Everything related to Maxwell Render and General Stuff that doesn't fit in other categories
By ki_cz
Hi all,

I'm sure this is more simple than I'm making it, but I'm really struggling with making a material similar to the attachment. I'm under the assumption that the 'edges' are the same material as the sides, but maybe that's incorrect?


Currently anything I seem to try ends up looking too much like glass rather than this almost glass/plastic type of material.

Thanks for any help!
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By Nasok
Hey ya!
It does look like glass .. or acrylic if you want.
I would do that by first focusing on primary features and then on secondary.
Quality of the image is pretty low so it is hard to say what is happening on the side of those panels, but here are few observations:

- it is Red  🤓
- it is transparent
- it has very small attenuation distance (obviously)
- it has a strong directional light source positioned in a way to have this coloured shadow possible

So I would start with making it a simple transparent materials with, say, around Nd 1.3 and a pretty bright red colour for attenuation. As for the attenuation distance - uh - it all depends on a real size of your geometry - but probably something about 5-10 cm.

Now the more I look at it the more I think that is was made in something like v-ray or Arnold (or poorly photoshopped) where you can give "glass objects" transparency with colour without using attenuation distance. And if you're concerned that side of those panels doesn't look like glass (you can't see much of the refractions there) - it might be due to the nature of the render engine - but if such look is what you're up to - then I would the following

- just add a little bump on sides to diffuse those areas and make it more look like a opaque colour rather than proper side of a thick acrylic panel

But judging by the pretty strange looking coloured shadow - feels like that those sides are transparent in fact as they do have a variation in brightness - maybe it;'s just the quality of the image is low so compression makes it look like a solid colour.

By ki_cz
Hey thanks for the help so far.

I think the image is actually a photo, not a render, I'm just using it for inspiration. It's kind of similar to Larry Bell's Pacific Red:

https://i.pinimg.com/originals/95/4a/c6 ... 3bbadf.jpg

My current problem (and problem that I've had for a while), is that while I can get transparent glass to work without a problem when looking "through" it, problems start to happen when I need light to shine through it, in the case of colored glass it seems to consistently cast a black shadow. I'm attaching images below, this was at SL 15.7, the glass pane is 3m x 3m x 1cm.



Thanks again for any help.
By Andreas Hopf
Tinted polycarbonate plastic works only in a Viewport or normal render, not in FIRE, I think. First example with Dispersion on in Global Properties (slows down rendering somewhat, for no use with that scene here) and some Abbe. Second example without Dispersion/Abbe (so no 2nd level transparent shadows), but a tad o' scattering to get that edge light collection effect (slows down rendering considerably). One would probably have to combine Dispersion/Abbe and scattering to replicate that type of PC as shown in the sample image, and a faster CPU, lol.


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By Nasok
Andreas is right - FIRE preview doesn't really show transparent shadows much .. not sure why :)

But if you'll do a viewport rendering - it does - feels like it is even simpler than it looks.
Check out the quick screengrab
Setup is super simple - plane (wall) and 6 "glass panels" 1 by 1 meter with 4 cm thickness.
As you can see the glass material is super simple - there was even no need to convert it to a layered one. I've just, make it red, reduced IOR, and increased Spec tint - as it feels like that glass in your original reference is ... unnaturally.. red - which looks a bit fake to me, but you know - ref is a ref.

There you go - I'm sure you can control the overall effect with the glass panel's thickness, distance from each other, and attenuation distance ... no even need to mess with scattering, dispersion, or even R2 :)

I believe it's just the FIRE preview that confused you :) 😜

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By ki_cz
Hi all,

Thanks for all the help and examples so far, I actually tracked down the issue and it thankfully wasn't totally due to my overly basic understanding of materials.

When using an image based environment (HDRI) in the 3ds Max plugin, the light doesn't pass through the glass properly, but when using Maxwell sky/sun, it works fine. Has anybody encountered this issue before?

I'm still on Maxwell 4 by the way, so maybe I should ask in the legacy boards?
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By Nasok
Hmm .. never had a similar impression - most likely your HDR image doesn't have enough intensity in the "sun area" and probably just capped at some value - try placing a light source there.

Usually HDR images (for IBL) capped at 4 steps, sometimes at 8 steps - might not be enough - depends on quality of the image :)

Hi ki_cz,

this is my attempt with another engine, but maxwell will do this (with infinite time). It is a known problem with refracted caustic (from the sun or any too directional light) seen through dielectrics (real glass). You can see caustic (colored light in the shadow) directly, but not through the glass. Know workaround is to use AGS, but this is without refraction.
And Artem - Fire doesn`t show caustic (transparent shadow that You point) - it is probably computationally difficult for fast preview (please correct me if I am wrong).
If You want to see that caustic with real glass and part of it through another glass, You should change the sun radius to 4 or 8. The bigger the Sun radius the sooner caustic will show. With radius 1 caustic seen through glass will appear in not prefect quality around SL45 (approx, not exact). With Sun radius 8, it will start to be acceptable around SL35 (approx, not exact). But with a bigger Sun radius, shadows will be softer. The sun is about 0,5 degree, so is the shadow falloff on the shadow edge. With sun radius 8x = 4 degrees Sun = 4-degree shadow falloff on the shadow edge. Hope it helps somehow :-).

By ki_cz
Hi all,

Thanks again for all the comments and suggestions. Seriously, the root of the problem came down to the fact that using IBL, the light would never pass through the panes. In the end I'm using Maxwell Sky for illumination, then IBL for reflections, etc. It seems to result in what I wanted to achieve.

Still I'm surprised that the HDRI images from here:

https://3dcollective.es/en/producto/hdr ... k-pro-eng/

Weren't high quality enough to be honest, but fortunately this is just for a personal project and nothing so important.

Thanks all.
By ki_cz
Oh wow - those are some serious gourmet sh%t
Haha, I got them through work and have just stuck with them for a while I guess.
these guys do pretty decent HDRI - https://hdrihaven.com - and they all 100% free.
This is a great resource, thank you! The indoor ones are especially useful, wow.

Regardless, I'm still having the same issue. The render on the left (SL10) is from this HDR image: https://hdrihaven.com/hdri/?c=outdoor&h ... n_field_02

Image on the right is with Maxwell Sky (SL8) with all other settings being the same.


Is this something that has been brought up before?
By ki_cz
Still wondering if anybody has any solution to what I've shown above? There's many instances where I'd much rather use image based lighting rather than set up lights manually, but if it can't be used with transparency it seems a bit pointless sometimes.
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By Nasok
Interesting, and you're right - I couldn't make it work either.

for glass material I've used a transparent glass preset with a transmittance distance of about 50 cm so it is pretty clear.

Here's the Physical Sky (Left - view port rendering | right - FIRE)

And here's the HDRI (Left - view port rendering | right - FIRE)

I even increased HDRI intensity to somewhat match the brightness of the "sun", so I even had this HDRI with intensity 20 - still, this is the best result I've got.
It feels like that it just doesn't allow a transparent shadow or in my case shadow inside a shadow.

Now I also feel a bit .. hmm confused .. guess I'm also doing something wrong, maybe devs can help us with that?
Luis? Fernando? - you guys wanna give us a hint? :P


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