Strugging to find the most rendering efficient way to make clear a large transparent wall, comprised of clear tubes?

[Randal]

Hi,
I am working on a project with a material called Panelite Acoustic for use as interior walls. Below is an image of the actual material, and a rendering attempt with gray wall in BG. It works good enough at this scale (19cm x 32cm) but the tubes are 1 cm in dia. and i need to make a wall 5m x 14m. The rendering is made with a single component repeated. The component is comprised of a transparent tube with one face, the front and back of the tube are gray rings.The components are within a plastic solid. (i dont need to represent the perforations in the face of the material.) I have tried other ways to make this work, using Vray Proxies, a small section of a perforated material as a component repeated, but its still a huge amount of geometry ,and transparency maps won't produce the directional transparency you see in the last image of the real material. An thoughts would be really appreciated!
Thanks!
Rand

[Martinch]

I'm familiar with Panelite. I experimented with something that approximates it. Not perfect, and not a particularly fast render but see if this works for you. I didn't create the front or back Panelite surfaces, only the core.

• I made four tube cells in their staggered arrangement and turned them into a component. The tubes are not groups, they are merged geometry. Each tube wall has 12 segments.
• I used the Skatter plugin with a grid distribution to create the core cells as render instances. The overall file size is 223 KB for a 60cm square of Panelite core.
• In VRay I made a simple material to fake those directional reflections-
  • Top layer is emissive, the color channel uses a gradient with a bunch of black and white knots to create irregular stripes. The white stripes are skinny which fake the specular streaks. The black stripes disappear since they don't emit. Intensity is 1,Transparency is at full.
  • Bottom layer is a generic Vray material. Diffuse is white, No reflection, No refraction. Opacity is 0.5.
  • Even without refraction and reflection, it still takes a long time to render. I think it's because of the transparency... A long time.
• I applied the material to the merged geometry inside the tube component, not to the component itself. And I set UV cubic mapping to fit the object.

A down side to this method is that you won't pick up specular highlights from your environment, but you could also change the colors in the gradient knots to mimic the lighting or background. Is this the most rendering-efficient way? Jury's out on that score. It's a complicated product. I thought about whether using alphas and displacement might achieve a faster result but I haven't tried that process.

[Randal]

That's a nice solution. I bet this this would be faster than what i have been doing.
As you mentioned, there are multiple ways to solving this problem.
I played with a mesh clipper too and this works well on a smaller scale, however my guess it would be too memory intense for the scale that i need.

I had continued with using a single tube 10mm x 17mm tube with a fascia for the front and back, using simple glass material for cylinder and tinted glass for the fascias.(159 KB), made that into a Sketchup component, and then created an array of 10,000 components (2700 KB), This renders fine with a simple light source.

I converted the array into a vray proxy. Sketchup file size drops to 368 KB but external vraymesh file is 34,450 KB. But still renders quickly. The size needed for the wall is 14m W x 4.25m H, so 70 proxies. With 70 proxies, the file size is now 380KB, the external vray mesh is the same at 34,450 KB.
The render time now jumps significantly.

What i wonder is, ether using your process or mine to produce the tube, what is the most efficient point when employing the sketchup components and vray proxies? Is it better to have a lot of sketchup components and fewer vray proxies? Or build the entire wall with sketchup components, and one single vray proxy. The vray proxies make navigating the sketchup file easier as its doesn't need to draw all those lines, but that's different than rendering time. I don't know enough about the way vray rendering engine works, and could spend days experimenting. I would love to have a better understanding of how this works.

I am sure there must be a clever way that fakes the look of this without all the geometry, using some advanced multi material, but I'm not sure how that would look and still pick up the color and lighting on the other side of the panelite.
Any other thoughts would be appreciated.
Thanks!