Rama is an interior model of the Rama spacecraft from the Arthur C. Clarke (& Gentry Lee) stories in that series.
Wherever practical, the design paramters were taken from the books. However, the books were remarkably silent about most details. This document will summarize what is known and what implementation techniques were used.
The books -- especially the first one, Rendevous With Rama -- talk of the spectacle of the inside. The model is accurate enough to actually recreate some of this spectacle.
Keep in mind that this spacecraft is many kilometers across. Small details -- say, anything under 100 m -- simply don't show up at those distances.
The outside dimensions were a cylinder 50 km long with a diameter of 20 km. At one end (the "North" end), there are three small cylinders (about 10 m diameter and a few meters high) near the central axis. These are used to obtain access to the interior.
The outside dimensions of the model are nominally correct. As the outside is very boring, I opted to keep the model simple by not bothing with creating an outside skin or any outside detail at all. There is a bulge in the model that is not in the actual spacecraft: see the notes under the Cylindrical Sea.
Lighting was provided by six "strip lights" with three in each hemisphere.
The presence of the lights is reflected in the model. Actual light is provided by two spherical light sources placed in the center of each hemisphere. A few of the shadows -- especially around the South Polar spires -- are wrong, but there is otherwise little difference between the model light sources and the actual ones, which I was unable to re-create within Bryce.
This is a huge disk 20 km across. You enter at the center of the disk. Three ladders/staircases stretch out to the Northern Hemisphere plains. Along the way, there are five "rest" ledges about 10 meters wide. The first one is 500 m from the center. The ladder/staircases start as ladders and slowly curve outward and become fairly flat at plain level.
The books talk about using sledges to send supplies from the access core to the plains. They don't mention how they dealt with getting the sledges past the ledges.
The books mention several times how the "Y" of the stairway is clearly visible from all over Rama.
The books are silent on things like color of the cap itself and the stairway. So I assumed a dull gray and black, respectively. I assumed that the cap was 4 km thick and, for simplicity, assumed spherical cutouts. The ledges are the correct 10 m wide, but I had to make the ladder/stairway 100 m wide to be visible across Rama. Even at that, they are not really visible due to distance and haze.
Overall, Rama is 50 km long. The Cylindrical Sea is 10 km across. This leaves 40 km for the Northern and Southern halves. I arbitrarily -- but reasonably -- assumed that the plains were 16 km each and the caps were 4 km.
This portion is somewhat irregular, mostly flat, and has six "cities" across it. Garden of Rama indicates that the shell is 200 m thick.
Dimensions are as above. The terrain is a 2D image with a 1:4 aspect ratio. I used Photoshop to blend together a variety of (copyright free) images including concrete, marble, and a false color topographical map of Venus(!). The six cites are, in fact, high resolution aerial photographs of my house in St. Paul (:-). The bump map is from a separate 2D image. The lights were created in ClarisWorks Paint.
Again, no mention of features (other than the spires) or color.
There is a central, conical spire 5 km long on the main axis (no mention of diameter at base: 1 km assumed). It is surrounded by six spires half its size (therefore 2.5 km and 0.5 km). No mention of distance away. There are "buttresses" going from the small spires to the main one. No description of details. The color of the main spire was mentioned as white.
Well, Bryce can do cones. I had to guess at the buttresses and just invent whatever looked nice. The color is white, with a strong ambient color to make them look unearthly and make up for the fact that the light source is hitting them from the wrong angle.
It's 50 m from the Northern plain to the Cylindrical Sea and 500 m back up to the Southern plain. So we have the diameter.
While the Northern plains are "wild" and "chaotic" (terms used loosely), the Southern plains are an orderly grid with each square about 500 m on a side. There's a "green belt" around the Cylindrical Sea.
Again, ClarisWorks Paint and 1024 x 256 2D image. Yes, there's a handful short of 4,000 squares, each separately flooded in ClarisWorks Paint. I tried for an "orderly chatoic" effect. The image was desaturated some in and noise added by Photoshop. Again, a separate bump map. Lights as before.
It's 10 km across and -- at most -- 150 m deep. The books talk about an "organic soup," so one might assume that it had a tinge of green. There are underwater anti-slosh baffles at regular intervals.
The first book notes the difference in height of the north and south walls and it computed a maximum accelleration of 0.02g.
Later books (Garden) mention actual accellerations of 11g. So, either the Cylindrical Sea is drained into holding tanks during maneuvers or someone needs a really big mop and bucket to clean up the mess...
Just a cylinder with water. I found a nice Bryce water texture that was just right. Only it was blue. Tough, I thought, there's too much green in here already, so I stuck with the blue. Since water is transparent, the outside sun was showing through. I added a black "tire" aound the outside to block off light.
It is an island in the Cylindrical Sea (the only one) 10 km long and 3 km wide. It is presumably centered in the sea. It is in three "lobes," each of which is in thirds (double, triple redundancy). Is is vaguely industrial / city looking, but more like a refinery than a city. It is a place that machines are happy in.
I used three terrains. Technically, the curvature should be visible. In practice, they were just on the edge of being able to ignore that effect, so I did. If they were even 20% larger, you couldn't ignore the effect. I used "spike" noise in the Bryce terrain editor to make them.
Note that the spires are way too thin to be real buildings. Again, think oil refinery towers not a downtown scene.
Last modified Tuesday, 2010-03-02T20:47:01-06:00.