transparent window issue?

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transparent window issue?

hi guys, i'm having a bit of a problem with getting windows to be transparent.

this model is from sketchup, and the window is composed from two layers of a 5% opaque material.

when i import the 3ds file, everything looks great in the openGL page. i can see through the windows from either inside or outside.

but when i render the windows, they are only transparent from the outside in, and if i add a background .jpg, i can't see it through the windows (from either direction)

i have edited the window materials to 1.00 transparency, as well as adjusting the color opaqueness to 0%.

the only way i can get the image to show through the windows is to erase the glass material entirely, which is not a good solution when i want to render them with a bit of reflectivity, raytracing, etc. etc.

i searched the forums and i can't seem to find a solution anywhere. i also messed around with the alpha channel settings to no avail; though to be honest, i'm not quite sure what that is all about anyway.

i am very much a rendering n00b, so please go easy on me:D

since i can't enclose the .jas, or .3ds file, i hope i have managed to make my problem clear (or at least clearer than my windows LOL)

cheers, and thanks, chuck
 
here are two quick .jpgs of what i am talking about.

the first show that you can see through the windows from outside into the model, but you can't see the background out the other side.

the second shows the gray squares you see from inside out.

these were rendered with no adjustment of the material settings, just straight from the 3ds import. no adjustment of any setting i have messed with helps at all.

please help!!!

thanks, chuck
 

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kannonbal said:
but when i render the windows, they are only transparent from the outside in, and if i add a background .jpg, i can't see it through the windows (from either direction)
Click to expand...

Chuck,

At this time, you can only use the HDRI tag with either a .hdr image or a .jpg image to do what you want. Keep in mind the fact that, in pano mode, the image has to be equirectangular. And then you should be able to view from either side without deleting the glass ... ;-)
 
hey fused, thanks for the response.

i definitely had the export two sides option turned off in sketchup, when i made the 3ds file.

i also tried to erase one of the two window pane materials and it still won't go transparent from the inside out.

i am enclosing the .3ds file, in the hope that that helps.

cheers, chuck
 

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Francois said:
Chuck,

At this time, you can only use the HDRI tag with either a .hdr image or a .jpg image to do what you want. Keep in mind the fact that, in pano mode, the image has to be equirectangular. And then you should be able to view from either side without deleting the glass ... ;-)
Click to expand...




oh, i was under the impression that the hdri tag only worked with .hdr files.

so i don't load the background in the camera background location.

i'll try this right now. thanks!
 
well, we are definately getting much better, thanks francois!

i can see throught the windows, whoo hoo!

now how to get the model to be placed exac tly where i want it in the hdri? it seems like i am not getting part of the .jpg in the final render.

also, the resolution of the .jpg, which is great as the camera background, looks really fuzzy and as if it has lost a lot of detail when it became a hdri tag.

is there anything i can do about this?

i am trying to actually mimic a view from the great room for my client, so placement is crucial. i could nail it when it was a camera background, but i'm not so happy with the hdri result, though it sure beats a gray square!

cheers and thanks, chuck
 
kannonbal said:
well, we are definately getting much better, thanks francois!

i can see throught the windows, whoo hoo!
Click to expand...

Good ! Ask and you get an answer ... :) As a newbie you have a lot of privileges ... :cool:)

kannonbal said:
now how to get the model to be placed exac tly where i want it in the hdri? it seems like i am not getting part of the .jpg in the final render.
Click to expand...
- You can rotate the hdri image (see the tag parameters)
- Play with the camera FOV parameter (this will zoom in/out on the background. Play then with the scale of the model to fit the background
- But again your hdri image (or jpg) should be equirectangular ( 360° H x 180° Vertical ) otherwise you will warp your backgroud image
- If your existing background image comes from only one shoot of your digital still camera, you're out of luck ... ;) since this is not enough (not covering your 360° horizontaly
- Do a search on G..gle for HDRI and you will get a lot of background information to understand what I mean

kannonbal said:
also, the resolution of the .jpg, which is great as the camera background, looks really fuzzy and as if it has lost a lot of detail when it became a hdri tag.

is there anything i can do about this?
Click to expand...
See above. Very likely your still image is "enlarged" to cover the 360°. But without seeing, it's difficult to be sure.

Hope this helps


One thing I forgot to add if you have a single shot still image :
In your case, you can fake a 360° image that's needed by the tag by modifying your existing image since you only need to look through the windows. Use Pshop or similar to add empty space around your image. Final image should have a 2/1 ratio. Then use the rotate function to position it.
 
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francois, you are awesome. thank you so much for your detailed answer.

of course, you nailed it. i'm trying to use a single image from my digital camera. obviously, i've got warping background issues. i'm off to photoshop to get my 2:1 ration and see how that works for me.

results to follow........

chers, chuck

and thanks again
 
oh yeah!!!!:p

francois, i am forever in your debt!

changed the canvas size for my .jpg to get the 2:1 ratio.

adjusted the scale of my smart folder to suit.

most excellent!

next time you're in montana, i owe you a beer:D

cheers, chuck.
 
thanks to francois, here are a couple that i am willing to put forth for comments.

what do you guys think?

i'm still messing with the scale of the model to get the hdri just right, but i am getting much closer to the actual view.

any suggestions on improving the window glass?

and i'm sure that i am not alone with wishing that i could get tiled textures to look a little better.

the model was done in sketchup and exported as a 3ds. i'm wishing, too, that i did my logs with more segments to assist in my textures looking a little better.

and i can't lie, there's a bit of post rendering clean up done in pshop....


all comments appreciated and welcome; don't hold any punches!

cheers, chuck
 

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Chuck,

kannonbal said:
any suggestions on improving the window glass?
Click to expand...
Try a pure white transparency color and transparency intensity at 0.9 or 0.95 to start with.

kannonbal said:
and i'm sure that i am not alone with wishing that i could get tiled textures to look a little better.
Click to expand...
There are a lot of sites with nice free textures. Here are 2 :
http://lemog.free.fr/lemog_v5/index.php?cat=4
http://www.accustudio.com/exchange/textures.php?dir=wood
You can also play with bump maps and the UV scale in the Material properties.

I think I would also use soft shadows. Are you using a radiosity tag ?
 
Nice model! Concerning the glass, you can put in some reflection. And try rendering with radiosity tag to your camera.

Regards,

Peter
 
hi guys.

the window material transparency is set at .95 right now, and i set the color to a white with 5% opacity. i also have the reflection intensity set at .05, which might not be quite enough. i think i am screwing myself by using 2 layers of glass, like a real window, instead of just one for the renderings. i'm going to erase all of the outside layers of glass in the model, and see if that improves things any.

i am using a radiosity tag. i have it set for ambient occlusion, with an intensity of 1 and samples set at 800. i also set the error to .1.

you guys think that i should set it to actual radiosity? i was trying to keep the render times down a bit (2500sec already) until i was happy with everything else. and francois, is the diffuse scattering setting the best way to soften the shadows, or do you just reduce the intensity.

FWIW, i also threw in a caustic tag just to see how that worked, and i'm not seeing any noticable differences anywhere. htough the windows would be the only place where anything would show up any way, i guess.

and i never even thought of messing with the UV scale.


thanks for the input! it's much appreciated. i wish you could see the 5 meg .tiffs; they do look better than these tiny .jpgs:) and thanks for the texture links.... francois

cheers, chuck
 
i am using a radiosity tag. i have it set for ambient occlusion, with an intensity of 1 and samples set at 800. i also set the error to .1.
Click to expand...
Ambient occlusion doesn't render refracted surfaces so you'll need to use the render tag on the glass objects and disable radiosity.

FWIW, i also threw in a caustic tag just to see how that worked, and i'm not seeing any noticable differences anywhere. htough the windows would be the only place where anything would show up any way, i guess.
Click to expand...
Check out the manual it covers setting for caustics. There's also a lot of useful stuff on the forum about caustics.

Andrew
 
thanks andrew.

haven't tried render tags on specific polygon objects, yet. i just read the help files concerning the render tag, after reading your post, and it is all starting to make sense. plus, anything to reduce the full radiosity render times would be great.

one other thing i am fighting is how to make a painted wall glow, as if it were painted with a gloss or semigloss paint, without making it too reflective.


i still have plenty of learning left, but i am well pleased with the improvement i am seeing from week to week. cheetah is a wonderful complement to sketchup and photoshop. just excellent.

here's one of my most recent
cheers and thanks again, chuck
 

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Another tip for interiors is to have the sun shine through the windows. This creates nice shadows and lights your interior in a more natural way I think. For the kitchen, I would put in a ceiling and also try to let the sun shine in. You can create a sun with a distant light or if you have a powerfull computer, use an arealight that produces nice soft shadows. Have a look at this Post.
 
thanks guys for the input! always appreciated!

i actually have a spot light shining throught the window to simulate the sun, but i think that a distant, or area light would be better that what i am getting. thanks for the post link.

well, it's off to calgary for a few days of business meetings before i can get back to the renderings. can hardly wait.

and is a macbook pro powerful enough for the area light to work right? 2.1 gz processor with 1 gig of ram?

cheers, chuck
 
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