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Transparent materials on white backgrounds

Posted: Thu Feb 24, 2011 6:18 pm
by RobMitchell
Hi everyone. I'm just looking for thoughts on something that's been on my mind for a while: getting a good looking image from colourless transparent materials rendered on perfect white backgrounds. Phew...

We've been asked to do various product shots over the time we've been using Maxwell and have always gotten great results. What clients generally want/request is a perfect white studio setup which is fine for the majority of visuals, but when it involves an acrylic or glass object I sometimes struggle to get a good looking final result. Especially when said object is on it's own and the main focus of the render.

When rendering these objects on dark backgrounds or with other parts, the results are instantly amazing. Obviously darker backgrounds allow you to see the highlights and reflections/refractions to their fullest, whereas rendering them on white naturally tones down a lot of that stuff. My initial thoughts were to render onto transparent and use the alpha channel to place a white background on in post, but this often gives a more "dull" end result lacking the detail you see when it's on a dark background. Or, as clients have said, they need it "whiter" behind the actual plastic area.

Here are a couple of examples of an acrylic object I might typically be rendering. It's nothing too fancy in both detail and render set up, I created it just now to test rendering options. The scene is just the product floating with IBL, apart from image 3 which has a white backdrop as well as the same IBL. Each render had about 15-20 minutes to cook.

Image 1 / Acrylic rendered on black.
Image 2 / The same image with white background added in post.
Image 3 / The same scene rendered directly onto white. (Didn't have time to let this go longer, but hopefully it gets the point across.)


Aside from cutting the images out, no postwork has been added to these as I wanted to show raw results.

Image Image
Image

So essentially all I'm wondering is, how can you get the dynamic look image 1 but on white. Although I like the result of image 2 personally, we often get comments on that technique not looking as they'd want it. I'm sure there are better material and scene setups than I've tried (although the acrylic material I'm using looks incredible generally), but I'm finding it difficult to solve the issue. Is post-work the answer? I'm continuing my tests when I get time, but any tips or techniques would be great too. Thanks!

Re: Transparent materials on white backgrounds

Posted: Thu Feb 24, 2011 7:02 pm
by tom
Are you sure you're using the same map in IBL reflection/refraction? I doubt...

Re: Transparent materials on white backgrounds

Posted: Thu Feb 24, 2011 7:40 pm
by RobMitchell
tom wrote:Are you sure you're using the same map in IBL reflection/refraction? I doubt...
On that 3rd image? I am, but like I say there's a white backdrop behind it. It's all just testing and getting ideas out in those images mainly.

Re: Transparent materials on white backgrounds

Posted: Thu Feb 24, 2011 7:43 pm
by Half Life
maybe switch the backdrop to 225 white and adjust in post.

Best,
Jason.

Re: Transparent materials on white backgrounds

Posted: Fri Feb 25, 2011 12:41 am
by Mihai
You could maybe just have a much whiter version of your hdr for the refraction channel. Just create a lighter version in PS of the hdr and resave it also as an hdr.

Re: Transparent materials on white backgrounds

Posted: Fri Feb 25, 2011 2:16 pm
by RobMitchell
Thanks a lot for the tips guys. I'll put them into practise as soon as. :)

Re: Transparent materials on white backgrounds

Posted: Fri Mar 04, 2011 1:53 pm
by RobMitchell
Had a bit more time to play with some settings and ideas last night and generated a render that is just what I was looking for. And with no post work. :D

Image

It's all going to be part of a product animation as well so it should look great when moving around.

(For those wondering, it's the "hopper" found in some water filter products. Here's how the solid model looks.)

Image

Thanks again for the tips!

Re: Transparent materials on white backgrounds

Posted: Fri Mar 04, 2011 2:15 pm
by Q2
Looking good! But how did you achieve it?

Cheers

Q!

Re: Transparent materials on white backgrounds

Posted: Fri Mar 04, 2011 5:28 pm
by Mihai
Looks great! We are waiting for the tutorial :)

Re: Transparent materials on white backgrounds

Posted: Fri Mar 04, 2011 6:38 pm
by RobMitchell
Thanks! Details about the setup coming soon. Could maybe even adapt it (or certain parts) into a tip of the day entry.

Re: Transparent materials on white backgrounds

Posted: Fri Mar 04, 2011 11:31 pm
by Half Life
That would be really cool! :D

Best,
Jason.

Re: Transparent materials on white backgrounds

Posted: Wed Sep 14, 2011 10:58 pm
by zdeno
and...?

Re: Transparent materials on white backgrounds

Posted: Mon Nov 25, 2013 12:05 am
by feynman
and...?

; )