Quick scaling

Post by **Jedi Master Spock** » Tue Oct 09, 2007 12:23 am

Figured this was worth jotting down, since I put a little time into it:

The problem with any scaling of distance between two objects of known size is that we usually don't know precisely how far from the camera the nearer ones are. We can, of course, guess if we have clues. Now, examine this shot. This happens to be near the beginning of the shooting, and fortunately for us, there's a Bird of Prey close enough to the camera that the rear engine box is noticably larger in proportion to the head.

Recall these figures (see Ex Astris Scientia for detailed BoP model galleries):
Bird of Prey: 110 m long.
With wings down:
Height: 53m
Wingspan: 160m
Engine box to largest diameter of head: 88m
Engine box to head diameter: 5:6
Engine box to length: 5.4:1

Ratio of engine glow to head diameter seen in nearest BOP: 11:10.
Enlargement: 1.3
Engine box to length: 2:1
Compression: 2.7

Per the above [and a little geometry], we then know the head is 82 meters further than the box, meaning the camera is around 270 meters from the BoP.

The Jem'Hadar attack ships that we can distinguish from stars are blurs 10-12 pixels across, representing 95m objects at various angles. Assume they present a roughly 95m dimension to the camera (a reasonable assumption, given they're scaled at 95m long and slightly wider than they are long), we get 7.9 m/px for the closer attack ships. Since we can't measure tip-to-tail length of the near BOP, we'll measure its near gun (which is firing) - known to be 30% of the BoP's length, or 33m. It's also about 39 px, and at an angle that shortens it by a factor of 2.7, meaning our scale is 0.31 m/px.

This means the nearest Jem'Hadar attack ships are around 25 times as far away as the near BoP, or 6.8 km. Note, by the way, that some of the BoPs have heights of as little as 22 px, meaning they are at 2.6 m/px, or 2.3 km away from the nearest BoP.

Praeothmin · Post by **Praeothmin** » Tue Oct 09, 2007 2:13 pm

Is that another argument you have against Aratech, JMS, because I've seen him ask for help in scaling something similar on SDN...

Post by **Jedi Master Spock** » Tue Oct 09, 2007 5:28 pm

I did the scaling in anticipation of him actually getting help. Unfortunately, it appears he didn't get much help, and just guessed <1.5 km.

Praeothmin · Post by **Praeothmin** » Tue Oct 09, 2007 7:37 pm

Well, someone did point out to him that there are 2 (accpted or official) BoP types with different sizes and that he should make sure of which one he was seeing... :0