FIXED

I am a chronically right-brained sort of person and I need a left-brainer to help me out, if you could be so kind.

Okay, I got this problem, it's a stupid problem but I'm tired and I can't figure out what I'm doing wrong.
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I've got a series of 3d models I made representing characters and spaceships. What I've done with them is size them all so that they're properly in scale with each other.

My 3d program, Cinema 4D, measures in units of "m," e.g. "this cube is 200m wide." I don't know whether it's meant to mean meters or not, but to make it easier on myself I thought I'd scale the models accordingly.



So here we have the three models. The two spaceships have been adjusted for size to fit the mannequin, so the actual scale is fine.

The problems seem to arise when I try to convert the units to miles, things start to seem off.

Small Spaceship:
370m = 1/5 miles

Big Spaceship:
38,000m = 24 miles (!!)

Now, the big spaceship is admittedly pretty big, like so (the red line indicates the length of the small ship, since it's hard to see):

But even so, 24 miles seemed high to me. So did 1/5 of a mile for the small ship, for that matter--it's not really much bigger than a real-life cruise boat. But given the size of the objects and my own shaky ability to estimate at this scale, I just kind of ignored it.

But then I tried to make an animation and things started to fall apart.


What I did was set the framerate of the animation to 24, since that's standard. Then I set the total frames of the animation to 240, because I wanted it to last 10 seconds. Then, I animated the small ship to fly the full length of the big ship over the course of those 10 seconds. And it looked pretty good!

Unfortunately I got curious and decided to try and find out how fast it was going, and here's where my troubles began. To calculate the speed I measured how far it went in a single second, based on the relevant coordinates at frames 1 and 24.



One's a negative number because it crossed over the origin during that second. So I thought, "why don't I add the two numbers together!" And I did.

3,463m + 346m = 3,809 m/s

So, I thought, it went 3,809 meters in a single second? That sounds too fast. So I went back to the converter.

3,809 m/s = 2.4 mi/s
2.4 * 3600 = 8,640 mph

8,640 miles per hour is way too fast. I've played through the animation several times and I'm sure that's not possible. I've seen jet fighters fly faster than my imaginary spaceship is going (based on my visual estimate, anyway) and I know those jets were traveling well under mach 1 (770 miles per hour).

So, obviously, the numbers don't add up. And I redid all the math while making this thread and got the same results, so it can't have been a typo somewhere. What am I doing wrong?

Perspective

I'm going to find your house and stab you in the penis

If it travels 38,000 m in 10 seconds it is indeed moving at 3800 m/s.

38000 m / 10 s = (38000 / 10) (m/s) = 3800 m/s.

It sounds big because your ship is ridiculously huge.

Why do you must nerdify random scifi with REAL LIFE MATHEMATICS, mr. 42689?

Star Control II never did that. Might be the reason why it was grrreat.

Play Planescape Torment.

But I'm pretty sure it's not that huge, is what I'm saying.

The distance covered in the third picture (chinua achebe notwithstanding) is about the length of a modern-day battleship. Something going 8,000 miles an hour would not need a full second to fly over something that size.

"Modern-day battleships" (which don't exist, no navy in the world still deploys battleships and even battlecruisers are rare) are not 3.8 km long.

I'm sorry. I meant a ONE OF THESE, and that it's about that size compared to the human figure.

Yeah, there's nothing wrong with the calculations. 38,000m really is 24 miles (well, 23.6). 370m really is 1/5 mile. 3800 m/s is 8500 mph.

Oh, and the big ship is 38km, not 3.8km. So, even more out.

Bottom line, the big ship really is ridiculously big.


[Edit: Oh, sorry, yeah I see where 3.8km came from now. I'll be quiet]

I think the problem here is that you're having a hard time imagining the size of a meter. A meter is a little bit larger than a yard.

So your ship moves approximately 3,809 meters in one frame. That's equal to 4 165 yards, or 12,497 feet. The largest battleship ever constructed, the Yamato, had a length of 862.5 feet.

So, no, your initial calculations were very much correct.

This is what happens when you inspire hl2 porn.

No, I know how big a meter is. I think the problem here lies in the measurements somewhere. Somewhere along the line, it's spitting out inaccurate numbers.

Maybe I need to render out a clip of the spaceship flyby. Because I can tell you for sure it is definitely not 8,000 miles per hour.

Okay guys I just made this picture:



And I was staring at it when I realized what I did wrong.

The man isn't 2 meters tall at all. I accidentally took the dimensions of just his pelvis mesh, which is the parent mesh to rest of the body. All this time I have been comparing the ships to a man with a six and a half-foot tall groin. Fantastic.

PROBLEM SOLVED

But here's that video, just for the sake of it:

The big ship is 38,000 m long. The small ship traverses 38,000 m in 10 seconds. That's 3800 m/s. That is, indeed, 8500 mph.

Like I said, the problem here is perspective. It doesn't "look" like 8500 mph because: 1.) You are a small thing and to you 8500 mph is a big number, and 2.) You are looking at unfathomably huge things from a great distance.

Using the magic of trigonometry I can even calculate how far away the camera is from your picture. Without doing the math I can tell you, though, it's going to be a huge number.

You're not even reading my posts, are you?

I had bad numbers. I wanted to know why they were bad. You told me they were good numbers and I just couldn't tell the difference because they were too big for me. I figured out why the numbers were bad. You still told me they were good numbers and I just couldn't tell the difference because they were too big for me. THX JON

Believe it or not, I am in fact capable of fathoming 4-digit numbers

I started that last post before you replied. I tried to help you work out a problem that was caused by your stupid mistake that you didn't even mention, don't be a douche.

Incidentally, despite my best efforts, your numbers were good. You just couldn't tell that your reference "man" was 56 feet tall. So basically you still don't get it, but now it "looks right" so you're happy.

um if I knew what mistake I made I wouldn't have needed to make a thread about it?

I'm sorry if you think I'm a douche. here's a post someone made on another board that helped me zero in on the problem:


whereas you've just been telling me I'm incapable of imagining the size of my spaceships and effectively ignoring my assertions that the numbers were wrong. that's all.

and yeah, the dimensions were consistent, but only in the software--the measurements identify the mannequin as 2 meters tall, that was a bad number. we found the inconsistency, and fixed it.

Oh. Okay. So let me get this straight:

1.) You showed the guy who helped you zero in on the problem the actual 3D scene, with the two ships and the man. You didn't show it to me.

2.) You never asked why it doesn't "look" right, you asked why you ended up with such a large (correct) answer.

3.) Given the fact that you are apparently incapable of wrapping your mind around concepts as simple as "division" and "multiplication" I have a hard time imagining that your simple intellect would be able to fathom the sheer scale you're dealing with.

4.) YOU NEVER ASKED WHY IT "LOOKS" WRONG. You phrased your question in a profoundly but appropriately stupid way, asking why you ended up with "such a hueg number :downs:" which was in fact correct. If you actually asked the real question you had on your mind maybe someone would have had a hope of answering your question for you.

5.) You got snarky with me for answering the question you asked and confirming your math, you poopy head.

Am I missing anything?

ITT WE ARE ELEMENTARY SCHOOL DROPOUTS

I didn't show the other guy the "3d scene," not sure where you got that. I posted the same thread I posted here. Same pictures, same text. I knew at least one of the numbers had to be bad, I just wasn't sure which one. Of course some of the numbers were consistent with each other, and I'm glad you were able to confirm that. Thanks. Honestly.

And I'm again sorry for being snarky, but you are kind of like, rude. Hard to tolerate for prolonged periods, especially this late. I didn't mean to challenge your alpha geek status or whatever it was that provoked that reaction. I was mostly joking anyway, but I can take down those bits of my posts if you like

So when Jon`C said initially that the large ship was ridiculously big... he was absolutely correct? If you'd stopped and thought about why the big ship was so big, maybe you'd have spotted the problem with your man earlier.

As I understand the problem, it wouldn't be possible to diagnose from the pictures you posted, since we take it on trust that the man is indeed 2m tall and not 50-odd, and we cannot see the length of the small ship in that picture.

Well, thinking about it was what led me to make the thread. The dimensions of the ship on its own were fishy, but not enough to be an obvious problem. The flyby, though, was a dead giveaway (or would be, assuming one took my estimate of the speed it looked like it was traveling at to be reasonably accurate, which it was).

I think the problem here was, like you said, a lack of pictures showing the actual size relationship between the figure and the smaller ship. Apart from the flyby one, anyway. The other board was more oriented toward games and modding, which might explain why they were quicker to notice the discrepancy. That guy in particular was already familiar with 3D apps.

My question is, how could you have not noticed that your reference "man" was huge when you were designing the small spaceship's cockpit area? It looks like you were designing the space around the height of the man as you saw it in the modeling program, but how did you not notice you were building an insanely huge cockpit for only 2-3 people?

haha now he has to redesign the cockpit.

This is the strangest thread I've ever seen here.

Not sure with the program hes using, but he can probably uniformly scale everything down at the same time.

Yeah, that's easy enough

Large spaceship reveals itself to be 3 miles long!

Aww, The much MUCH bigger 38 kilometers (Freaking DWARFING the Executer, let alone anything else) was way cooler.
That things puny.

Impractical, though. It's intended for a comic strip, so making it outrageously huge would be more of a handicap than anything--it's already big enough to make the right impression

Wow. I didn't know you can be banned for being mean to someone at Massassi these days.

Since everything is all well and good now...

Things Fall Apart sux kthxbai

One of my High School English teachers wanted us to read it. I wanted to shoot her after reading two pages.

Thrawn edited his posts before asking the admins to ban me. :downs:

I can put it back, if you prefer?

Easy, because he scaled everything to match a 56ft man by accident. His huge cockpit was perfectly sized for 56ft men!

An honest mistake, and actually it technically doesn't matter what scale you use unless you're trying to get your models to fit an existing scale. He could have gone along using 56 feet men and it really wouldn't have made too much difference until he tried to plunk them into Garry's Mod or something.

..

why did you scale from meters to miles it doesn't make any sense.. metric system is easier anyways.