Stacked glass material

[perolalars]

Hi
I have tried to make an ordinary glass material to simulate stacked glass, but its just wont work.
So how to make, say a block of stacked glass with the appearance of 10mm thick glass panes stacked on top of each other.
It is not supposed to be panes with polished glass edges just cut with ordinary glass cutters.
As in the image on the right hand side of the stack.
Any hints are welcome
Thanks
Per

[fooprobe]

Re: Stacked glass material

- when you make the model, separate the stacked objects by a tiny amount so there aren't any overlapping surfaces. you probably should adjust each piece so the vertical stacking isn't literally perfect.

- you can get the green effect using the fog color and multiplier in refraction settings

- make sure "affect shadows" is on in refraction settings

- you may need to increase the refraction and reflection max depth and max transp. level in global switches, depending on the number of pieces being stacked

- use a bump map or displacement map to get the slight warping in the cut edge

- note that in your image, one side is green and the other is much brighter - this has to do with the surrounding objects, lighting, etc.

[perolalars]

Re: Stacked glass material

Hi Emil
And thanks for reply
Yeah the overall material is no issue but its the egde of the pane I cant handle. Should I separate the edge and the pane itself? How ever to do that?
- you may need to increase the refraction and reflection max depth and max transp. level in global switches, depending on the number of pieces being stacked
Could you be more detailed what you mean?
- use a bump map or displacement map to get the slight warping in the cut edge
How would that bumpmap or displacementmap look like? (sorry for stupid question) cloud or what ,Photoshop
- note that in your image, one side is green and the other is much brighter - this has to do with the surrounding objects, lighting, etc.
Yes I know, but its the right hand side look I am after....
Regards
P

[fooprobe]

Re: Stacked glass material

try using the noise map (instead of bitmap) in the material. you can probably do this just with a bump map. use the "size" parameter to adjust the xy (uv) scale of the noise, and the multiplier to adjust the apparent height of the bump.

the max depth and transp. level in global switches control how many bounces of light contribute to reflections and refractions. usually the default values are ok, because there aren't too many bounces, but with a stack of glass, you may notice weird dark areas in the refractions. you can adjust these values to make them better, but render time will increase. but if you're just worried about the edge, maybe this is overkill - by the time you put a bump on it, you won't really see much of a difference.

[perolalars]

Re: Stacked glass material

Ok
I will try this, but its not just the edges of course. But since that is the "opening" of the glass-surface (where you see into the glass) I thought that its of significance that the edge are "correct".
I hope to make some "indents" or sandblasted "prints" in the glass-surface that will reflect trough the glass, visible in some strange refracted way....
But thanks

[fooprobe]

Re: Stacked glass material

so i tried noise, and it may be a little too uniform. i grabbed a part of the glass image you sent and turned it into a bump map:



and it works ok. needs to be modified a little. since you don't want it on the top and bottom surfaces, you'll have to use box mapping with divided texture space and a different map:



looks like this:


if you work it you should be able to get what you want this way

[andybot_cg]

Re: Stacked glass material

Per,

I think I see what Emil is explaining - you separate the groups of glass (each pane in its entirety), not the edge from the surface. If you have the large surfaces touching each other, you will get weird dark areas in the refractions.

Emil- that's a nice map you came up with!

Andy

[fooprobe]

Re: Stacked glass material

thanks, andy - and thanks for clarifying my post for me! right, each pane or "box" of glass needs to be just a little separated from the one below and above. each pane should be a solid so the refractions work right, but doesn't have to be box shaped.

btw on that render i didn't muck with the max depth etc settings, you'll prolly be fine with default.

and it doesn't show well unless you download, but the right hand side of the "divided" map is blank white, so the top and bottom of the glass is smooth.

[perolalars]

Re: Stacked glass material

Hi Emil and Andy
Great, I like it. Thats just what Iam after.
But I dont really understand how you get the bump map applied just to the edge of the pane.
I little bit slow I suppose...

[fooprobe]

Re: Stacked glass material

you make a single image that is a composite, from left to right, of each image you want for each side of the box in the following order: front, right, back, left, bottom, top

then apply a box map and select the "divided" texture space, instead of "single"

rhino will divide the image into 6 equal areas left to right and use one area for each side of the box, in the above order

that's why my second image has the same bump repeated four times, with a white "image" repeated twice

see the following link for more info, scroll down for box map
http://www.rhino3d.com/4/help/dialog...uremapping.htm

[perolalars]

Re: Stacked glass material

Many thanks Emil for your patience with a knob
Total newbie in mapping so have to learn that to I asume..
Weekend cut out for you..
Cheers
Per

[perolalars]

Re: Stacked glass material

Emil or someone..
When I want maybe hundred of stacked glass panes on top of each other, what is the best solution?
Because I noticed when just copying one pane with box/divided mapping on it, the rendertime just went much higher?
And can I still use box/divided mapping if one ("the front") side is curved or wavy?
Per

[andybot_cg]

Re: Stacked glass material

I wonder if you would get the same effect if you modeled just the edge and not have all the planes in the middle. Could be that processing all that refraction eats a lot of CPU time? Draw a big box and draw only the jutting glass edges? (Maybe with a fog color, you would be able to get the green effect?) Just some thoughts
Andy

[perolalars]

Re: Stacked glass material

Hi Andy
Thats a lot of work, and I want to make some cutouts in the panes to so that's not an option I think.
Are there no workaround to achieve the same effect with the glassedges?
Every pane is individual with a wavy front but with a square back.
Per

[fooprobe]

Re: Stacked glass material

It's not that much work. Stack the planes the same way you would have anyway, but this time make sure they *are* touching top to bottom. Then union them into one solid. The union will take a while with a large stack, you're better off doing a few at a time. Also, since you'll end up with a much thicker object - 100 times thicker - you'll need to tone down the fog multiplier a lot. And you'll have to make sure to repeat the box map vertically to keep the scale right.

I'm not sure what you mean by cutouts, but these could all be unioned into the final solid.

Yes, box/divided will work with a curved edge. The more the curved edge diverges from being a true box, the more distorted the mapping will appear, but you can tone it down in the bump map for that side. And you want distortion anyway, so maybe it'll be fine.