Infinite Slabs – The Bryce-killers
You have a fairly decent computer, with a 3GHz CPU and you have plenty of RAM – 2Gb, and you would like a plane of fluffy looking clouds in a Bryce scene, but you don’t want the two dimensional stuff that Bryce tends to produce ad nauseum. Solution – according to the Bryce manual is an infinite slab. Essentially an infinite slab is a plane object that has depth. An Infinite Slab can affect objects within it. Anything you place within the slab’s depth will be affected by the slab’s volume color.
Infinite Slabs are usually used to create water but are also suggested for creating 3D clouds, but when you make use of volumetrics in an infinite slab it will kill Bryce. A render that took a couple of minutes without the slab will now take hours and you will suffer the "hospital waiting room blues".
You lovely powerful computer doesn’t amount to much and tweaking materials and lighting to get the look you want will be virtually impossible as you will have to wait hours before you can see if your minor tweak has the desired effect.
I rediscovered a method I used for my "Ocean Gypsy" image, using stacked cloud planes to give the impression of 3D clouds, and have refined it a little bit more. It will certainly cut down on your render time and as you will see is quite acceptable visually.
To compare the speed differences I created a scene Bryce and applied the "Bryce Shortcut #2" under the Daytime library. 
I then created an infinite slab. (by holding down the left mouse button when selecting the Cloud plane creation gadget and selecting the "Volume" option.)
I applied a volumetric preset I had in my library called "Cloud Puffy Frac Stone", which I thought would give me a good puffy cloud.
A quick glance at the Material settings showed me that this was not "Bryce-killer" as the quality settings in most cases were not set too high.
Back to the main Bryce Editor window told me a different story. The nano-Preview rendered very slowly and I could see already that I was in for a long wait. So I hit the Render button and went to bed!
The following morning the following results told their own story – a 4 hour 45 minute render!
Back to the drawing board! This time I created the same scene with the same sky preset and selected a infinite cloud plane this time. 
I chose the "Cotton Ball Storm" Clouds-Surface Preset in the Atmospherics library of Bryce 6.1. It seemed a bit dark and flat so I tweaked the material settings in the Material editor raising the Ambient and Specular settings:
Still nothing spectacular…yet…but now comes the fun part.
Selecting the cloud plane I pressed Shift-Alt-D (Multi-Replicate) and set the requester to 10 copies offset on the Y axis by 0.2 Bryce units.
Immediately the nano-Preview updated a lot faster and the results looked good, but the proof of the pudding is in the eating…so I pressed the Render button.
As you can see the render is a lot quicker. 3 minutes compared to over 4 hours. The results are similar and with a little bit of tweaking in the Material Editor, very similar results can be obtained at a fraction of the rendering time!
Keep on Brycin’
On the Internet, I am a reclusive hobbit called Hamfast, who likes potatoes, all green growing things and playing with Bryce, Hexagon and who has a consuming passion for JRR Tolkien. In reality I am a retired medical illustrator who has drifted into the dubious job of manager/network guru/computer security advisor and general IT "expert" of the Faulty of Health Sciences for a local university. I am reclusive in nature – like my Internet alter-ego, and prefer spending time in my garden, with my wife and our only child, Christopher, who is almost 11 years old. Playing with computers is a hobby, as is my artwork, but that is all laid out in detail on my website on
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