Meshing Question Noob question on making a rocket interstage

[Cosmic Penguin]

Hi all. I'm sounding like a noob here, but I've problems with making a certain feature in anim8or. It's an interstage with provision of "hot-firing" of the second stage engine, with the grids in a triangular structure around the first stage. This can be seen in the Soyuz, the Proton and the rocket I'm trying to build (see attachment).

Can anyone here teach me how to make it? I can't make it into a regularly-spaced grid, only chaotic ones. Thanks! :tiphat:

GPS

 

[N_Molson]

Use mirroring and take advantage of the center of symetry. For exemple :

1) Build two rings that will support the lattice structure (one at the top, one at the bottom).

2) Use cylinders (with not too much sides) to make triangles. Two cylinders will share a common point located on one of the rings (you should have a V). Place that "V" so that the common point is on X=0 or Z=0.

3) When you have adjusted them, convert the cylinders to meshes, then use mirroring. You will have a similar V at the opposite of the circle.

4) Then you group those two "opposite V", copy-paste, and rotate them. You have to make several attempts to find the good angle.

5) Repeat the process. You will have "VVVVV". The challenge is to make sure you will not have a "gap" somewhere. Some calculations can help.

6) When you have your "circle of VVVVV", copy-paste it, then flip it by 180° vertical (Y). You should get a full circle of "XXXXXXX", which makes a nice lattice structure.

Edit : wait, I'll post some pictures to illustrate this properly

 

[Cosmic Penguin]

Use mirroring and take advantage of the center of symetry. For exemple :

1) Build two rings that will support the lattice structure (one at the top, one at the bottom).

2) Use cylinders (with not too much sides) to make triangles. Two cylinders will share a common point located on one of the rings (you should have a V). Place that "V" so that the common point is on X=0 or Z=0.

3) When you have adjusted them, convert the cylinders to meshes, then use mirroring. You will have a similar V at the opposite of the circle.

4) Then you group those two "opposite V", copy-paste, and rotate them. You have to make several attempts to find the good angle.

5) Repeat the process. You will have "VVVVV". The challenge is to make sure you will not have a "gap" somewhere. Some calculations can help.

6) When you have your "circle of VVVVV", copy-paste it, then flip it by 180° vertical (Y). You should get a full circle of "XXXXXXX", which makes a nice lattice structure.

Edit : wait, I'll post some pictures to illustrate this properly

Thank you! :tiphat: I did it without the pictures, the result is shown below.

Now off to ask how to make a correctly-scaled texture.... :facepalm:

GPS

 

[PhantomCruiser]

I was going to say just what N_Molsan said...

But on the same note about a static fire test... I'm looking for the article, but one of the worst space-related disasters was when a Soviet 2nd stage ignited on the pad, burning through and into the first stage; thus igniting the fuel, causing explosion and killing a very good many people. The article is on www.russianspaceweb.com somewhere, and I'll link to it once I find it.

 

[Loru]

Now off to ask how to make a correctly-scaled texture.... :facepalm:

GPS

My method:

Find circumference and compare it to height

If they're roughly the same you can use just cylinder mapping of square (eg. 512x512) texture.

If they're not, use "height to circumference" to determnine width of your texture.

Then create bitmap with height being power of 2 and width you've calculated (eg. 512 x 300) and when you're done with drawing texture just rescale it to square.

 

[N_Molson]

Lattice structure tutorial

OK here are the pictures anyway :

The red ball indicates the center of coordinates (X=0 ; Y=0 ; Z=0)



1) We make our two rings that will be the structural frame of the thing. Those are two very flat cylinders without caps. Convert them to mesh and use the "Shell" button to give them a thickness. Make only one ring and copy-paste it to make sure the two are identical.



2) We begin with 1 cylinder that connects the two rings.



3) Then we apply a "custom rotation" to take into account the curvature of the circle. Mostly trial and error.



4) We copy-paste and rotate the cylinder. We apply a Y=160° rotation (180° - 2 * 10°, because we applied a X=10° rotation at the previous step).



5) Now we adjust the location of the cylinders so that we get our perfect "V".



6) We convert the two cylinders to meshes and click on Build->Join solids. Now the "V" is only one mesh.



7) Now we can mirror the "V" on the Y axis. Perfect symetry.



8) We group the two "V". We don't apply "Join Solids", which can't be reverted. Group is fine enough here.



9) Here I take an "arbitrary" rotation angle that solders the V in a near-perfect fashion. We repeat the copy-paste-rotate process as much as we can. But maths suggest us we're going to run into an issue.



10) No matter, we run straight into the wall ! And we get a "gap" in the pattern, that is very ugly. Duh.



11) What failed ? Easy : we copy/pasted the V for a total of 5 times, and 360/5 = 36 !! Duh again. The "ideal" angle is 36°. Are we screwed ? No, thanks to Ctrl-Z, its like nothing happened.



12) We backtrack to the first copy-paste-rotate thing and this time, we apply a rotation of X=36°. It fits much better. Notice there are small gaps between the "V". To make everything fit perfectly, I suggest to scale up/down (non-uniform scaling) the original V.



13) Group all the "V", copy-paste all the "VVVVV" pattern, and apply a rotation of X=180°. It works perfectly.



14) Here's a new rocket ready to roar the skies ! Group everything and apply a rotation of X=90°, so that the model will be correctly oriented in Orbiter.


See attachments for the .an8 model

 

[Cosmic Penguin]

I was going to say just what N_Molsan said...

But on the same note about a static fire test... I'm looking for the article, but one of the worst space-related disasters was when a Soviet 2nd stage ignited on the pad, burning through and into the first stage; thus igniting the fuel, causing explosion and killing a very good many people. The article is on www.russianspaceweb.com somewhere, and I'll link to it once I find it.

You are thinking about the infamous Nedelin disaster, where before the first test flight of the R-16 ICBM (strangely related to the Tskylon rocket that I have been trying to find someone to build one), a series of mishaps and violations of safety protocol caused it to explode at LC-43 at Baikonur on October 24, 1960, killing about 100 people.

http://www.russianspaceweb.com/r16_disaster.html

http://www.astronautix.com/articles/therophe.htm

 

[PhantomCruiser]

That's it. And I was doing the Tskylon research to build just that rocket, but elected to do the Kosmos instead (look a bit easier, and that I need to get back to finishing now that I think about it).

When I read the original post that event immediately popped into my mind, and thanks for the link, it's a very good article. I intend to use that material for reference in a safety briefing at work around the topic of human performance.

Now to edge back into something on topic (so I don't have to report myself)...

How do they do a hot fire test of a second stage (given what happened in 1960)? Or is it such a short-duration burn that the risk is negligible?