
11-23-2012, 03:45 AM
Get a bug report in... and they'll let you know if it's been fixed or not! Well worth doing... certainly not a waste of time!


I know FFX has had a lot of work for 11.5, so it may have been sorted already! :D

panphoto
11-24-2012, 10:51 AM
Reported! I'll get back when I have an answer. Thanks Guy's.