Does Anyone Have This Glass Problem?

[steelers05]

I suprise myself that I keep having this problem, but does anyone else have problems with glass materials blocking out material characteristics....this image shows a better explanation of what I mean:

It seams that glass materials often block/cancel out other materials. In my scene I have a leather type material applied to the dining chairs in those "glass pods" and the same wood on the chairs that is found on wood slats surrounding the "glass pods". I also have a brushed metal texture applied to the lighting pendants hanging down in the main entrance area and a reflective wood floor. The problem is that I do now see any of these reflective characteristics that you would expect to show...does anyone know why? The glass was imported from one of the previous vray material packages and has the basic settings for clear glass. Some how, i have managed to get by on projects without resolving this issue, but I have had this probelm (where glass either blacks out things behind it or does what I am currently mentioning) when dealing with glass other times and dont remember ever really getting it resolved. I have tried searching for answers on the forums, but by now they are so cluttered with various things that I really had no success and gave up after a while. If there is anyone that thinks they know a solution or could lead me in the right direction, that would be greatly appreciated.

[steelers05]

Re: Does Anyone Have This Glass Problem?

thought i would update this, because i was able to figure out the problem and thought it may be useful for others to know....Honestly I cant believe I made this mistake, butit happens.

So do not use a refraction layer if you have flat panels of glass that have a thickness....that ends up blacking out things behind the glass...I am not sure why this happens as in real life you would think...glass is glass and the refraction happens even on flat pieces of glass. Or if you want to keep the refraction layer, dont give the glass a thickness and just make your windows or whatever you are applying a glass material to a single plane

[Jackson_cg]

Re: Does Anyone Have This Glass Problem?

So do not use a refraction layer if you have flat panels of glass that have a thickness

Or if you want to keep the refraction layer, dont give the glass a thickness and just make your windows or whatever you are applying a glass material to a single plane

Surely you mean the opposite? Glass with two faces/thickness can have a refraction layer for realistic refractions (but extremely long render times), but single faced glass must be rendered without a refraction layer or you'll get really strange results.

It actually works exactly the same as it does in the real world- it's just that it's physically impossible to have a plane of glass with no thickness, so it always has two faces (or rather two boundaries between two substances with different densities, usually air and glass).

Glad to hear you sorted this out- I was stumped what could be causing the effect when I first saw your post.

Nice render BTW, but two C&Cs- why the reflection on the sidewalk? Unless it's polished or sealed concrete/pavers it wouldn't be reflective- it looks kind of plasticky. Also, I love the tarmac texture on the road, but the tiling is really obvious.

Really nice modelling, texturing and lighting otherwise.

[steelers05]

Re: Does Anyone Have This Glass Problem?

Jackson, I dont know if I did something different, but my glass did have a thickness of about 1/4"-1/2" (cant remember the exact number) and the refraction layer was what messed it all up...it was completely canceling out all of the reflective characteristics of any of the materials that were behind the glass. I originally thought, like you, that as long as the glass had a thickness that a refraction would be fine, but that was not the case for me, and when i think about it, this has been the case for many of my past projects. So all I did was remove the refraction layer and it worked perfectly fine. I dont know why this is, and others may not have had this problem, but thats how it worked for me.

But thanks for the feedback on the rendering...I added some reflection to the sidewalk to simulate a bit of moisture on the ground. Alot of illustrations I see around have this effect, particularly for night scenes. I agree that it may not be accurate but I was trying to just create a little more visual interest. It could use a bit more work though. The road texture is for sure tiled, i left it that way with the intention of fixing it in photoshop, because I didnt have a good enough texture that was tileable for this instance and any larger of a scale would have been too much. I honestly think that scale i have it at now might be pushing it a little bit too much. But I will be posting the final shot in the gallery sometime soon. Check it out there and let me know what you think. But again, thanks for the feedback.

[jim_tim]

Re: Does Anyone Have This Glass Problem?

Steelers I get exactly the same thing with the glass. Like if I have a chrome shower head for example behind a glass plane with a thickness and refraction, the shower head will appear black in the render.

I've not tried you technique to resolve this yet but i'm pretty sure it will work seeing as it is exactly the same problem.

Just to note, I am still using the old Vray version at the moment - just in case this has anything to do with it. :-\

[foss_charlie]

Re: Does Anyone Have This Glass Problem?

I have been having the same issue. I am rendering an interior scene with a rectangular light outside the windows. The glass is a single surface and will not let any light come in. I did a little bit of research and found something on the V-Ray for Sketch Up forum and somebody mentioned that you need to check the box under the refraction layer that says Affect Shadows. They claimed this will fix the problem. I can't say that it will as I have yet to try it but I can let you know tonight.

[thomthom]

Re: Does Anyone Have This Glass Problem?

What have you set the max number of reflection/refractions to?

[jim_tim]

Re: Does Anyone Have This Glass Problem?

I'm not sure how you do this so I just assume it is set to the default :-\

[jim_tim]

Re: Does Anyone Have This Glass Problem?

Just checked under global switches and it says:

reflection/refraction

max depth 2
max transp. level 50

[thomthom]

Re: Does Anyone Have This Glass Problem?

Ah, it only does 2 reflections, refractions. Increase it until you get all the reflections/refractions needed.

[jim_tim]

Re: Does Anyone Have This Glass Problem?

thanks thom thom. I shall give this a whirl