Rendering Glass and self-illuminated materials using Rhino internal renderer

Rhino Rhino for Windows
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1

Hi everyone,

I’m having a hard time with lighting and glass using Rhino 6’s internal renderer.

I’ve built a recessed light with a point light as the light source and a fully opaque piece of glass with ‘self-illumination’ checked as the lens for this recessed light. I built it this way because I want both illumination of a surface, but also the light itself appearing to glow.

My first problem is that I can’t get the light to illuminate the ceiling it is recessed in without turning up the intensity of the point light until the surface it is illuminating is totally blown out. However, when I am orbiting in rendered view, it looks exactly how I want it to, and goes back to the completely darkened ceiling when I stop orbiting.

Here’s a photo of what the scene looks like when I’m orbiting:

IMG_2994
IMG_2994866×1154 147 KB

Here’s what it looks like when I’ve stopped orbiting:

IMG_2995
IMG_2995866×1154 156 KB

And here’s what it looks like when I actually render it:

rhino renderer
rhino renderer1320×757 78.4 KB

Second, how do get the glass to behave as it should? You can see above that the surface beyond is distorted through the glass.

However, when viewed in the viewport in rendered view it appears more as I would expect. Does this have something to do with the checkboxes for Fresnel reflectivity or Alpha transparency?

rendered view
rendered view1105×904 36.9 KB

Thank you all in advance for any help you can offer. The file I’m working off of is attached here.
roof lights.3dm (2.4 MB)

2

I know it seems like an excuse, but try Rhino 7. It has a much better render engine, especially when it comes to emitter materials.

image
image1034×540 351 KB

Another addition is that lights can have linear or squared falloff. This week get you the effect of light falloff by distance you require.

There is also true frenel reflection, although that effect is subtle. In this case.

3

Thanks Scott, I’ll use 7 when I’m a little further along, as you are right, the renderer looks great. I first want to try to figure out these issues in 6, as I believe they are solvable, and will help me understand lighting and rendering a little better.

4

Hello - it’s going to be tough to get the V6 raytracer to do what you want - it does not have secondary light bounces needed to light that ceiling from below with reflected light. A large rectagular light, quite dim, on the tabletop, pointing up, may fake it well enough. For the glass to look ‘right’. it either needs to have some thickness so that the camera ray knows when it is in and when it is back out of the glass, or less accurate but simpler - set the glass material on single surface glass objects to have a IOR of 1.

-Pascal