Rocksim vs. Open Rocket

[AfterBurners]

RS just doesn't automatically update itself. You need to run schedule updates. I check mine for updates every few months. Its not free but I find it more user friendly and besides I have a ton of cash so it really doesn't bother that its only $125. I've used OR a few times and wasn't impressed with it. It has some limitations and who wants to be limited. Apogee offers several Peak of Flight articles that cover some cool things you can do with RS, I doubt OR offers anything similar although I could be wrong? Apogee also offers better service for the software and other products that they sell and online chat. So $125 isn't really that bad considering everything you do get. It's the same difference as paying $1.99 for some Wally World spray paint verses paying $6.99 for some high quality paint for that SV you've been working on. You basically get what you pay for. Anywhoo just wanted to add my two cents One other thing I would like to mention, when you purchase RS you also get some cool rocket design plans that are included that you can scratch build. Just print the parts list and go shopping. Cool stuff!

 

[jqavins]

I purchased RS about 15 years ago if I remember correctly, after using the demo version and OR, each briefly. At that time I found OR clunky and feature poor, and RS was well worth the money in light of the lack of a good alternative. Now that I've paid my money and spent many years using RS I have no intention of going back.

I've read how much better OR has grown. I like having pods, fully tested tube fins, and ring tails, but if I were starting over I don't think they'd be worth the money. I don't think so. But I'm not sure. I can see myself only thinking to use those features rarely, but I can also see myself being very frustrated on those few occasions.

I guess it depends a lot on one's budget. If the price of RS is one's rocketry budget for a year then hell no. If it's half a month's rocket budget then sure, what the heck?

 

[scsager]

Just pointing out the obvious -
Rock sim utilizes 3-degrees of freedom; Open Rocket, 6-degrees of freedom.
For $250 I can install Rocksim on my desktop and Laptop -or- Install Open Rocket on my desktop and laptop *and* buy a 75mm "L" power reload.

If you are not impressed by what OpenRocket can do... try doing a search on this forum for "OpenRocket parts" by member K'Tesh.

The most important point of all - the software is less important than the time and effort you put into customizing the simulation to create an accurate representation of YOUR rocket.

 

[Buckeye]

Just pointing out the obvious -
Rock sim utilizes 3-degrees of freedom; Open Rocket, 6-degrees of freedom.
For $250 I can install Rocksim on my desktop and Laptop -or- Install Open Rocket on my desktop and laptop *and* buy a 75mm "L" power reload.

If you are not impressed by what OpenRocket can do... try doing a search on this forum for "OpenRocket parts" by member K'Tesh.

The most important point of all - the software is less important than the time and effort you put into customizing the simulation to create an accurate representation of YOUR rocket.

K'Tesh makes nice renderings, but for flight simulations, they are useless.

I agree with your last sentence. 99% of problems are user error. However, the more you push the softwares, their flaws are exposed. That's why I use all of them: Thrustcurve, RasAeroII, Rocksim, and OpenRocket.

I'll go out on a limb and say that more new "plugins" have been created by secondary programmers with Rocksim than OpenRocket. Rocksim offers the batch simulation executable, and Apogee opened their XML file structure for the world to see. This enabled new software to easily tap into Rocksim, including OpenRocket which essentially copied it.

 

[dr wogz]

IT lingo:
a PEBCAK issue



(Problem Exists Between Chair and Keyboard)

 

[Bat-mite]

Also known as a "DAO error." (Dumb @$$ Operator)

 

[jqavins]

User Headspace Error (UHE).

I haven't yet run into plugins for RS; can someone point me to any? I'm surprised to learn it's possible.

I've done some hacks on my own, but only working directly on the XML .rkt file, not creating any reusable code (and certainly not anything that can be added into RS itself). I'd love to see if someone has plugins for them

For example, I will sometimes define a fin curve by a formula, compute points in Excel, then write a formula that formats the computed points as RS wants to see them; create the rocket design in RS with a placeholder fin; then edit the .rkt file directly to paste my points list in.)

 

[SammyD]

Rocksim is not worth the ridiculous price tag they charge for it.

Could not agree more with that statement....

 

[Buckeye]

User Headspace Error (UHE).

I haven't yet run into plugins for RS; can someone point me to any? I'm surprised to learn it's possible.

I've done some hacks on my own, but only working directly on the XML .rkt file, not creating any reusable code (and certainly not anything that can be added into RS itself). I'd love to see if someone has plugins for them

For example, I will sometimes define a fin curve by a formula, compute points in Excel, then write a formula that formats the computed points as RS wants to see them; create the rocket design in RS with a placeholder fin; then edit the .rkt file directly to paste my points list in.)

OK, "plugin" is probably not the correct term, that's why I put it in quotes! You cannot plug in to the Rocksim source code itself. "Extension" is maybe a better word. The console solver executable can be run in other applications to do extra stuff Rocksim doesn't do. Splash (became Rocksim Pro, I think) and SmartSim were extension software written by third parties that called the console. Apogee used to market these, but no more. I used to have a batch code that iterated through every motor with RockSim (like Thrustcurve does). And of course, hacking the rkt file is easy to do as well.

 

[grouch]

I haven't opened up my version of RS in years.

 

[DaveRKP]

RS just doesn't automatically update itself. You need to run schedule updates. I check mine for updates every few months. Its not free but I find it more user friendly and besides I have a ton of cash so it really doesn't bother that its only $125. I've used OR a few times and wasn't impressed with it. It has some limitations and who wants to be limited. Apogee offers several Peak of Flight articles that cover some cool things you can do with RS, I doubt OR offers anything similar although I could be wrong? Apogee also offers better service for the software and other products that they sell and online chat. So $125 isn't really that bad considering everything you do get. It's the same difference as paying $1.99 for some Wally World spray paint verses paying $6.99 for some high quality paint for that SV you've been working on. You basically get what you pay for. Anywhoo just wanted to add my two cents One other thing I would like to mention, when you purchase RS you also get some cool rocket design plans that are included that you can scratch build. Just print the parts list and go shopping. Cool stuff!

I'm a relatively new RS user - went that way to get support for booster / glider designs. I cut my teeth with a upscale implementation of an Orbital Transport with some additional tweeks and mods I pondered as I built an original scale version.

I'm interested in what you may be seeing by way of RS updates via your routine checks. My install shows Ver: 9.6.3f228 - is this the latest or is there something newer out there?

 

[AfterBurners]

I'm a relatively new RS user - went that way to get support for booster / glider designs. I cut my teeth with a upscale implementation of an Orbital Transport with some additional tweeks and mods I pondered as I built an original scale version.

I'm interested in what you may be seeing by way of RS updates via your routine checks. My install shows Ver: 9.6.3f228 - is this the latest or is there something newer out there?

That actually may be the latest version. I haven't used mine in a few weeks, but can check later.

 

[Arsenal78]

I have found OpenRocket highly more accurate than Rocksim and it’s much easier to edit parts. Example: I loaded a LOC 4” Goblin into both programs with the same motor and everything, a J435. OpenRocket had an altitude of around 3500 and Rocksim was like 5700.

 

[Buckeye]

I have found OpenRocket highly more accurate than Rocksim and it’s much easier to edit parts. Example: I loaded a LOC 4” Goblin into both programs with the same motor and everything, a J435. OpenRocket had an altitude of around 3500 and Rocksim was like 5700.

Care to share your file?

 

[Doug Holverson]

So how is OpenRocket with BGs and RGs?

 

[neil_w]

So how is OpenRocket with BGs and RGs?

No specific support that I'm aware of. What does Rocksim do?

 

[jd2cylman]

My RS 9 kept trying to update. I could never get an update to finish loading. I'm still on the initial version. All the Apogee tech help shows Apple computer stuff. Doesn't relate to my Windoze system (at least in a way I can understand in my limited experience). TBH, I haven't tried in years to run an update, so maybe I should try again, since ALL my OR files disappeared in the last round of Windoze updates on two different computers no less...

 

[jqavins]

RS just doesn't automatically update itself.

Incorrect, mostly. The shortcut that will land on your desktop when you install RS is to the updater, which checks for a new version then downloads and installs if thee is one and chains to the main program file if thee is not. You can launch the main directly and not get automatic updates, but if you use it as intended you will get them.

 

[AfterBurners]

Incorrect, mostly. The shortcut that will land on your desktop when you install RS is to the updater, which checks for a new version then downloads and installs if thee is one and chains to the main program file if thee is not. You can launch the main directly and not get automatic updates, but if you use it as intended you will get them.

Go to know

 

[jqavins]

I have found OpenRocket highly more accurate than Rocksim and it’s much easier to edit parts. Example: I loaded a LOC 4” Goblin into both programs with the same motor and everything, a J435. OpenRocket had an altitude of around 3500 and Rocksim was like 5700.

OK, OR simmed in lower, but what was the actual altitude when launched? Also, were the launch conditioned the same?

I'm coming to realize that I'm sounding like a real RS booster. It's not really that, it's just that I'm quite content with RS and some of the posts here have seemed dismissive without showing cause. (Having, maybe, but not showing.) It feels a little like an iOS vs. Android debate, with some of the people knocking the one they don't use just because they prefer theirs. (And some offering more considered comparisons, to be sure.)

I only use Android. I had an iPhone once and, jeez, who'd pay that ridiculous price for an inferior product? But I know iPhone/iPad lovers have their reasons.

 

[neil_w]

Clearly, both programs work for lots of people. Certainly no reason for any animosity.

Rocksim definitely supports some things that OR doesn't. For some those features might be worth the money. For others OR is sufficient. Good to have options...

 

[Bill S]

RS also does pods. This has allowed me to sim the TLP Krypton and Estes Intercepter E without any compromising.

I just designed a rocket with 4 side pod tubes with nosecones on it in RS, whereas OR can't do that. Nor can OR do ringtails, which I would like to experiement with. I don't mind paying for abilities I will actually use.

This thing:

 

[mbeels]

Recently I found Rocksim very useful for assessing the dynamic stability of a rocket. Does Open Rocket do that? I don't have any experience with it. I thought the price for Rocksim was very reasonable, and for me, it was worth it. I'm a content customer.

It is great to have options for simulation software.

 

[Nytrunner]

Openrocket has plots of CP and CG shift during flight, as well as AoA graphs

 

[jqavins]

So does RS. RS will let you plot dozens of things, up to... I think the number is four at a time. The graphs are not very well made, but usually adequate. If you find them not to be, you can export any or all of the dozens of data sequences and plot them yourself with the tool of your choice (Excel/LibreOffice, Matlab/Octave, whatever.)

 

[mbeels]

Openrocket has plots of CP and CG shift during flight, as well as AoA graphs

Ok, I was more thinking of longitudinal moment of inertia, damping ratio, angle-of-attack during flight, torque, etc....

 

[jqavins]

Yep, all that. Altitude, speed, acceleration, distance down-range, speed and acceleration resolved into orthoginal spacial axes, all of those for each stage independently, mass, CG, CP, static margin, thrust, drag force, moments of inertia axial and longitudinal, AoA, damping ratio, restoring torque, air pressure, air density, and probably more that I don't recall.

The same list is available for display in a status display synchronized to the simulated flight video. Unfortunately, if I remember right, you can't pick a subset of the massive data dump when you're using it next to the video.

Most of that data is of no interest to most of us most of the time, and to some of us all of the time. But if you want that level of detail you are getting a lot for your money. I don't know what OR has in terms of graphing or exporting such a volume of data; it may be just as complete for all I know, since it has to have that information internally.

My biggest disappointment with RS is that it's 3 DoF. The 6 DoF version (with other features as well), RS Pro, costs a completely outrageous thousand bucks. It was intended for the professional engineering market but, as far as I can tell, doesn't have the thorough testing that that market would demand; I got no response when I asked. Tim used to be a rocket engineer for Boeing, so he ought to know better. I could be wrong, but I think that RS Pro has not sold well.

I didn't know until this thread that OR is 6 DoF; that's a good reason to give it another try.

My second biggest disappointment with RS is a particular bug that I discovered, thoroughly documented, and reported, but which has not been addressed. It's not a big bug, though potentially important especially with hybrid engines. The disappointment is that there's no action after it was reported with detailed documentation.

 

[Cory]

Just go get RASAero 2. IT IS THE BEST!

Going into forum user proof bunker. Good luck with this thread!

 

[Buckeye]

Just go get RASAero 2. IT IS THE BEST!

Going into forum user proof bunker. Good luck with this thread!

Sure, if you don't mind doing your sims AFTER you assembled your motor, installed it, and weighed and balanced the rocket. Repeat for every motor.

 

[Buckeye]

The disappointment is that there's no action after it was reported with detailed documentation.

Like I said, Rocksim is dead in the water. Likewise, OR can't find enough developers willing or able to work on the "Java Jibberish" source code (not my words) and catch it up to the dead software. I am surprised nothing new has come along. I see a big opening for something like consumer-grade CFD, running on GPUs, to enter hobby rocketry.

Most of these threads usually boil down to "Apogee is screwing me. Open Rocket is free." without much discussion of the merits of the software. This thread has more meat, which is good.