Acrylic plastic

This look fantastic. I will give a try with the scene to see how it behaves when the wood structure is there.
Thank you

Hi ! I tried in my scene. It is behaving strange:

If you check the wood is “cutted out” in the intersections with the acrylic.
I noticed in your proposal that now the ray depth is plugged in the multiply and the ray lenght is in the grather than. Before was the ray depth in the grater than…

I do not have much idea of what this light passes are doing so I am just pluggin them kind of randomly…
so far the option

is the best one…but not sure …if this is the way to go.

To mix the whole shader without a driven fac with transparency makes not much sence.

These Lightpath factors especially raylength and depth are highly dependent on the mesh thickness,overlaping mesh in the view ect. Similar to black parts you get without enough transparency sample settings in the render settings.IE how often the ray pass a mesh and bounce back ect.

look here ray depth and length
https://docs.blender.org/manual/en/latest/render/shader_nodes/input/light_path.html

As sayed this was a quick setup with the plane underneath.I am not sure what you expect,maybe you have a reference pic we can see.

Thanks for your fast responses and help!
I think its easier if I share the furniture with a boolean so its easier to appreciate what is happening:
boolean

There is a wooden structure surrounded by a plastic “lid” (acrylic). I am trying to achieve a render that could work to present it as far as close to reality. Due to the nature of the furniture I want to portray I need to show the light as accurate as possible. The light going through the structure and casting the grid in the floor and the acrylic are important.

Thank you so much

If you want I could send you the file privately?

ok,i can take a look then

I have send it to you! Thank you

Here a setup variation.With this setup the raydepth calc only appear if its in shadow.
This is a comprimise.If the raydepth multiy is too high then the shader gets too transparent.
Maybe there is a more elegant way to handle this.
I placed a area light in the back of the chair for better reflection.And you should play with lighting/hdr for better reflection.

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Thank you ! I will give it a try with this settings. It seems better than what I achiever by myself.
I am also trying luxcore sin I heard its really good handling these type of issues.

Thank you so much

I am testing luxcore. I am curious to see the difference between the outcome from cycles and luxcore.

I believe the fact of having caustics might help to portray the acrylic shadows in a nice way too.

As a HEAVY lux core user for my clients work where photo realism is not just expected, it is manditory, Lux Core is going to beat cycles 9/10 times but is far less versatile. Just don’t use the disney shader. It really is a train wreck. That’s not lux’s fault though. They are going along with the literature set by pixar for that shader. Trust me if you are doing stills and don’t mind a few extra minutes render time and a slight learning curve on the lighting, lux will win in terms of straight out of the engine results. I am sure you could post produce cycles to look pleanty similar if not better than Lux but I am definitely a fanboy. No shame. And I don’t fanboy easily. I have used almost every notable engine accessable to the public and a few that aren’t and I would say my short list in order is: Arnold; LuxCore; Thea; Cycles; Octane. I have maya so I have arnold and luxcore is free so those 2 come in first and second but if I still had thea, that would probably be second. For product work spectral rendering, or at least spectral lighting in the case of luxcore which is more of a spectral hybrid now, is super helpful.

Thank you so much for your insights. I am actually trying to use the disney shader to replicate a velvet carpet …mmm it seems similar to principle in cycles…I am not an advance material guy in cycles…so I can not say much. Also is my first day using luxcore…for the purpose of achieving the acrylic surface…it definitively did the job. But I will not pick a side …I can use bot :slight_smile: and I find both relevant in different cases. What are your thoughts regarding Octane. I am an industrial Designer and I am trying to find one engine to keep working in the future.

I have not tested all shortcomings the glass shader has,but to me it seems like a bug.A transparent material like common glass should the light pass trough without any hacks,at least the refractive amount of the Fresnel curve.

I love octane but likely it will very soon be C4D only so if you are not a C4D user I would be cautious with that one. It is a great engine but it can look a bit plasticy to me at times. Same problem I have with cycles. I don’t quite know what it is but the lighting in both tends to look just like a photoshop gradient. I don’t feel that same feeling of reflections of space that I get from luxcores caustics and everything that really breaks up the lighting. Of course, you can boost the bounces and that may have a positive impact but for me personally bounces to bounces lux looks better to me. And you really should use both. I do. I would say 50% of my work is done in cycles, 10% in arnold, and 40% done in lux. Lux is just AWESOME for lighting. It feels very atmospheric. You get a sense that there is an environment outside the shot frame, provided you have good lighting or things off frame to reflect light, that I just don’t feel in cycles and thats why I really like lux for product work. I do product visualization for internal use for a company that fabricates composite (well just say) parts so when we are working with a client I sorta subcontract to that client and I need to make something very photo real or else they may not be interested. I need the client to feel like it is already shipped and in the mail to them, not just an idea… lux does it for me and I spend 5 minutes in PS. Cycles is mostly for complex scene work and I may spend as much as and hour getting a shot to look right with cycles so it looks consistent with the quality I get with lux. Octane is sorta the same story. It looks REAAAAAL good and I like it, and its FAST, but it also comes with a lot of the same hickups as cycles where it just feels a little too perfect all the time.

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I might be late to the party here, but I’ve used a simple glass/glossy mix for acrylic/lexan/plexiglass, like this:

plex

if you want less refraction, you can turn the IOR of the Glass node towards 1, and if you want more ‘clear’ plastic, you can decrease the roughness of the glossy node.

I don’t know if it’ll be accurate enough for you, but it’s simple enough of a node group to give it a try.

Your setup still has no transparent shadows.

No, it’s not a bug. You just need a lot of samples with both caustics enabled. Glass is opaque to shadows, and should be, it’s all handled by the caustics calculations. That said, glass shader should have a checkbox for simplified shadows. Fresnel node should have switches for single sided and roughness modulated.

Yeah you can do hacks to vaguely simulate glass shadows using single sided inverted fresnel on the shadow rays with no caustics, but it has serious realism limitations.

I’m not talking about trillions of samples needed to resolve caustic patterns for path tracer, but big enough for light transport significant enough to be clearly visible.

Hi CarlG. Thanks for joining back. Do you have a setup to propose for the acrylic material ? something different from what I am attempting and people are kindly proposing?

Well, you have to check “Transparent Shadows” in the Material Settings:

shadows

Transparent shadows is enabled.

This is a tryout with the proposed node. If you compared to the image to:


Thank you