Silicone ball not rendering well

Started by rhinokey32, July 28, 2019, 01:03:47 AM

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rhinokey32

Hi everyone,

I am new to this forum.  I am trying to render a transparent ball with a light inside it but I am not getting good results.  The material I am using is the standard Silicone Rubber White and for the light I am using an area light with around 50 lumens.  The first image is the one that is not the desired one which displays the grainy look of the light inside the ball.  I get excellent results when I reduce the transparency distance of the silicone material but unfortunately this darkens the silicone and makes it less transparent which is not what I want. This is shown in the second image.  The problem is amplified when I want to animate the ball as each frame disperses light differently and thus it looks like disorganized light inside the ball.  I am allowing for long render times but still the results are not good.

My computer doesn't have high specs of i5-4460 3.2 Ghz, 8 GB memory, 64-bit Windows 10.

I hope you can help.

Thank you.

INNEO_MWo

Hello and welcome in this forum.


The material you chose is a heavy one, 'cause the material type is translucent. This type use subsurface scattering.


What's the setup for such scene needs (IMHO):
- a unit system and real life scale
- a plane or a sphere as base geometry for the area light (which is also the heaviest light type)
- try to build the material with these parameters
• type advanced
• diffuse color (a grey to between 0% to 50% white)
• direct transmission color nearly white
• transmission roughness around .2 or more to scatter the light from the inner area light
• specular color to your likings (I guess 50% or more)
• keep fresnel active
- settings for lighting:
• global illumination active
• toggle of the caustics
• you shouldn't need indirect bounces
• ray bounces around 16 or 24


Now let the view port res up the scene and look to the samples count in the heads-up display.
(for questions to details of these points, just ask or look into the manual. The different materials are described well)


Good look!


Hope that helps.
Cheers
Marco


PS: description in short form - typed on a mobile)

rhinokey32

Hi Marco,

Thanks for the information. I tried these settings but it didn't give a transparent material. I will look closely at the manual to see how to create it.

Can you tell me what you mean by "a unit system and real life scale". I am using a small LED that is 5.6 mm X 3.0 mm. I am using now a plane for the light source. Is this reasonable with the area light?

Thank you.

Hanna

INNEO_MWo

Here we go. Attached you'll find a KeyShot 7 scene. The "silicone ball" (diameter of 6 mm) has a multi material with 4 different versions in different material types. All these type may solve your problem. Just choose the one that comes near to your liking and tweak the last parameters.

With "unit system" and "real world scale" I meant, that all parts should have the real size like a physical object. Then light power can be calculated correct.


Hope that helps

Cheers
Marco

rhinokey32

Thanks so much Marco for these great options.  I think the advanced material is working best but I am tweaking it for my application.

Thanks again.

INNEO_MWo

yeah - fine.


I'm happy to see your results here if you're ready and allowed to post?!


Cheers
Marco

rhinokey32

Marco,

Unfortunately I am unable to share the project here, otherwise I would have been happy to do so.

A quick question about the original silicone material that comes standard with Keyshot, do you think that with enough computer power and time I would have seen the same results as I am seeing with the material that you have provided me?  I am asking because the original silicone material still gives better results when the lights are off, as the new material is slightly cloudy.  I am using a slow computer with only 4 cores that are run by an i5 3.2 Ghz chip.

Thank you.

Hanna

INNEO_MWo

#7
Helo Hanna.

Yes, with enough time (less on a fast computer and more with a few CPU's) a translucent material brings great results for silicone.
Do you ever tried to look into the KeyShot cloud library? -> search terms "silicone" or "milky" or "translucent"

The advanced material works quiet faster, because it doesn't calculate the subsurface scattering.

Additional I can give you some resources with examples:
Dries Vervoort came up with a great webinar. In the scenes of the download section (https://www.keyshot.com/resources/downloads/scenes/) you'll find "engine housing" (with the links to the webinar recording, the ksp and the presentation)


Maybe the webinar for translucent materials will help to tweak your scene:


And the webinar for transparent materials shows some solutions:


Perhaps you can exchange the project geometry with a simple (dummy) part and keep the material of the silicone and light source, to publish your solution?!


Hope that helps

Cheers
Marco

rhinokey32

Marco,

Good to know that with enough CPUs I can get good results.  I thought it never renders to a good result. I don't think I will do it for this project (because I created an animation that was able to bypass the long rendering time) but for future projects I will know that translucent materials can be rendered nicely.  If for instance I send the job to a render farm (which I am reluctant to do because I am concerned about the privacy of my project) how would I know before sending them the job how long it would take to get good results for the translucent material?  How would I "measure" the price, if you will?

The ball was the simplification.  It is actually another shape but I did the ball as a dummy to simulate the project I am working on.  Maybe I will be able to use the same materials and render them to show you the results I was talking about.  If I am able to, and I have the time, I will try to create a better representation of what I am working on.  I promise that I will try to do it to show you how it looks like.

Btw, I saw that you work at INNEO, can you tell us a little about it? Do you have a render farm? What kind of services do you provide?

Thanks.

Hanna

TGS808

Quote from: rhinokey32 on July 30, 2019, 12:38:31 PM
how would I know before sending them the job how long it would take to get good results for the translucent material?  How would I "measure" the price, if you will?

Use the region render tool to isolate a smaller part of your translucent object so that it will res up faster. Use the heads up display (H key) to see how many samples it takes to get your material looking good. Once it looks good, you'll know the amount of samples that you'll want to use for the entire image/animation.

rhinokey32

Tgs,
Rendering a small region sounds like a good idea. I will try that and get a sample size then see how long it takes my computer and then ask the farm how long it would take them.

Thank you

mattjgerard

Quote from: TGS808 on July 30, 2019, 02:20:52 PM
Use the region render tool to isolate a smaller part of your translucent object so that it will res up faster. Use the heads up display (H key) to see how many samples it takes to get your material looking good. Once it looks good, you'll know the amount of samples that you'll want to use for the entire image/animation.

This should be a sticky note in a "Best Practices" thread.