Multi stage rockets

[MajorTom]

Major Tom -

Wow! For a pre-beta, you're produced an exciting piece of work.

I found myself actually biting my nails nervously watching my fuel as the F9-Dragon sought orbit. After my third test, my nervousness slipped away.

Time after time, the F9-Dragon consistently achieves LEO - seamlessly! I can't help but think you've done some outstanding coding for this thing. I'm really impressed.

Keep after this project, will you? I'm looking forward to subsequent releases.

Thank you for the kind words!

Good news, the new numbers, derived after I found some "better" data online last night, work great, don't make me feel like I'm cheating, and even can get my test article into a 52 degree-inclination orbit. See where I'm headed with this...?

Please stay tuned!

MT

 

[MJR]

When you make your tube, either as a simple cylinder or done with "lathe," you'll find that the dialog boxes have options (uncheck them) as to whether they have "caps." I believe the default is "Caps."

In terms of size, have you ever seen a multistage that's 3rd stage is bigger than the second, or first? Big to smaller to smallest. Make sure they're the same diameter, unless you're also making fairing - but even then, the top of a lower stage has to connect to the next upper one. See my link above for the java script rocket designer as well for ideas here. Also see the following post http://orbiter-forum.com/showthread.php?t=1168, and scroll down to the "rocket modeler."

For your question about axis - notice on the bottom left corner of Anim8or's work surface there are two arrows. You can't see the third because you're on the same plane. Each arrow represents another axis (X, Y if you're in Front view). If you switch views (i.e., Top) that third arrow will become visible, but one of the others will disappear.

I think it is bigger than the second. I will try that and later I will get help from MajorTom to add exhaust and other things. Thanks guys. Also, when I am ready to make it appear in Orbiter, how do I complete the steps necessary for it?

 

[n0mad23]

MJR -

Be prepared for headaches and many failed attempts (if your experience is like mine).

After your model's done, it needs to be exported as a mesh (through Object-Export), then it should probably be revised with a utility like Mesh Wizard. Urwumpe's made a fabulous mesh-export utility for Anim8or that you should probably use. Groups using the same materials (and close to each other) need to be consolidated (makes the file smaller) and you'll probably need to find some vector locations (x,y,z) for docking ports, attachments, etc. Mesh Wizard works really well for these things.

You'll need two copies of your mesh. One is the one you'll put in Orbiter's Mesh dir - the other you need to run Shipedit.exe on (find this in Orbitersdk/utils/). It's important that this is NOT the one you put in the mesh dir, as all groups are removed - and your textures will disappear.

Shipedit.exe will give you aproximate cross-sections and PMI readings. These need to be included in your .cfg or .ini file.

You need to convert your .bmp's to .dds files (you know about this from another thread). These need to be imported into the Textures dir.

Configuration and initialization issues should be addressed when it's time, as there's plenty to keep you occupied for now.

For the knowledgeable - have I forgotten anything here?

 

[MJR]

Thank you very much. I will try to do all of this.

 

[MJR]

Do I export it with all of the files as one object in Anim8or? Insted of exporting three different stages?

 

[MJR]

Does this look okay?

I think I am missing a stage. If I am, correct me on this.

 

[n0mad23]

Each stage will have to be exported as a separate mesh (with different names).

I'm out of my comfort zone here, as I haven't done multistage work at all. But luckily, I just got done reading both Multistage and Spacecraft3 docs yesterday - so I'm confident about each stage (and each fairing if used) needs to be an independent mesh. These will be connected by an .ini file (see Config/Multistage/demo.ini for an example), and I'm guessing some entries in the .scn file as well. But here I'm guessing.

 

[MJR]

What do I copy off of shipedit?

 

[n0mad23]

Shipedit.exe will give you aproximate cross-sections and PMI readings. These need to be included in your .cfg or .ini file.

This.

 

[MajorTom]

Hi guys,

Actually, you don't need PMI and cross section values for multistage2, but you do need them for spacecraft3. Save this step for your payload, which you'll probably want to use with spacecraft3, which will be needed once you jettison the spacecraft payload from the final, upper stage.

EDIT: You know what, I think that the diameter and length values you provide in your *.ini file are used by multistage2 to set PMI & cross section, also size.

I'm compiling a set of design notes, or a "tutorial" if you will, on Multistage, and will include it with the documentation with my beta2 F9/Dragon. MJR, this might help you understand all the steps involved, but I don't get too specific on how to create meshes and textures. That's the "artistic" side of add-on development, and...beauty is in the eye of the beholder

I've put some more work into the meshes, guidance file and scenarios since last night. I want to do a little bit more then I'll update the beta on the hangar to beta2.

G'nite!

MT

 

[n0mad23]

Far out.

I love learning new things. I'll be looking at the designer notes as well, as it'll be a good opportunity to have a look at multistage.

I have a feeling by the time I'm done with the current project, a multistage of some sort will be part of it.

 

[MajorTom]

Does this look okay?

I think I am missing a stage. If I am, correct me on this.

MJR,

A picture is worth a thousand words...so I've uploaded one that isn't copyrighted, to indicate where the stages are.

Save each stage as its own mesh file, and give them appropriate names, like F9-stage1, F9-stage2, etc.

Also, study the stages I put together in the beta release to get a feel for the proportions, including engine sizes. There is a great big engine on stage 2, contained by the interstage that I believe will be attached to stage 1 (but that engine is hidden in this photo).

MT

 

[MJR]

I am curious how large the first stage is. So the 2nd and 3rd are pretty small? I don't know if I am ready for making the payload but all I want to do is make a first, second, and third stage. Thanks for the help.

 

[MajorTom]

Howdy,

Here's the value of my diagram! First, you'll notice there is no third stage.

Second, though it sounds terribly crude, here's an opportunity to guess the lengths of the various pieces: eyeball them. I'd even use a ruler held up to my PC screen. Crude, but probably correct within 5%. First, measure overall length. Write that number down. Then measure the length of stage 1, then interstage, then stage 2, then payload. Then divide each of those numbers by the overall length. Multiply those quotients by 54 meters (the actual F9 overall height) and you'll be very close.

Then you'll have an approximate understanding of the heights of the parts. But use every piece of data you can find to refine these initial estimates.

I haven't released my "tutorial" on multistagers yet, but there I claim that mesh and texture development is to a large extent "eyeballing" when you've not got great data available.

Have fun!

MT

 

[n0mad23]

MT-

Since you admitted it first, I will, too. I eyeball a lot of my work.

Only if it's an issue will I do measurements - and there are objects that need this kind of attention. For my current project, mass is terribly important, so my containers become equally so. I need to know just how much water they can hold and how much that water weighs. When the water is replaced by lunar basalt, I need to know that weight as well.

A ruler to the computer screen! I thought I was the only one!

Cheers.

 

[MajorTom]

Gosh, I'll admit further...my creations are made of nothing more than crinkly bits and smoke!

:rofl:

Just posted an update...beta 2...but didn't test it. Now my repute has hit rock bottom (oh wait, Tex doesn't allow negative reputations. Phew!)

Toodles

 

[n0mad23]

You haven't brought in the mirrors yet?

I'll further admit, it took me a while to give up on the glue and tape. I really wanted to weld and bolt everything.

Best to make rivets from bitmaps after all.

 

[MajorTom]

No, my friend, mirrors are for dll developers...I ain't in that league yet.

****BREAKING NEWS******

I've been busy. Couldn't help myself...this project has acted as a highly enjoyable distraction from other things I ought to be working on. Anyway! I have just published Beta 3. It's much "betta" than Beta 2. Fully Animated Dragon. Better scenarios. Improved meshes and textures.

[ame="http://www.orbithangar.com/searchid.php?ID=3308"]Falcon 9 - Dragon Beta 3[/ame]