# ROCKSIM 9 Discussion

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#### jackman

##### Well-Known Member
I've been running it on Windows 2000 and am noticing that it crashes on 2 different PCs that I have. I haven't had a chance to run it on another PC with Win XP yet. The patches seem to be coming out on a fairly frequent basis so I'm hoping it gets fixed at some point or I figure out the workarounds.

#### sj_h1

##### Well-Known Member
Anyone have an older version they are willing to sell? I would love to have it but the price is ridulous. It must work on Vista!

#### rocketguy101

##### Well-Known Member
I just noticed a weird behavior w/ RS9, I opened up an old sim, and selected "Rerun all simulations" to refresh the results. One of the engine combos looked way out of line, so I reran that particular sim, and the numbers came back in line (I was watching the deployment velocity). Out of curiousity, I kept clicking "Rerun all" and the values keep changing.

I deleted all the existing sims and started over. Even with a single set of results, "re-running" will give different values!

Is RS using a random number generator to start the sims?

#### jj94

##### Well-Known Member
I just noticed a weird behavior w/ RS9, I opened up an old sim, and selected "Rerun all simulations" to refresh the results. One of the engine combos looked way out of line, so I reran that particular sim, and the numbers came back in line (I was watching the deployment velocity). Out of curiousity, I kept clicking "Rerun all" and the values keep changing.

I deleted all the existing sims and started over. Even with a single set of results, "re-running" will give different values!

Is RS using a random number generator to start the sims?
I noticed that a while ago with RS8. Not sure why, but after I noticed it, I felt that it would be harder to trust RS8 completely. Not that I did before, as no software can be 100% accurate. But if you have every single value that you can change accurate to your own launching conditions, RS8 is amazingly accurate.

#### cls

##### Well-Known Member
I think the slight variance in results you see is related to random variables, like wind speed. that's a feature. look carefully at the size of the difference in the runs, it's a fraction of a percent isn't it? is that really a big deal?

RS 9 crashes for some reason related to the file suffix association. supposedly there's a fix for that coming out. there's a work around for it too. so that is a dumb but nearly forgivable error.

however, completely unforgivable is RS 9 consistently causes BSODs on my system (XP SP3 and all recent updates) - it's clearly related to 3D drawing of my fancy 3-fins-and-a-nose-cone-rocket because it only BSODs when I select 3D display, none of the other displays cause the issue.

#### rocketguy101

##### Well-Known Member
I think the slight variance in results you see is related to random variables, like wind speed. that's a feature. look carefully at the size of the difference in the runs, it's a fraction of a percent isn't it? is that really a big deal?
The first change was a big deal, because it was showing a deployment velocity of over 100fps w/ a C6-5, and about 38 fps w/ a C6-3. When I re-ran it 2nd or 3rd time, the C6-5 fell more in-line with the C6-3. It was still higher since the optimum delay was 3.5 sec. But that first result caught my attention.

So I guess rule of thumb is to rerun the sims a couple times to let everything settle down?

On your crash, I haven't messed w/ the 3D stuff too much, so I haven't run into that (yet?)

#### cjl

##### Well-Known Member
I noticed that a while ago with RS8. Not sure why, but after I noticed it, I felt that it would be harder to trust RS8 completely. Not that I did before, as no software can be 100% accurate. But if you have every single value that you can change accurate to your own launching conditions, RS8 is amazingly accurate.
Turn the wind off

RS adds a slight wind by default - IIRC, it's something like 3-5MPH, with randomized speed within that range and direction. As a result, there will be slight variance in each sim. It's a nice feature to have, but can be a pain if you are trying to find an exact optimization or something similar.

#### cls

##### Well-Known Member
earlier I wrote:

RS 9 consistently causes BSODs on my system
I updated the video driver (Intel Q35 on mobo, from version 6.x to version 17.x!) and the BSODs stopped happening. plenty of OpenGL changes in that update. so duh on me.

keyboard cut & paste doesn't work for me (XP).

on a positive note:

Has anyone else used the SCALE feature? I think it's awesome. Yesterday I upscaled the Arapahoe E to 4". One click and there it is. The custom fins were upsized properly. Those would have been really difficult to re-draw. Now I know what to do with a BSD tail cone someone gave me ...

how about the external pods feature? I've messed with it a little but not built anything from a scratch design.

#### peter_stanley

##### Well-Known Member
I upgraded a couple weeks ago and like it so far. I think the pod feature is worth the upgrade. This adds a lot of flexibility to the design with not just 'pods', but fins on fins. It (I think although haven't tested) allows parallel cluster flights, with pop-off boosters. This would have saved me a lot of work-around hacks to simulate this in ver. 8 last year.

I also like the ability to scale. This is especially useful for scaling up or down anything with complicated, custom shapes, saves having to recreate them.

I do wish Rocksim had wrap-around fin guides and alignment guides. I always use VCP to print them out. It's not that big of a deal though.

#### TheAviator

##### Well-Known Member
I just noticed a weird behavior w/ RS9, I opened up an old sim, and selected "Rerun all simulations" to refresh the results. One of the engine combos looked way out of line, so I reran that particular sim, and the numbers came back in line (I was watching the deployment velocity). Out of curiousity, I kept clicking "Rerun all" and the values keep changing.

I deleted all the existing sims and started over. Even with a single set of results, "re-running" will give different values!

Is RS using a random number generator to start the sims?
There are several options in RS8 and RS9 that randomize the values. The wind speed will vary by default, but if you set the max and min windspeeds to the same value, then it won't. They also give you the option of having thermals put in the simulation (at random intevals). I normally turn this off because I want dead-air times.

Oh, and just a comment, make absolutely SURE that the "Simulation method" under "Simulation Controls" tab in the flight setup is set to "Fourth-Order Runga-Kutta"! This will ensure the most accurate simulations as Euler's method will accumulate larger errors over time than Runga-Kutta.

#### cjl

##### Well-Known Member
There are several options in RS8 and RS9 that randomize the values. The wind speed will vary by default, but if you set the max and min windspeeds to the same value, then it won't. They also give you the option of having thermals put in the simulation (at random intevals). I normally turn this off because I want dead-air times.

Oh, and just a comment, make absolutely SURE that the "Simulation method" under "Simulation Controls" tab in the flight setup is set to "Fourth-Order Runga-Kutta"! This will ensure the most accurate simulations as Euler's method will accumulate larger errors over time than Runga-Kutta.
True, though for a sufficiently small time step, both simulation methods are plenty accurate.

#### Marlin523

##### Well-Known Member
I have 9 and love it.

#### BRC

##### Well-Known Member
I know this is a bit dated..But know one mentioned RockSim for Mac...SO for what its worth...Not worth it...Way to buggy..The author does not have time to fix bugs as he must first get it ready for Win-7...(Guess ya gotto go to where the money is !!) Apparently its abandoned ware for Mac..(For the time being, I guess ) :confused2:

#### Silverfish

##### Well-Known Member
I know this is a bit dated..But know one mentioned RockSim for Mac...SO for what its worth...Not worth it...Way to buggy..The author does not have time to fix bugs as he must first get it ready for Win-7...(Guess ya gotto go to where the money is !!) Apparently its abandoned ware for Mac..(For the time being, I guess ) :confused2:
I've been using RockSim v.9 on my iMac for a couple of weeks now.... haven't run into any bugs, and am very pleased with it .

Silverfish

#### cwbullet

##### Obsessed with Rocketry
Staff member
Global Mod
It crashed when I try and save it with MacOs 10.6. I did not have that problem till I upgraded to 10.6 from 10.5.

##### Well-Known Member
Have v8 and like it. Don't think I will be upgrading anytime soon.

#### BRC

##### Well-Known Member
I've been using RockSim v.9 on my iMac for a couple of weeks now.... haven't run into any bugs, and am very pleased with it .

Silverfish

Wow... :jaw: Thats pretty cool.. They are there...Tim is very much aware of them, just hasn't addressed them..(yet)..For comparison, try printing from the "Detail Simulation" and lemme know if you need to force quit..?? Thats the most annoying (to me) the others, having to escape (key) to get the buttons to work at least doesn't loose your work...Im using a MacPro..

#### rocketsmith

##### Well-Known Member
Anybody else notice that a 1.14" motormount defaults to 24mm motors? I also can't update: it finds them and downloads but won't install. Many of the sims I have run on simple 3fnc rockets wind up significantly different in real world flight, both way over and way under projected altitude. I even go so far as to measure the weights of finished parts and punch in those numbers. It is a good baseline product, but it is not a professional grade program. As they say,"we don't make money making it perfect. Ship it and we will patch it later." Except mine won't update, so where does that leave me? Better than a notepad and a calculator I guess.

#### Silverfish

##### Well-Known Member
Wow... :jaw: Thats pretty cool.. They are there...Tim is very much aware of them, just hasn't addressed them..(yet)..For comparison, try printing from the "Detail Simulation" and lemme know if you need to force quit..?? Thats the most annoying (to me) the others, having to escape (key) to get the buttons to work at least doesn't loose your work...Im using a MacPro..
Printing the simulation details works fine for me (see the screenshot for proof), and I even used my MacBook Pro for better comparison... I have noticed that the buttons occasionally don't work, but all I do it click on the bar at the top of the window and it seems to free them.

Silverfish

#### BRC

##### Well-Known Member
Printing the simulation details works fine for me (see the screenshot for proof), and I even used my MacBook Pro for better comparison... I have noticed that the buttons occasionally don't work, but all I do it click on the bar at the top of the window and it seems to free them.

Silverfish

The screenshot is as far as I get then have to force quite...I spoke to Tim about it...He said he was aware of the problem but no fix..If it works for you right outa the box, I wonder what the differences are between our setups..?? It is keeping me from purchasing....

#### Blakkzakk

##### Well-Known Member
I just got it yesterday. It seems to crash now and then on Win 7.

#### Blakkzakk

##### Well-Known Member
I still cant get a Mars Snooper to work with real pods on the fins. Otherwise, I like it.

#### Blakkzakk

##### Well-Known Member
Rocksim 9 allows you to change the background pic in the 2D launch simulation window.

I also use a couple of pics of my fave XXX starlets which I refuse to post here.

#### Pem Tech

##### Well-Known Member
Will Rocksim output things like fin shapes in standard CAD file formats? I'm wanting to buy, but also have a friend with SolidWorks, and would like to pass some design info to him.
Not to beat a dead thread about the head and shoulders, but I muddled my way through the conversion process. Export the file as a SVG file, open in Illustrator and export as a DWG or DXF file.

If this is old news, my apologies.....