Rendering a Clear Insert in a Clear Caddy

Lately I have a chance to work on a rendering like this carrying caddy for a skincare gift set shown below and I have learned some tricks in rendering. I would like to record the tricks here for future reference.

 

I used Photoview 360 in Solidworks 2014 to make this rendering image. As seen in the image, there are 3 products in the caddy, 2 skincare bottles and 1 spray mist, which are held by a clear vacuum-formed insert on the bottom of the caddy.

The most challenging part of the rendering task is to render the clear vacuum-formed insert through the tinted pink caddy. As I thought in the beginning that the light from different light sources in the scene - ambient light, directional lights, environmental light - will travel through the caddy and the vacuum-formed insert to make the insert looks clear. However, it turns out the caddy stays tinted pink but the insert appears to be dark gray. I eventually achieved the effect as shown in the above image by tweaking Photoview 360's material settings after several attempts. Here are some settings I used that work:

I. For the caddy's illumination under Appearances tab:

1. I chose clear polycarbonate as the material for both caddy and the clear insert. I originally chose glass for the caddy, and it did not work.
2. The index of refraction is 0.90. Set to 1.0 will simulate light travel through vacuum, and it did not work in my case. The setting above 1.0 will also make the insert very dark.
3. The transparent amount of the caddy is 0.80

II. For the vacuum formed insert's illumination under Appearances tab, I need to make the insert an luminous object, so it can emit light through the tinted pink caddy. Rather than relying on the reflective light that may bounce off the white skincare bottle through the insert and caddy to let a viewer like you and me to perceive the insert as a clear object, I have to add the illumination to the insert. The reason at doing this is that once the light travels from outside through the caddy, it is weakened and hardly can bounce back out of the caddy. So I must reinforce the intensity of the light around the insert by adding illumination to the insert. Here are my setting for the vacuum-formed insert:

1. I still used clear polycarbonate as the material
2. Luminous intensity is increased from 0 to 0.080 w/srm^2
3. The index of refraction increased from 1.0 to 1.33. 1.33 is approximately the distortion caused by light traveling through water, assuming the surfaces have some transparency.
4. Transparent amount is set to 1.00, which is equal to completely transparent.

In the above image, it shows how transparent the vacuum-formed insert becomes through the tinted pink caddy.

5-sided Surface challenge in Rhino 3D

Rhino is a NURBS modeling program, so ideally every surface created in Rhino should has 4 sides with isocurves running on it. However while making 3D models in Rhino, sometimes I came across with some details that require 5-sided surfaces. Then the question becomes how do you create a 5-sided surface?

I googled a bit by key words "5 sided surface rhino" and here is one comes out on top of search result: http://v5.rhino3d.com/forum/topics/surface-challenge. It is a Q & A thread started by Justin from Australia in Rhino 5 forum.

I share the same reaction with Justin about the quality of patched surface if I use Patch command to create a 5-sided surface. I resonate with his thoughts such as "Network curves doesn't work as there is 5 sides", "Patch doesn't make the edges tangent .. and when you zoom in they are not connecting"

John brock from Robert McNeel & Associates offered his 2 solutions, which I think make sense:

"The first is to extend curves so you can make a 4-sided surface, then Trim away one corner to make the 5th edge. Your model suggests the boundary curve could be the Trimmed edge, suggesting the two surface edges be the edges to extend."

"The second is to create an interior curve that goes from one corner across to another edge. Then you would be modeling two surfaces instead of one to fill the 5-sided hole."

Another method is to buy Autodesk Shape Modeling Plug-In for Rhino. This is a program that allows real-time creating and modifying Class A surfaces. Class-A surfaces are used extensively in exterior design of a car.

And Michael G. provided a file with surfaces modeled in Autodesk Shape Modeling, and I opened it to review. As you can see the image below I cropped from the file, the yellow surfaces in the foreground were created in ASM versus red one created in Solidworks.

I added zebra strips to the 2 group of surfaces and found that the surfaces qualities are very close. I am just wondering if all I need to model in Rhino are generally for products apart from automobiles. Do I need to spend $1,325 to buy the plug-in?