Clear Objects & Rendering Time

I use Rhino and Flamingo and I am aware that Flamingo is a slow rendering package. Where it really slows down is with clear objects. Unfortunately for me, I am working on a product that uses hundreds of test tubes, several 96-well microtiter plates and it seems endless tubing (it needs to be clear to see air bubbles). Some of the housing designs have a fair amount of plexiglas windows. The designs that don’t have this “clarity” (I love a good pun) render much faster. I would say a high res (3000x2000) can take up to additional 60 minutes for an object with a lot of glass.

Is this a problem only to Flaming or do other rendering packages slow down for clear materials? If it is common to all packages, are there any of the parameters (transparency, refraction, reflectivity) that can be tweaked to speed things up while keeping the transparent look? If it isn’t common to all packages, which don’t slow down? Thanks for any help.

Clear materials require raytracing to emulate real world phenomena like reflections and refractions.

Making raytracing calculations will always add to rendering times in whatever renderer you chose to use, the only difference being how efficient the raytracer is in the particular program you use. If you want to speed up raytracing calculations, reduce the number of bounces (also called ray depth). This will also lessen the realism of the image considerably.

Max/Viz far outpeform Flamingo when it comes to raytracing and GI/radiosity.

If it’s only an extra hour, count yourself lucky. When you start to crank up the raytrace settings to get hyper-realistic glass, each notch will probably multiply your rendering time rather than adding to it :slight_smile:

I use Mental Ray, which I understand is somewhere in the middle time-wise. And yes, it does take hours and hours to render transparent things. The worst I had was a series of glass objects, each with an iridescent clear-coat on the outside, filled with physically accurate (caustics and all that hooah) liquids, and a separate blobby layer outside that to simulate water droplets. Add some HDRI rendering and global illumination…days to render a high-res image. Ugh.