Dichroic, iridescent glass material

cereal · June 07, 2017, 06:26:38 AM

Hello Keyshot Forum!

i need to render dichroic glass and i kinda dont get the results i'm looking for. Unfortunatly it's for a company so i can't share the full product.
Here are some examples how it should look.

Here are my trys.

My approach was a using a color gradiant map with rainbow colors and change the gradiant type to :view direction.
Any ideas to get better results?

Thanks in advance

DMerz III · June 07, 2017, 09:19:27 AM

Whoa, interesting material. This totally has me stumped, hopefully some of the more seasoned experts have some ideas!

Esben Oxholm · June 07, 2017, 11:42:42 AM

Not sure if it is possible to create a material that behaves like that in KeyShot.
A solution could be to do several shots and combine them in photoshop afterwards.

Best,

LayC42 · June 07, 2017, 09:04:48 PM

Hmm, that is a heavy nut! Whish I had the time to play with.
Who can crack this?

DriesV · June 08, 2017, 02:46:46 AM

I wanted to upload a KeyShot 6 material, but I can only make this work in KeyShot 7 (which is currently in beta)...

The approach is quite simple.
I used a colored Dielectric material as base and put a Metal label on it. I then applied a very fine Mesh procedural texture as opacity.

I was surprised to see it works quite well.

Of course on very tight close-ups, you can see the Mesh pattern.

Dries

DMerz III · June 08, 2017, 08:05:27 AM

Hmm, thanks Dries!

Can you explain why this node setup wouldn't work in KS6? Just curious what might have changed in KS7, all of these nodes seem available in 6, no?

Thanks in advance,

David

DriesV · June 08, 2017, 08:31:14 AM

Hi David,

It is due to a limitation in KeyShot 6, where adding a Label onto a glass material cancels out Caustics.
Here is one reason to upgrade to KeyShot 7.

Comparison images KeyShot 6 vs. KeyShot 7 are attached.

Dries

mattjgerard · June 08, 2017, 12:54:45 PM

oh dang, thats a big deal right there!

DMerz III · June 08, 2017, 01:05:12 PM

Wow, nice!

Is this the reason why I cannot see a label placed 1-sided inside of a piece of glass? (It will become visible on both sides if I turn on 2 sided with normal projection, but sometimes that's not what I want. I want the label to appear UNDER glass.

Either way, very interesting! We definitely plan on upgrading to KS7 even without knowing this feature, but thanks for explaining, Dries!

DriesV · June 09, 2017, 01:32:04 AM

Hi David,

Do you simply want to apply a Label on the back of a piece of glass, so that it shows through at the front?
That should just work.
Apply a Label on the back (Normal Projection), make sure 'Two Sided' is checked (it is by default) and finally lower the Depth of the projection, so that it is less than the thickness of the glass. I think you may have missed that last "depth" step.

See attached example.

Dries

DMerz III · June 09, 2017, 11:13:46 AM

Hey Dries,

I'll give the depth part a try, I thought I had tried this in my previous attempts, but I'll go back and retrace my steps. If I still have an issue, I'll post an example!

Thanks again,
DM

cereal · June 09, 2017, 11:52:51 AM

Thanks dries for solving the problem! Very interesting approach

I only have Keyshot 6 at work so i can't get the same results. But I'll definitely try it out with KS7 soon!
I think I'm gonna stick to Photoshop. I'm gonna try something out and show you the results later

DMerz III · June 09, 2017, 12:33:46 PM

Sorry, did not mean to highjack this thread, but I would say the caustics and label difference between 6 and 7 is still related!

Dries, here's an image to illustrate my point.

It looks like an odd composition because I cannot show the entire part.

Keyshot 6.3 Pro
I have done as you said, the label is Normal Projection on the 'backside' of this glass part. 2 Sided is on, and depth has been lowered so it appears only on the backside.
However, this label is NAVY...and it appears correctly only when caustics are turned off. When caustics turn on, the label appears black. This is fine for my purposes now, but it does confirm your original point that KS6 doesn't show labels properly with caustics ON. I couldn't figure out why I was getting black labels before, and this helped clear up that confusion, it was the caustics restriction. Glad KS7 resolves this!

Thanks again, see attached for demonstrative purposes. (1st image, caustics off, 2nd image caustics on).

DriesV · June 10, 2017, 01:12:07 AM

Hi David,

Yes , your issue is indeed related to the Caustics bug.
That being said, Labels using the Advanced material don't show the issue.
So if you really want to use Caustics with Labels on the back of glass in KeyShot 6, then that could be a solution.

Dries

DriesV · June 10, 2017, 01:28:27 AM

And just now I realized that you can use the Advanced material to mimic metal by using a high refractive index (10).
So it is possible to do dichroic glass in KeyShot 6 after all.

Scene and sample rendering are attached.

Dries