still could not find a good diamond material like the photo

ramizramo · January 08, 2018, 01:17:39 AM

Hi Guys, I am tyring to create diaomond material like the photo but I could not, I really like matrix stones material but I could not create like that. Can you help me for this? If you have material for haveing this quality I will thankful for that.

I am also added file if you can do something for having this quality, that will be perfect.

Ramo

Frody · January 08, 2018, 06:23:01 AM

Hello ramizramo!
This is an old problem
Once I also asked myself a similar question.
At my request, the developer a lot improved the old diamond material
https://www.keyshot.com/forum/index.php?topic=10396.msg49599#msg49599
But still this material is not brought to the proper level.
I was just tired and did not at that time insist on further improvements in the material.
I tried to make a diamond like the picture you showed.
But I can not.
On your photo there is only pure blue blue black and green color.
All of them are clean and not mixed.
On my render, the colors look dirty. It is brown, dark yellow.
If you make a diamond separately and use HDR with blue and green, it can look like a foto. But then the metals will also be blue.
Sorry friend on me it seems that in Keyshot it will not be possible to do it. ((
A little frustrating that the Keyshot is positioned as a renderer for jewelry is why it is so difficult to make a beautiful diamond.

I attached a file with a ring.
Maybe I do not know how.
But someone will get it and he will tell us how to do it.

Frody · January 08, 2018, 09:06:57 AM

The problem of the Gem material is the wrong color reproduction with a low number of ABBE. If the HDR is black and white color then is a spontaneous mixing of colors among themselves and a dirty color is obtained. As a result of this mixing, brown dirty yellow and reddish shades begin to predominate

KeyShot · January 08, 2018, 09:48:18 AM

You can see color mixing on photographs of actual diamonds as well. E.g.

http://www.epicmind.com/blog/2011/01/photographing-a-diamond-on-black

The lighting is key and camera angle is important to get clean dispersion. I recommend starting out with a simpler shape and no metallic parts to work on the lighting and and camera angle of the actual diamond.

ramizramo · January 08, 2018, 09:55:23 AM

this answer was not helpful enough
there is no one who can get the ksp file we sent as photographed here please please

Frody · January 08, 2018, 10:37:19 AM

@KeyShot greetings to you!
How to achieve that when using a black-and-white HDR map, in the diamond was dominated by shades of blue (without dirty brown dirty yellow and dirty red) ?

Frody · January 08, 2018, 12:16:29 PM

A long time passed.
I did not follow it and could not respond in time.
Now it is closed and I can not write there.
I do not know whether I rightly publish my belated answer here ..
I think my answer will be relevant here.
If not, then moderator, please correct me.

https://www.keyshot.com/forum/index.php?topic=10396.msg52340#msg52340

Quote@Frody

Would it be possible to share your KeyShot renderings?
Can you share the model you used to render in Bunkspeed?

It would be great if you could help us match your results as close as possible.

I did some quick test rendering in KeyShot 6.
What do you think?

Dries

Hi Dries!
The material has become much better than it was in the previous versions.
But still needs to be finalized

All the same, there is a certain amount of turbidity and lack of detail.
At a low ABBE The colors mix with each other incorrectly. They do not correspond to the laws of physics.
Herein lies the main problem of not realism.

Below I am attaching two projects of the same product in different programs (Bunkspeed is now SOLIDWORKS Visualize) project in this program.
The material is configured the same. To see the problem at a low level, I lowered the number of ABBE to 5. The same HDR.

In the KS renderer, you can see that the blending of colors does not match the color spectrum. Hence all the problems follow. For example, between blue and red flowers there is dark purple (very dark almost black).
This does not happen in reality. This error is always present.
In SV there is no such problem. Colors are mixed correctly according to the color spectrum.
At any ABBE, the diamond always looks right. For any ABBE diamod always is clean. No dirty yellow and dirty brown.

Frody · January 08, 2018, 12:43:23 PM

BS old

KeyShot · January 08, 2018, 04:36:33 PM

We do of course use the correct spectrum for dispersion. I am not sure where you get your wrong spectrum idea from? I can see that you use multiple parallel linear lights in your environment, so overlapping spectra is to be expected.

Frody · January 08, 2018, 07:42:31 PM

Maybe not a spectrum. Maybe it's something else.
How should I know? Just it looks awful and that's it.
I dont know what can influence the appearance for dirty colored.
But something influences.
Do not need be a great aesthete to understand. it's obvious.

I made two renders with both programs.
The same settings. Specially Low number ABBE.
The same map of the surrounding world.
I am attaching both projects.

Frody · January 08, 2018, 08:05:59 PM

Here are photos of real diamonds. This is not a render.
It becomes obvious that SW render is quite capable of photorealistic. All the same colors and the same gamma.
Over the years, I've been trying to convince the Keyshot team of this...

ramizramo · January 08, 2018, 09:33:39 PM

I believe that this problem can only be resolved in the following way
there is no one who can render the keyshot files we uploaded to the clipboard as pure and clear diamonds?
or we are pure and clean diamonds reder how do we say

chicongds · January 09, 2018, 02:45:15 AM

This is render by vray in Gemvision matrix. It's not same keyshot
you can try do it by matrix software but can't render same in keyshot.

Thank you.

ramizramo · January 09, 2018, 03:39:57 AM

I think KeyShot is a better render program, but KeyShot programmers have to help us

KeyShot · January 09, 2018, 07:20:52 AM

Frody,

Thank you for your feedback.

I took a look at your file, and I found a few issues that I think will help improve your rendering.

1) The environment map contains fairly large light sources, including one which has a brownish color?
-> if you make the light sources (pins) significantly smaller and make them white you will see a cleaner spectrum

2) The background color in the scene is gray. This color is reflected in the diamond, which gives it a grayish tint.
-> make the background black if you want to emphasize the dispersion

3) The diamond is rather large (10-11mm). It is perfectly white (no absorption) and with 24 bounces you will see a lot of overlapping spectra.
-> To go for higher realism you may want to add some absorption (use the transmission color). You could for example lower the red and green a bit to get more bluish transmission if that is what you are looking for. The reason the default diamond in KeyShot is white is, so that it will easily work with geometry of varying sizes. We may customize this further to support for example yellow and pink diamonds.

These are just a few starting points. If you would like to further analyze dispersion in KeyShot then I would recommend to simplify the scene to a prism and a small light. For a prism the spectral output can be computed analytically and this can be used to verify the correctness of a given rendering.

KeyShot does use the actual physics to compute the dispersion. It uses a quadratic approximation of the variation in the index of refraction to compute the dispersion of light. This is the standard method for dispersion in the physics literature. The method is fully spectral (not just rgb, which would limit the colors to pure red, green and blue). The mapping from the spectrum to the monitor uses srgb, which does put some constraints on the available gamut, but I do not think this is an issue here.