Stacked glass material

[perolalars]

Re: Stacked glass material

Hi Emil
About the work, I was referring to Andy that he suggested to cut away the "interior" of the pane to not have so many refractions, at least I thought he was?
And is that what you are suggesting to? Cut out the "interior" of the glass pane? But correct me if I am wrong, will I not end up with an interior edge also? Dont that causes more refractions?
I havent been able to recreate your great test of my idea...
I cant get it to work at all :'( . My tries look like sh-t.
Are you using hdri? Lights? Sun?
My idea is a big pile (1500x800x300mm) of stacked glass panes with an edge (like your testrender) and in some places in the interior of the panes there are "cutouts" with waterjet, a straight line, building together symbols like a fotprint, a fish or other details...Hope you can see this.
Of course the "images/details" will be visually distorted but thats ok.
Its a sculpture for a church and I really need some images to present.
But I cant get it to work.
Do I sound desperate enough???
Could you explain how (from start, all included) you did the test render.
Regards
Per

[fooprobe]

Re: Stacked glass material

Yes, i was following andy's line of thinking, or trying to. If i understood him correctly, he was suggesting to build the stack as a single solid to reduce the number of surfaces. Im not sure about what removing the "interior of the pane" means, maybe I misunderstood Andy. I'm also not entirely sure this would give you the effect you want though, it's just a workaround.

Maybe you could post the model, or at least screenshots of it.

My test render was no lights, just hdri, I used one of the free ones from Aversis in both gi skylight and background, no adjustments just defaults, no vray camera. I think the hdri was the "balkon_sun" or something. You have to move the camera around until you get an angle that you like, eg the reflection.

Hope that helps...

[perolalars]

Re: Stacked glass material

Hi Emil
Here is a screendump of a starting surface..
I was actually starting in the other end trying to figure out how to render then create the object.
Anyway, the glass is supposed to stand on its "bottom edge" and then stacked along the longside as in screendump2
As you can see the edges is facing upright.
The fish is waterjet cut into each pane right trough the glass (there is more details coming...
But I cant get the box mapping to work, so plz what size was the glass pane, you used, in relation to your bump map, and was it a bump or a displacement map?
Any hints are great
Per

[perolalars]

Re: Stacked glass material

And I forgot: how did you make the material ? in detail that is.

[fooprobe]

Re: Stacked glass material

So you already have a solid. And it looks like you're doing vertical slices (sorry, in on my mobile, can't see too well). I think you're going to have to actually cut this into individual slices and pull them slightly apart like I originally suggested, I don't think a "workaround" as Andy and I were suggesting is going to work on this, because the edges are meant to seem like they are part of a continuous surface.

As for the material and box mapping, I don't think I can describe that better than I have already. Can you describe what's not working in yours? You can start just by using the map I posted. Except that because your slices are vertical, you'll need to rotate the box mappin so the smooth sides are on the large sdes intead of top & bottom. Either rotate the widget or build the map differently in photoshop.

[perolalars]

Re: Stacked glass material

Hi Emil
Yeah and no about the solid.
Its similar but its not the final object, but it works for you to get an idea what I am doing or aiming for...
But it dont matter the orientation of the piece.
Its meant to be glued together with UV-glue for outdoor applications.
I´ve started to get some result with rendering one pane but when I copied that one and put it ontop of the first one I went from 30 sek to 9 min render time. Do you have some idea to cut that number?
Many thanks for your patience
Per

[fooprobe]

Re: Stacked glass material

That's a little odd. If you delete the copy does it go back to 30 sec? What if you delete the original? Did you change that max depth setting? Is the longer rendering spending more time in the prepare or in the render pass, or is it even?

[andybot_cg]

Re: Stacked glass material

Yes, I was suggesting to do one solid, whether it's union of the individual panes or you just model the edge condition on the underlying model. Seeing now how many stacked pieces of glass there are, I can't imagine you could render it in any reasonable speed with that many refractions to calculate. So my suggestion is - for simulating the stacked glass effect - put individual planes where the panes intersect, and make a new glass material for it with a refraction of 1.0 This way you will get the reflections that stacked layers of glass would produce (and I would limit the depth of the reflection to probably just 2 or 3)
With a single pane - if you had regular glass refraction, it would bend the light way too much since there isn't a corresponding double surface to bend it back. Hope I am explaining it in a way that makes sense.
I haven't tried it, so it may not come out, but that's my best guess.

Andy

[fooprobe]

Re: Stacked glass material

great idea!

it may not even need a reflection layer - i'm getting very similar results with a material that just refracts.

[perolalars]

Re: Stacked glass material

Happy to have you guys
Its monday morning again and must go to work in my studio...
The new material I have, dont give me that increase in time, but it dont look as good as Emil´s
And I use your (Emil´s) bump map. So any tip on making it look better. Would it be possible to send the .vismat?
I know I have to make other bump maps for the other panes.
When I got rid of the infinite plane the time went down, but I cant understand the strange interference in the render, it dont matter how I position the camera?
Andy, when you talk about depth of reflections do you mean the subdivs in the reflection layer.
I haven't tried the plane between the panes yet..
Thanks a million

[deanfitton]

Re: Stacked glass material

hi,

firstly is that image two panes of glass? if so they are clearly exactly the same, have the mapping position slightly different on each edge, that will make them look more random.

in regards to the reflection/refraction rate... its under the global switches rollout in the options editor. its default is probably between 2-5 depending on the release version you have. to calculate the value you will need it will be the amount of surfaces you will be looking through... so if you stack 10 panes of glass, each with 2 surfaces, you will require a value of 20. but id probably set it to something like 25 in that senario.

its been said previously but make sure there is a tiny gap between each pane.... something like 0.0001 mm otherewise you will get discrepancies.

hope this helps

[fooprobe]

Re: Stacked glass material

The weird look of the background is probably because you have the background mapping set to spherical instead of mirrorball. Do th same for gi.

EDIT:
As for the bump, it looks too bumpy, reduce the multiplier, and it looks to squished in the z direction (looks like it is repeating) - try increasing the size of the mapping in z.

As deanfitton says, you may want to adjust the map for each "slice" - I took that original bump from your original image, just cropped, desaturated, adj perspective, adjusted levels and blur, it would be easy to get more from there ... Actually you might be able to take the entire stack and use that.

The rendering is looking good, keep it up!

[andybot_cg]

Re: Stacked glass material

I was actually thinking less reflection/ refraction would be better - as it would speed up the render. This is the setting in the global switches tab. (default is 5)

[andybot_cg]

Re: Stacked glass material

OK - I had a chance to do some quick renders of how stacked glass material behaves. (I used the vray default render settings)
1. the interior pane, even if made with 1 plane should have the same index of refraction (I stated it incorrectly earlier) Also, I used reflect/ refract depth of 5.
2. I get a better result in terms of rendering quality with the separated planes.
3. times for single interior plane versus time to render glass separated by .75mm was about the same.
(The glass in my test is 40cm thick, no reason.)
4. time to render with refract depth 3 was slightly faster.
5. One more option I did was reflect/ refract depth of 10. It doesn't appear much different, but certainly takes longer (I tweaked the fog color on this one, shouldn't be a factor though)

Thus - the render time shouldn't be much longer for the separated panes but gets you a more accurate result.

Andy

single plane

separated planes

and reflect/refract depth of 3

reflect/ refract depth 10

[andybot_cg]

Re: Stacked glass material

Whoa, so I scaled the model to a more realistic glass dimension, and my render times shot way up. Here is a render with 4cm glass, 175x200cm panes.