RockSim pods question

[stealth6]

I'm not figuring out how to do a particular thing in RockSim, so it's time to ask the question here.

Sometimes in the design phase, I'm adding a pod to the airframe. Let's say my AF is a BT80, and the pod will consist of half (cut lengthwise) of a BT50 tube. One way to think of it would be sort of like doing tube fins, but with the "fin" only being partial circumference. The problem is that RockSim can overlap the two tubes, but I can't seem to find a way to discard the portion of the "fin" that would be inside the AF. Refer to the drawing below:

This is looking at the tubes from the bottom view. What I want to do is shown in pic B. What RockSim does is shown in pic A.

So, the question is:
How do I make RockSim give me the results of pic B?

Or more specifically:
If I overlap/intersect two shapes (or tubes), is there a way in RockSim to discard the portion of one of those shapes that is overlapped? Is there a way to cut a tube (or a nose cone, or a tail cone, etc.) in half lengthwise?

As far as basic designing goes, if you do something like this design element RockSim simply ignores that fact that you've got two things in the same 3D space. It lets you get away with it. However, when it comes to doings sims, that excess material (and mass) is there which gives non realistic results. I know that there are ways to compensate for this - to jury rig it essentially - but I'd rather do it accurately if possible.


thanks in advance for your help, s6

 

[SteelyEyed]

I have been concerned about the exact same problem since RS9 was first realeased. If you've seen any of my designs (https://www.rocketryforum.com/showthread.php?t=6471) you know that I use that technique often. Would love to find a solution too...

Bret

 

[stealth6]

Well that's funny/interesting.

I had posted this a few days back, and thought that I didn't get any answers/response - didn't see your post here. So, I kinda shelved the thought for the time being.

Then, just a few minutes ago, I was looking on your thread about your latest build (awesome work by the way). When I saw the pics you posted with the close up of your fillets, I thought, "hey, I bet THIS guy might have some insight to the RockSim problem I posted about - I think I'll pm him and see what he has to say".

So, I checked into this/my thread just to get the link info so that I could include that in my pm to him.

And found your post here. Basically asking the same question I was.

Ah well, I guess we'll both have to wait until someone else chimes in with "the way". I have a feeling that there is no "way" though.


Merry merry to you; your work is inspiring and fascinating; I'll be watching (and learning from) the rest of your build and looking forward to flight reports.

thanks, s6

 

[RodRocket]

You might ask the folks at Apogee Rockets. If it can be done, they would know. And I would be interested to learn how also.

 

[SteelyEyed]

You might ask the folks at Apogee Rockets. If it can be done, they would know. And I would be interested to learn how also.

Yes, that thought crossed my mind too. I even sat in on a RockSim 9 instructions session at NARCON (in Seattle) with Tim Van Milligan speaking. I had so many other questions for him, I never got around to this topic...

Cheers,
Bret