K'Tesh's OpenRocket Tutorials

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K'Tesh

.....OpenRocket's ..... "Chuck Norris"
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Here's my tips on making better looking (and functioning hopefully) sims in OR.

This is the BIG one:

OpenRocket... The Tutorial (A first time user's guide to creating OR (.ork) sims)

And the smaller ones...
Links to the topics:
The Nosecone tutorials (Methods of creating more accurate shapes in OR)

neil_w's Decals in OpenRocket: a not-so-quick and fairly complete tutorial (Turning bland into Beautiful!)
and... Why your fin decals are giving you grief (two words... Fin Tabs)

The Phantom Body Tube (What it's used for... How to create one... And a warning)
Standoffish Launch Lugs (How Not To Use Phantom Body Tubes For Standoffs)
Attaching Fins to Transitions In OpenRocket... (Spoiler Alert!!! It can't be done!!! (but it can be faked))
Attaching Surface Mounted Fins To Curved Transitions (Curved boat tails? Sail right through them with these steps)
Producing Pretty Pictures (Are the CG/CP markings messing up your screen grabs?)
Get out more... A method of spotting problems (Looking at things from a different angle)
Shiny Metallic finishes? ( I might have cracked chrome)
Moving components w/o moving components (Moving Without Traveling)
Making things easy (Why reinvent the wheel... Er... Rocket?)
Another angle on things... (Creating the illusion of edges.)

Color on the inside... (Beauty is more than skin deep.)


So, settle in... I hope you enjoy the ride!
K'Tesh (aka Jim)
 
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So, there's that design you've dreamed of, and you want to sim it in OpenRocket.

You open up OR, and plug in the numbers, and you get something that looks like this...



And that looks nothing like your actual nose cone.


Let's start over with the nose cone... I find that it helps to look at the figure in a 3D finished view. Presumably, that's close to how you actually see things, so it's a good place to begin.

You look over your nosecone and you notice that its point isn't sharp, it's a rounded (ellipse) shape. So you'll need to create a nose cone in OR that is only that size. Trust me, it won't be much to look at yet.






Next is that ogive transition. The measurements tell you that the overall nosecone is X.XXX" long, so subtract that first ellipse length from X.XXX" and plug in the result as your length. You also may need to fiddle with the "Shape parameter" to get the curve just right. I hold my nosecone in front of me, and sight down it with the sim behind it and play with the numbers until it looks right.






Add your shoulder... Now it's looking like your nose cone.






So, you might want to save your nosecone, or continue on and liven things up a little.


.
 
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To liven things up, you'll want to play with the color...

Click the Appearance tab






Uncheck "Use default", and the part turns black.






If you want to change it, click the "Color" (in this case a black rectangle), and a color chart appears.






Select your desired color, then "OK". Next, I like to change the shine to 100% to make its appearance less "flat" (note: the "gloss" appearance won't change until you exit the appearance tab)





Now your nosecone is ready for use in a rocket simulation... You could just save your nosecone file as the part number or common name of it at this point. However, all this work would be nice to share...

So, you'll want to make it more visually accurate when you share it to my Fake it thread.

You'll need to add a body tube that is the same size as the shoulder from the transition, and change its appearance to flat white.






Some nosecones have a tapered transition following the shoulder, and you can simulate those too.






Then take a snapshot of the screen, and crop out the image, upload that to flickr.

Finally, you can add it to my thread, along with the .ork file too.




Mind you, the Apogee PNC-29A doesn't have the taper like that at the back... I've yet to figure out how to replicate its style of shock cord mount.

So, if you make you own passable sim of a nose cone, please add it to my Fake it until you Make it Accurate Nosecone Shapes thread. You never know... Kevin may incorporate it into the next revision.

Oh, I should mention... To use the nosecone's .ork, you'll need to remove that body tube and trailing transition to make it work for a simulated build based on that nosecone.

View attachment 162116
 
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Creating bands of color on a rocket (e.g. decals/paint).

[EDIT] neil_w created an awesome tutorial on decals after I created this tutorial (but this can still help with rapid testing on color schemes)[/EDIT]

Ok, this one is really easy. I wish I thought of it before I did most of my sims (I'm going through and redoing them now).

You have a rocket that has bands of color on its body tube, and you'd like to replicate it... For this example, I'll fix up my Estes Goblin sim.

Estes Goblin (K-55) (using PNC-55AO)


My old way was to "cut" the body tube up into multiple sections...



Problem is, that can cause errors later (as I discovered with my EAC Viper build :facepalm:). So, to create that black band around the body tube, I'll need the body tube to be the full length of the original part.



This simplifies the parts list, and virtually eliminates rounding errors due to OR's limits to three decimal places.

Now to add that band of color... I'll need an "Inner tube" (like a motor mount's tube).



Now, I'll rename it to decal or paint... depending on how the band would be achieved on the real part. I'll also make it the correct length for the band I want.



Next I move it into position... I want it 3 inches from the bottom...

 
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Now I want to make it visible... To do this, I make its OD, the OD of the body tube plus .002 inches, and I'll make its thickness .001 inch.







Lets get a look at it now...






Now to fix the color... Click on the Appearance tab...






Then uncheck "Use default" and the color box changes to black...

17028087645_8b14814497_b.jpg


Oh... but that black is "dull and lifeless"... How about adding some shine... I'll change shine to 100%

 
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If I wanted something other than black, I could double click on the black box, and select from the menu of colors on the next window.







But I'm happy with it. So I'll change the component material to something a little lighter... a custom material I call "Air".







Now that this is done, I can close the window and save the simulation...







BTW You can also use the same procedure to add a painted section of the rocket where the body tube changes color midway down its length.


View attachment Estes Goblin K55 (using PNC-55AO) UPDATED.ork
 
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Ok... Today's tutorial...

How To Import A Fin Into An OpenRocket Simulation Using An Image

When I first started to sim rockets, one of my largest frustrations was getting rounded edges on fin tips looking right. Some people don't even try to represent that in their sims. So, how to I do it? Let me show you...


Let's look at a sim of the Estes Leviathan that someone made a .rkt file of, and uploaded to RocketReviews.






Ok, here's a few things that make me suspect this isn't going to be a very good start... Notice that the "name of the rocket is "Estes Ventris", I'm sure that if they took the time to do overrides on CG and weights they did take some care in doing some things. However, those fins look nothing like what I have in my kit...






So, how do I make the sim's fins look like the real thing?

Actually, it's not to terribly hard, if you have a good scan to work from (see above). After finding, or making my scan of the fins, I open them in MS Paint. It's what I can afford, and not to hard to learn. Then I save the scan as a .bmp file with only 16 colors (less work to do later).





And here's the results...





Now to get to the "hard work". I start by changing the background to a contrasting color (like yellow)

 
Ok, now I'll crop the fins to the root edge...





And the results of that...





Now using the various tools available, I create an outline of the fin in another contrasting color (I like red).





Next, I start to reduce the colors to only two... Black for the actual fin, and white for the space needed in an image to accommodate the fin. I learned that after making the outline, start with cleaning up the extra space first, then work on the fin... Here's a montage...





After getting it to only black and white, I save the results, and have something like this...

 
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Now I'm ready to import the image into OpenRocket... From a Freeform fin, open the shape tab.





I click on the "Import from image" button, then select the template I just created.





Here's the results... The shape is right... But there's something not quite right about it...





Back to the freeform fin tab, where I'll scale the fin to the length of the root edge.





Ok, that looks better...





Can't forget to update the new fin thickness... Again.




And here's the BEFORE and AFTER...





Don't forget to go and add the TTW fin tab back in... You can do that in the "Fin tabs" tab.

Now it's time to fix all the other things that were wrong with the file... (Like the name of the rocket)
 
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The effort that you've made to learn the features of the program and share the knowledge here is admirable. Have you considered contacting the developers about possibly adding some or all of these tips to the Open Rocket package itself ?

"OpenRocket needs help to become even better. Implementing features, writing documentation and creating example designs are just a few ways of helping. If you are interested in helping make OpenRocket the best rocket simulator out there, please Get involved!"

https://openrocket.sourceforge.net/getinvolved.html
 
Creating A Phantom Body Tube (Probably the best trick of OR... However...)

One day perhaps OR will allow us to create fins with -Y (Negative Y) values. We can do -X, but not -Y at this time. Phantom Body Tubes are the way around this. Often they are smaller than the body tube of the part that we are trying to attach it to. Another use for PBTs is fins that are mounted atop other fins (such are found on the AQM-37 Jayhawk, the Mercury Redstone, or Estes Photon Torpedo, among many others). PBTs are really simple to make.

Add a body tube to the end of the body tube of your stage.

Change the diameter to meet the need of your application

Change the width to zero

Change the thickness to zero.

Label it (and what it's used for)

Attach what you need to it.

Save the file.


HOWEVER...

OR will take the PBT into consideration when calculating altitudes. Despite being nothing thick, and nothing long, it will alter the equations of OR, and your altitudes are not so trustworthy any more. Sometimes the results can be off by several hundred (if not a thousand) feet when they are used for raising something off of the body tube (such as launch lugs). As such, I've moved away from using them for launch lugs on standoffs (there's a better trick for that, which I'll explain later).
 
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Standoffish Launch Lugs (How Not To Use Phantom Body Tubes For Standoffs)

Launch lugs on standoffs can be a problem when creating a simulation for rockets that have a larger diameter body tube than the one that the launch lugs are mounted on. To do this, I used to use the Phantom Body Tube. Problem is... They give false altitude measurements. SCARY!!!

There is a better way... Just look inside.


One of the little quirks of OR is the radial offset tab. I didn't know about this until someone managed to "blow up" his rocket in an interesting exploded view. The trick... Internal Body Tubes.

So, how do you use it? It's easy.

Add a Inner body tube to your part that it will be attached to.

Change the dimensions to match the launch lug's length, OD, ID, and position relative to the top or bottom of the component it's being attached to.

And label it.

Now comes the fun part. If your standoffs aren't already at 0 degrees, change one of them to 0 degrees (I like the forward one, less futzing with the fins that way).

Change your view to "Side view", and zoom in until you can see the top of the standoff clearly.

Open up the window for the Launch Lug you've created. Find and click on the "Radial position" tab.

Using the "Radial distance" slider, window, or up/down arrows, adjust your Launch Lug to sit atop the standoff fins w/o a gap or overlap.

If needed, change the "Radial direction" to match the proper orientation of the launch lug. Change the color using the appearance tab to get it to match the desired appearance (or add a decal to it). Then close the window.

If you changed the standoff fin's radial direction, don't forget to change that back.

If you have two standoffs, you can just copy the first LL and paste it to the body tube, and adjust it to the correct location.



Now here's the catch... (Of course there's gotta be catch)

Internal body tubes are not factored into aerodynamic calculations, so they'll have zero drag added to the equation. That said, they'll still be a lot closer to an accurate calculation than using Phantom Body Tubes to get them into the correct position. The difference can be several hundred (if not a thousand (or more)) feet on mpr rockets.

Now aren't you glad you read the fine print?
 
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Using A Phantom Body Tube For Launch Lug Standoffs (This is really easy...)

In a word... DON'T!!!

It messes up your altitude calculations something fierce. DON'T DO It... There's a better way...
 
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The effort that you've made to learn the features of the program and share the knowledge here is admirable. Have you considered contacting the developers about possibly adding some or all of these tips to the Open Rocket package itself ?

"OpenRocket needs help to become even better. Implementing features, writing documentation and creating example designs are just a few ways of helping. If you are interested in helping make OpenRocket the best rocket simulator out there, please Get involved!"

https://openrocket.sourceforge.net/getinvolved.html


Thanks!

Kevin's aware of my work... I have no problem if they want to incorporate it into future releases.

All the Best!
Jim
 
.............Mind you, the Apogee PNC-29A doesn't have the taper like that at the back... I've yet to figure out how to replicate its style of shock cord mount................


What about this?

View attachment 276477

The whole thing is just for show. It affects stability and prevents attachment of the body tube, so it's not really a practical solution if you're looking to replicate an Estes 24 mm nose cone.
 
I can see what you're trying to do, and it looks good.

When it comes to sharing .ork files, I'd recommend that after taking the 3D screen shot, that everything behind the shoulder be eliminated, due to all the hassle it creates when trying to use the file.
 
I can see what you're trying to do, and it looks good.

When it comes to sharing .ork files, I'd recommend that after taking the 3D screen shot, that everything behind the shoulder be eliminated, due to all the hassle it creates when trying to use the file.

Thanks! :)
 
I'm late to the party here, but THANKS K'Tesh! It's golden nuggets like this that keep me coming back each night looking through TRF!
 
Attaching Fins to Transitions In OpenRocket... (Spoiler Alert!!! It can't be done!!!)(but it can be faked)

So, there's a rocket that has you all hot and bothered... The Binder Design Velociraptor is one of mine.



You managed to find the .rkt file on rocketreviews.com, but when you open it up in OR, you get the following message:

· Freeform fin set can not be attached to Transition, ignoring component.

And after clicking "OK" you get an outline of the Velociraptor without the rear fins... Bummer!



Now by chance you manage to find the fin shape somewhere, and you want to attach them to the transition... Sorry buddy, it ain't happening. What about attaching it to the motor tube? Nope... it's an internal body tube, and won't accept them either. So how to get around this?

OR Fin Tutorial 3.jpg

For the Velociraptor the rear fins have tabs that extend down to the motor tube. So, you can attach the fins to the fin can body tube, and then use the position relative to slider to adjust them into the correct position. Oh, and you'll be happy to know that decals applied to the fin that extend into the -Y plane (the fin tab) will show up (so the roll patterns you want to apply to the Mercury Redstone will look ok).


However, with no fin tab, and your fin will look like it's hanging in space...

Blackbrant II RKT fins.png


Thankfully, there's some other options available for you.

The other methods need you to create a phantom body tube. This needs to be 0.0 inches long, and 0.0 inches thick, but the same diameter as the bottom of your transition. You attach your fin to that, and you're golden, right? Well... maybe not so golden...

OR Fin Tutorial 4.png

Your fin's measurements are all relative to 0,0 on an X,Y coordinate system. If the fin attaches to the phantom body tube at a single point (such as found on the Estes Black Brant II), everything forward of that point will be a -X value, and everything behind it will be a +X value (-Y values are not currently allowed in OR). Getting the fins attached is annoying, and slow, but it can be done. For the Black Brant II, it’s easy, the transition has straight sides, and computing the –X values is pretty straightforward.

OR Fin Tutorial 5.png
 
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Attaching Surface Mounted Fins To Curved Transitions (Curved boat tails? Sail right through them with these steps)

But it's not so easy for getting surface mounted fins to follow the curve of a boat tail... Or is it?

My solution to this hypothetical rocket's problem was to go ahead and attach the portion of fin that was at the same "height" (and above) as the body tube to the body tube. The portion that extends below was attached to a phantom body tube. Though the magic of OR's lack of understanding that two objects cannot exist in the same place at the same time, I filled the gap with another fin attached to a phantom body tube.



The results are not that great for getting fin templates, but it does give OR the ability to simulate the appearance.

Now...

If you really want to follow the curve of a boat tail (for a surface mounted fin), you can take screenshots of the rocket in side view, and paste them into an image in an open image manipulation software program...




Then, then edit them together into one image of the fins, and crop out the extra.



Get it down to a single black fin in a white background... and crop it so that the bottom of the fin is touching the bottom of the image...



Save the results...



Then import it into OR and scale it as needed. Just remember that the fin must be attached to a body tube, and that the body tube is the smallest diameter the fin is attached to (this means you'll need a Phantom Body Tube for your fins.

 
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Producing Pretty Pictures....

Ok... So, you've got a sim created for a rocket and you're rightfully pretty proud of it... now to share it with others... But... NUTZ the stupid CG/CP markings are stepping on your hard work.



How do you get rid of those? Can you turn them off in OR? Sadly, the answer is: "nope, not by changing any preferences". So how can it be done? You guessed it... Cheat!

First, right click your mouse, and move the light source to give yourself the best possible colors.... Then get a screen grab ("fn"+"prt sc" for PC users) of the rocket and paste that into your graphics program of choice... Then Crop the image some.






Then back in OR, copy some fins, and place them WAY forward on the rocket... You might need to make them larger to pull that CP forward some, but remember that you don't want to extend the fin's height. To pull the CG forward, change the weight of the fins to something ridiculous (like 10 lbs). A screen grab on this, and paste it into another window of your graphics program. Now you just copy out the part you want to keep...




And paste it into the other image...




Now you just need to align it with the desired image...



From there, you crop your image to just keep what you want... But to prevent getting a faint border like this...




Change the background area to a color that won't conflict with the image or text you want to preserve and crop the image down.




Finally, you change the background back to white...



Save it... Upload it to whatever image sharing site you use (IMHO photobucket SUCKS!, I've never had a Flickr image come up as not found (unless it was actually really deleted by the user), and share it wherever you please.

BTW, that is my interpretation on the prototype of the Binder Design Velociraptor (if you hadn't guessed already). Note the differences in the locations, and sizes of the black and silver bands (as well as the Binder Design logo), and the motor retainer's diameter, shape, and color.

And after closer examination of my photos of the real thing, I feel that the green I used (above) was too light, so here it is again... only darker (perhaps it's too olive)

 
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Get out more... A method of spotting problems (or getting a fresh look at things)

One of the problems I sometimes find with OR is when I change things like the diameter of the motor tube, either by upscaling/downscaling a classic design, or when adapting an existing .ork/.rkt design for a non-standard sizing, OpenRocket's automatic sizing feature doesn't always work the way you expect it to.


attachment.php
attachment.php


I'll be plugging along, when I realize that the centering rings are now set for the wrong diameter. Nuts! Now I have to go and see if the problem exists in other sims.


However, OR has a handy trick that I only learned when SpaceManMat showed me how to make internal components... external.

By using "Inner tubes" to anchor parts (such as bulkhead plates, baffle components, or All-Thread assemblies (All-Thread, nuts, washers)) to, you can keep parts organized. And by using the Radial Position tab on the "Inner tubes", you can adjust them into to their proper location (like for a cluster motor setup), or even right on outside the the body tube.


attachment.php




This is handy for wrapping your head around what's going on inside things like AV bays that are inside nosecones, or motor mounts that go through a transition (like the Velociraptor, the Black Brant II, or the V2). By externalizing the component, you can see how things are aligning, and that might prevent problems later on down the road (like when you are ordering special parts for your build).

attachment.php


Playing around with externalized parts can also other applications...

Binder Design Prototype Velociraptor (exploded view).


attachment.php

Give it a try sometime.
 
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K'Tesh

Question 4 ya .

If you can

How do you export a fin pattern from one openrocket plan into a different openrocket plan ?

Thanks !

Bobby
 
K'Tesh

Question 4 ya .

If you can

How do you export a fin pattern from one openrocket plan into a different openrocket plan ?

Thanks !

Bobby

Sorry I missed this request of yours Bobby...

Go into the file with the fin you want, click on the fin once (it should highlight). Then copy it (Ctrl C)... Go into your other sim, click once on the body tube it's attaching to (it should highlight), and paste (Ctrl P). Easy.
 
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Been puzzling on this for years... Can OR sim metallic finishes? Well... You tell me...

upload_2019-10-14_16-19-22.png

Ok, so it only works on the body tube and the nosecone, but it's a start....

Here's the graphic I used for this BT-50 body tube...

upload_2019-10-14_16-21-39.png

Yep, that's it... 19 pixels high (I could have used 1 pixel high, but, I decided to make it easy on myself.

Now if I could figure out how to do the fins and other parts in this scheme...
 
To liven things up, you'll want to play with the color...

Click the Appearance tab

K'Tesh, I'm doing your OR tutorials and ran into a snag. You show the color change of the nosecone in the design mode but mine continues to be white. But if I look at it in the Photo Studio it shows up as the color I chose. I looked in Preferences & didn't see anything to turn on or off. So what's the trick?
 
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