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Glass rendering with milky white cast

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I don't understand what's happening here. If I use the default "Glass Clear RT" texture it renders with a milky-white cast.

 

Upping the transmission value in the 'transparency' shader from the default 95% to 99% seems to make it more white and less transparent.

 

Reducing that value seems to make it more transparent, as in you can see more of what's behind, but it's darkened.

 

I just want some glass that is nearly completely transparent!

 

What's going on? I've attached the VW file.

 

2051833931_ScreenShot2018-08-08at11_34_43.thumb.jpg.0fadf7883caac820795322f8531c13ef.jpg

transparency.vwx

Edited by line-weight

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Looking at your file, I think the problem is the background. The glass textures are reflecting white space. There is not much latitude with the reflections in the glass shader you could try the mirror shader instead and turn the reflections right down.

 

Better still though would be to use a really good HDR background or use the current image and load that into the Panoramic portion of the editor. It's a cheat but it may give you what you need.

 

If you just need a "backdrop", then you could make a texture from the photo and add it somewhere in the frame.

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Thanks for comments. The file above was just a test file to make sure it wasn't something weird in my main drawing. In the main drawing I'm getting that same milky cast when rendering views from the interior of a building looking outwards, so if anything is reflected in the glass it should be the interior of the building, not the background, surely?

 

 

 

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You would thinks so. In your file I turned off the renderworks background and used a stock one and the problem disappeared. I don't think its the texture. Have you tried swapping out the background for something else?

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36 minutes ago, markdd said:

You would thinks so. In your file I turned off the renderworks background and used a stock one and the problem disappeared. I don't think its the texture. Have you tried swapping out the background for something else?

 

I've tried swapping around backgrounds and you are right, it seems to be the cause.

 

There are three places you can specify a background - the 'main' background, the 'environment reflections' background and the 'environment lighting' background.

 

You'd think that it would be the 'environment lighting' or 'environment reflections' ones that would effect what is reflected in the glass but changing these has no effect - only changing the main background, the one that determines what image is seen in the background. Weird.

 

That's a bit of a pain because I'm using a specific image of the site to form the view from the windows.

 

I guess I can try loading it into the 'panoramic' type as you suggest and see what happens.

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Why not use the "seaside" image you used to make the background into a texture and apply it to a flat or slightly curved backdrop piece behind the windows. I often to that and it works well. I also noticed that you are getting the white fringing artifacts you were discussing in your posts yesterday with that background.....

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13 minutes ago, markdd said:

Why not use the "seaside" image you used to make the background into a texture and apply it to a flat or slightly curved backdrop piece behind the windows. I often to that and it works well. I also noticed that you are getting the white fringing artifacts you were discussing in your posts yesterday with that background.....

 

Yes, the fringing artefacts are there again. I've just tried loading my image into a panoramic background - it's all out of scale and orientation - but the white reflection/cast has gone, and so has the white fringing.

 

I wonder if this means there's some kind of bug with the 'normal' image background?

 

I'm going to see if I can get it to work as a panoramic background with a bit of trial and error to work out the right size, orientation etc.

 

If that doesn't work maybe I will try your suggestion. But don't you then run into problems with that backdrop object being subject to the effects of directional lighting, and so on?

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9 minutes ago, line-weight said:

But don't you then run into problems with that backdrop object being subject to the effects of directional lighting, and so on?

Not if you make sure the texture is set to not cast or receive shadows.

Edited by markdd
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12 minutes ago, markdd said:

Not if you make sure the texture is set to not cast or receive shadows.

 

Ah right, got you.

 

I think I've managed to make it work as a panoramic background though. Everything in these two renderings is the same except that the top one uses a 'normal' image background and the lower one uses a panoramic image background. Milky glass problem solved - thank you.

 

1790215172_ScreenShot2018-08-08at15_59_57.thumb.jpg.e9400efa8c6f97f06668ebe2bc464066.jpg

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12 minutes ago, line-weight said:

 

Ah right, got you.

 

I think I've managed to make it work as a panoramic background though. Everything in these two renderings is the same except that the top one uses a 'normal' image background and the lower one uses a panoramic image background. Milky glass problem solved - thank you.

 

1790215172_ScreenShot2018-08-08at15_59_57.thumb.jpg.e9400efa8c6f97f06668ebe2bc464066.jpg

 

@Jim Wilson you do a lot of rendering... should the type of image background you assign if its only an image really make this happen?

 

Kevin

 

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2 minutes ago, Kevin McAllister said:

@Jim Wilson you do a lot of rendering... should the type of image background you assign if its only an image really make this happen?

 


At first glance this milkiness seems broken, but I will pull this file and take a closer look soon, got some things to wrap up first.

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