Glass no render!

[ShaunDon]

Hey guys. Here's the deal.

I've been banging my head against my desk for over two hours now trying to figure out why the hell I'm not getting this VRay glass material that's been in my library for well over a year, used in dozens of projects, to work in this particular scene. It's a pretty straight-up glass that renders fine if I merge this object into a new scene, but I can't figure what it is about the settings I've got that makes it no-worky in this one.

Here're the glass settings...



And here's what the sucker looks like:



Isn't that awesome? I've turned the reflections to practically black, refractions to pure white, and the best I get is hazy crap. If I crank the reflections up enough to see them, any transparency (of which I can never get more than maybe 50% no matter what I do) completely disappears. Just plain weird.

The only thing different that I've done with this scene is that I'm trying to use logarithmic exposure control for my exterior daylight scene. Screwy that even when I turn it off it doesn't make a difference.

Anyway, if there's anyone out there bored tonight who wants to make an ass out of me and find the missing checkbox that I've yet to check, you'd be my personal god and savior.

Here's the scene file with just the glass from the canopy... I rendered the image in this scene to make sure it's still doing it.

http://www.shaundon.com/glass_no_render.max

Thanks all.

Shaun

[Gijs]

max exposure control is causing all the trouble.

[ShaunDon]

That sucks. I was hoping I wasn't gonna have to scrap my lighting. Figures though. I was just too excited when I read logarithmic exposure worked for VRay.

[RErender]

it will work if you are reflecting/refracting geometry, I have had good results mapping my environment to a dome that is invisible to GI.

[ShaunDon]

I've been able to get reflections working on the glazing as long as I reference the same HDRI map that I'm using for the environment (which I've had to multiply up to 20 or so to get it in range with the IES sun) ... but the same didn't work when I tried it with the transparent glass material. I can get it to either partially transparent with no reflections, or solidly reflective and fully opaque.

I can spare a bit more time tomorrow to try and resolve it, but we have to go into production on this tower shortly so I'll have to scrap my exposure control experiments for the time being if all else fails.

Thanks!

Shaun

[Gijs]

One other thing, if you use max's exposure control you have to set your colormapping to linear

[samuel_bubat]

hmm.. you said you have the same problem with and without logarithmic
exposure control !? But You didn´t accidently activated the
"override reflection/refraction" option wich is by default black.. like you glass !! ?

[ShaunDon]

Nope, all my overrides are off, and I can get it to reflect if I put the HDRI multiplied to 20 in the environment map, but the refraction controls for some reason are way out of wack... even at with the color at pure white, the best I get is 50% transparency.

I've left color mapping alone, so it's still defaulted to linear 1,1.

This just really makes no sense to me. Of course it has to be the exposure control's fault -- it's the only thing I'm doing differently, and it's a major change -- but all the maps it's reflecting should still be in the visible range. If they're not multiplied, then of course they're practically black to the glass so nothing reflects, but what then would cause the refractions to be all funky?

I got really excited when I read this thread last week...
http://www.chaoticdimension.com/foru...ic.php?t=10323

But perhaps it's not ready for primetime? All my reflections, glossy and otherwise, work great so long as I have a solid material. I guess my only option if I want to keep these settings is to strip out exposure control in a separate file and render my clear glass in a separate pass.

Shaun

[paulison]

maybee im an idiot or something (i dont use fog much) but shouldnt the multiplier be 1.0 instead of 0.1? the settings look like theres a lot of fog in the glass. I was thinking that refractive glossies would have to be lower than 1.0 to effect this but you never know? Im pretty sure there were some changes to fog recently, maybee someone else can elaborate

BTW: ive spent the last 4 days trying to get a scene to render decently after insterting some objects....I forgot to delete an imported omni that came with one of them! (I didnt see it) So yes I am an idiot who overlooks the simple things.

[RErender]

Like I said it will work as long as you are reflecting
efracting geometry. Here is an example. Notice the black glass rail in the first image. The second has a background card and the glass is correct.