window glass question

[markf]

I have just started with Vray, going through tutorials and applying to my own test scene.

 

I cannot figure out why the glass material blocks the view of the distant background. It's a Vray material. No doubt some lack of undestanding on my part. Can anyone point me in a direction to fix this?

 

Also interested in any comments on the general lighting so far.

 

Image attached

 

Thanks!

[JamesTaylor]

it looks as if you have a couple of panes behind each other since the door is slid open... i'd image that in your material settings under the refraction section you need to increase the max depth value....

 

having said that i have just noticed you can still see the verander and railing but not the background? try adjusting the max depth value, if it doesn't help post your material settings too.

[markf]

Thank you for your reply. I increased the refraction max depth to 50 with no difference in result.

 

Attached are some of the settings, I'd glady post anything else that could help trouble shoot this.

 

It is odd that the deck and railing are visable and then the occlusion starts.

[Brian Smith]

Looks like you have 'Visible to Reflections/Refractions' option disabled in the Object Properties dialog box or the 'Visible to Refractions' option disabled in the VRay Properties box.

[markf]

Brian,

 

Thanks for your reply.

 

Neither of the options you suggested are disabled in the respective properties dialog boxes.

 

I was reading on the chaos forum about this:

http://www.chaosgroup.com/forum/phpBB2/viewtopic.php?t=18061

 

I tried "making the glass invisable to GI" and also hiding the glass, calc the IR map and save to file, turn on glass and render with saved IR map. None of this worked.

 

I'm trying to keep the glass reflecting the chair but still see through to the background. Can't figure what I'm doing wrong.

 

I was going to post this to the chaos forum as well. I can log on and am registerd but when I try and post a new thread I get a "feature reserved for special members" type message. Is the forum limited to posts by select people?

 

Thanks.

[jfs]

Hello Mark,

 

if you pretend a clear glass for start, and assuming the glass will be visible in the scene, why are you using 0% (black) reflections? I can be wrong but I think clear glass has no diffusion (= 0% black), can be 100% reflective (althout an almost white value sometimes works better) and should be 100% refractive (if you want the light to pass trough). Usualy I use a IOR value between 1,53 and 1,57, and you should try turn on Fresnel Reflections (or even better apply a Falloff Map to Reflections with Fresnel Falloff). Hope this can help.

 

Sincerely

Joao

[sterealkey]

@ Markf

 

Set up your material as follows.

 

Diffuse - 100% black

 

Reflection - 100% white, and switch on fresnel reflections.

 

Refraction - 100% white, IOR - 1.6 (but this should be the default setting anyway)

 

I'm almost 100% positive that this will fix your problem.

 

 

Peace.

[Nic H]

Is the geometry correct? Not a single face?

If you set up the mat like sterealkey says it should render fine?

[markf]

@ Markf

 

Set up your material as follows.

 

Diffuse - 100% black

 

Reflection - 100% white, and switch on fresnel reflections.

 

Refraction - 100% white, IOR - 1.6 (but this should be the default setting anyway)

 

Thanks for your reply.

 

I changed diffuse to black - no difference in rendering

 

I changed reflection to 100% white and turned on Fresnel reflections - this gives essentialy the same result as I had with my material setup. See attached image

 

nicnic,

 

I had thought it might be geometry so I made a new object for one of the panes of glass. The originals are just simple, thin, editable meshes. I made a rectangel and extruded to 0. That renders as all black. If I give it some thickness it behaves like to original glass. If I delete the back vertices of the original glass, so it has no thickness, it also renders black.

 

I'm trying to get slight reflections and see through to background. Any more suggestions greatly appreciated. I'm new to Vray and am struggling with this.

[erickdt]

What it probably is is the reflection/refraction/enviroment checkbox in the enviroment rollout of VRay. I would turn it off or try turning off the "override max" box (this is all of course assuming that your background image is in the enviroment slot rather than a plane with a material mapped on it which might also solve your problem). Good luck!

[erickdt]

And BTW the lighting looks nice. It's good to see that you got VRay there's already a huge improvement in the realism of your work! You'll grow to love it, trust me.

[markf]

Erick,

 

I think, like you that the problem is somehow environment related. I have none of the boxes selected in Vray environment. I had Max environment background color on all white. Changed it to all black and the glass renders black (vs previous grey).

 

My background is an image mapped to a plane. I tried moving the plane between the rail and the glass. This results in the same thing. I can see the rail but beyond is black. Weird. I can't figure out what I've done wrong.

 

Is the "overide max" in the Vray envronment rollout? I have none of the boxes chaecked there.

 

Thanks for your help.

[erickdt]

In that case I might try the override MAX option in the VRay enviroment rollout.

[markf]

Ok,

 

A helpful person on the Vray forum figured out what I had done wrong.

 

I had "visable to reflection/refractions" unchecked in the object properties for the background plane.

 

Wow, that ran me around a bit.

 

Thanks for all of your collective help.

[Brian Smith]

Looks like you have 'Visible to Reflections/Refractions' option disabled in the Object Properties dialog box or the 'Visible to Refractions' option disabled in the VRay Properties box.

 

I've never quoted myself before like this, but when i posted this, you said that they these options were not disabled. I don't get it.

[markf]

Brian,

 

So you did.

 

1,000 apologies!! I thought you were refering to the glass objects vs the background plane.

 

I am very sorry I misunderstood. My bad.

 

I started learning Vray with your article in the Vis. Insider tips. I have also got the book you wrote and have signed on for the online training for Vray. So I of course was psyched when you replied. Sorry for not thinking more clearly.

[alfienoakes]

How is your background created in the scene. Is it a plane with an image mapped on to it?

 

If so, and I dont think this has been suggested, in the properties of your background plane you have probably unchecked "visible to GI" etc and a few others, to control the visibility of your background.

 

Select the background, right click and go properties. Then, in "Rendering control" look thru the options there.

 

Make sure you leave "visible to reflection/refraction". Otherwise you wont see it. Your glass has refractive properties, so as you see thru the glass, everything that is not visible to refraction, will not be seen..

 

Andy

 

P.S. Damn my not looking!! Just noticed there is a page 2 and an answer!!

[alfienoakes]

Regarding my previous erm.. answer....

 

I am sort of glad though, as it was what I thought..!! Well done Brian.. and good luck with Vray Mark......

[markf]

thank you Andy!

[only3d]

mark, eventhough u solved your problem i still think there is something wrong in what youre doing..

using a plane for background is not the way to go, 1st- well u saw for yourself its just another thing that can mess u up, 2nd- it could block the GI lighting that comes from the outside plus it can cast a shadow onto your scene and so on. well yeh u can fix its properties to ignore your light source and what not which brings me back to my 1st point.. (what a loop )

 

ull be better off placing your back' image in the environment slot, of course using the vrays 'override envrironment' option.

 

good luck further on