# OpenRocket suggestion

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#### bobby_hamill

##### Well-Known Member
I would like to suggest a new function / add on to OpenRocket .
Can some who is good with code in OpenRocket write a program on designing a decal
for a certain length and diameter airframe ?

It would be sorta like plugging in the known data such a length and diameter of the airframe
and the result would be an answer that would let you know the length and width of the PNG
image file that would fit the airframe .

These steps were written down for me by K'tesh to do it long hand

-----------------------------------------------------------------------------------------------

Make a decal in openrocket

For the decals I've been using lately, I've been creating a .png image that is set at 100 pixels per inch. So a BT-60 based rocket with a 18" body tube gets an image that is 1800x514 (the 514 number was figured as 1.637"xPi). I copy my wraps and other decals onto this image, then use the edit function to correct them if one is out of place. It isn't fast, but the results can be stunning.

PNG image set to 100 pixels per inch

BT-60 x 18-inch long airframe

1800 from 18-inch length

Diameter of airframe times Pi

BT-60 = 1.637 inches x Pi = 514

100 pixels PNG x 18-inch length = 1800

Diameter of airframe 1.637 x Pi = 514

Image to fit BT-60 = 1800 x 514

Thanks for sharing your / @K'Tesh's howto @bobby_hamill !

And thanks for the suggestion too !!

-- kjh

If it was not for K'Tesh I would be still flying naked rockets LOL

Just a clairification... Again using a BT-60 (1.637" OD) as an example.

My calculator puts 1.637 x π = 5.1427871739264915313633472184285

5.1427871739264915313633472184285 x 100 = 514.27871739264915313633472184285

Now since there is no such thing as .27871739264915313633472184285 of a pixel, you need to round to the nearest whole pixel (in this case 514 is the nearest).

OR by default will either compress any overage (say if you wanted to go with 300 DPI), or stretch the 514 pixels to close the missing .27871739264915313633472184285" gap.

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It's Java, it's open source, so go for it!

by the time I learn how to use java openrocket will be obsolete

Hey, can someone add a feature to OpenRocket for designing decals? It would calculate the PNG dimensions based on airframe length and diameter. For example, an 18-inch BT-60 airframe needs a 1800x514 pixels PNG. This would make decal creation easier and more accurate.

Hey, can someone add a feature to OpenRocket for designing decals? It would calculate the PNG dimensions based on airframe length and diameter. For example, an 18-inch BT-60 airframe needs a 1800x514 pixels PNG. This would make decal creation easier and more accurate.
That is the exact feature requested in the first post of this thread, and entered on github here: https://github.com/openrocket/openrocket/issues/1994

by the time I learn how to use java openrocket will be obsolete
It’s not that bad, go watch a YouTube tutorial (over several days there quite long) and stick your head in the code and poke around.

I know how to program and I still avoid Java (except for the simplest tweaks, which are not particularly Java-specific), mainly due to lack of time to devote to it. I don't think it's reasonable to suggest to every feature requester that they go in and code it themselves.

That said, there must surely be some additional Java coders out there who could contribute a bit of effort to the cause. It would be a great help to us.

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