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-   -   Anybody given this a test run? (http://www.oldrocketforum.com/showthread.php?t=6005)

tbzep 10-15-2009 08:31 AM

Anybody given this a test run?
 
Open Source (meaning free) CAD software called OpenRocket written in Java so it is multi-platform. It was written for a fellow's Master's thesis. I probably won't be home long enough until the weekend to try it out, but it looks promising. Since it is open source, anyone with the ability to do so can tweak, revise, etc.

Read about it here. Download it and give a quick comparison to RocSim, Space Cad, WinRASP, etc. if you have the desire to do so. It's still in Beta, so there will be quirks and bugs, but judging from the comments, it's pretty nice...except for the one Mac user. :) I've always been a "TLAR" person, but it might be fun to play around with.

GregGleason 10-15-2009 08:34 AM

I started playing with it a couple of days ago. It didn't take me too long to come up with a design, yet unflown. I need to put rockets that have had altimeter flights to see how close it matches reality. It seems to be user friendly so far.

Greg

CPMcGraw 10-15-2009 12:57 PM

I just downloaded it and started playing with it. Thanks for the link!

First impressions...
  • I'm not a Java fan...
  • The design side of the program has some nice features, such as the fin editor.
  • The side view is nice and clean. I think I like the layout of the text data within the view a little better.
  • The program is obviously inspired by RockSim. The general arrangement of the screen elements is the same.
  • I do like the illustrated buttons in the component selection section. :)
  • There is not a database of pre-defined components, so each time you create a design, you have to feed the dimensions into the dialog for that component. :(
  • The version I downloaded (0.9.3) has no motors defined, so you cannot run a simulation. :(
  • I like the graphic simulation of components that RockSim only hints at with "(M)" symbols. The dashed rectangles provide a better visualization of where the component winds up inside the body tube.
  • The saved rocket files have an interesting three-letter extension -- ork, for Open RocKet...

The program has a long way to go, but I think the developer is on a good path. If he would change the program from an interpreted language (Java) to a true compiled language, such as C++ or Free Pascal & Lazarus, the program would run faster; it would still be cross-portable to Mac, Linux, and Windows machines using a compiled language, it just requires multiple binaries. Not really an issue.

I'll keep an eye on it, for sure. :D

tbzep 10-15-2009 02:47 PM

Quote:
Originally Posted by CPMcGraw
[*] The version I downloaded (0.9.3) has no motors defined, so you cannot run a simulation. :(


It is supposed to have motors from thrustcurve.org with it. Maybe he accidentally left it out of the .jar file.

Sounds like it might become a great little program. I hope he keeps improving on it and I also hope some folks take the source code and start tweaking. That's one cool thing about open source programs. :cool:

GregGleason 10-15-2009 04:07 PM

2 Attachment(s)
Quote:
Originally Posted by CPMcGraw

The version I downloaded (0.9.3) has no motors defined ...



Craig,

I appreciate your input since I am not a RockSim user (yet).

Here is a screen shot of a design with the flight sim (some how mine had the motor data).

Greg

CPMcGraw 10-15-2009 04:40 PM

Greg,

I looked (again) at the sourceforge site, and it does indicate the motor files are supposed to be included. I'll dig into it deeper to see if I've missed anything in setting it up.

RockSim is still my choice at present, but a having a good "underdog" alternative would make things very interesting...

GregGleason 10-15-2009 04:45 PM

IIRC, I think to get the motor you had to specify on the tube that it had a motor, like a check box or something like it.

At least with OpenRocket, no one can argue that the price is right! :) For a free program it seems to do a lot. However, for more complex designs it would appear that RockSim is the way to go.

Greg

sam_midkiff 10-15-2009 05:28 PM

Quote:
Originally Posted by CPMcGraw
I just downloaded it and started playing with it. Thanks for the link!

First impressions...
[list]
<snip>
If he would change the program from an interpreted language (Java) to a true compiled language, such as C++ or Free Pascal & Lazarus, the program would run faster; it would still be cross-portable to Mac, Linux, and Windows machines using a compiled language, it just requires multiple binaries. Not really an issue.

I'll keep an eye on it, for sure. :D


No Java that I know of interprets frequently executed and/or long running methods in a program. They are dynamically compiled at runtime. http://blogs.azulsystems.com/cliff/...ance-again.html has an interesting discussion of Java performance by Cliff Click, a smart guy and real Java compiler/performance expert.

Also, use the server VM for longer running apps, it provides significantly better performance that the standard VM, a point made in the above post and something I've observed in my own work.

Sam
Java bigot (but who still thinks computer engineers should learn to program in C.)

stantonjtroy 10-15-2009 06:23 PM

I like this thing. Rocsim is better, no question, But this is a wonderful tool in it's own right.
As for the motor, go to the editor and select the tube you have as a motor tube. click the tab labeled "Motor" and chk the box marked "This component is a motor mount". Now you can hit the "Select Motor" button and select your motor and delay. The major problem is that in order to change the motor you have to go back to the motor mount tube editor. Additionally, when you change the motor it futzes with the data from the first sim run. The sim data is good but it would be helpful if it showed wheather the deployment was pre or post apogee. I do like that there is an option for choosing the CP display. I wave mine set to Caliber. Stability at a glance, gotta love it. It would be nice to know by what means the CP is calculated. As this is a Beta version I can't complain at all! There is a link on the download site to report "Problems" or sugestions. I think in short order this will be a most indespensible tool.

CPMcGraw 10-15-2009 08:01 PM

Quote:
Originally Posted by sam_midkiff
...They are dynamically compiled at runtime...


Sam, that's just a fancy phrase for interpreted scripting. Java is 'pre-compiled' into an intermediate form. But it still means the computer is trying to digest pseudo-code at the instant the program is being run. Conversion from p-code into machine code is still interpretation in my book.

Java may be faster than a 'true' interpreted language, like the early BASICs found on many old machines, but nothing can beat the speed of good compiled code except pure machine code.

Quote:
...computer engineers should learn to program in C...


I'm a C and C++ zealot, so I do have a bias. :D

However, I am trying to comprehend Pascal, and I still have great respect for assembler code...


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