Openrocket Decal Problems

[Co-leader of the LRP]

I have been creating another rocket design in OpenRocket, and it seems good design wise. I wanted to put a Decal on it, and so, following
an openrocket decal guide I found here on TRF
Everything went mostly OK. I designed the decal in paint.net and I'm happy with the way it turned out. However, there's one problem. The decal is too big on the rocket. I tried shrinking it in the design program and then re-saving that, didn't work. So when I try to scale it in openrocket I run into another problem. Say the decal says Rocket. If I try to scale it down one way, it starts repeating like this: RocketRoc and so on as I make it smaller. If I try to scale it down the other way, it appears on both sides of the rocket. What should I do? Can someone help me with this?

 

[Co-leader of the LRP]

It took me about 20 minutes to figure out how to link the other thread like that in my post. I guess I'm just not very good with computers, which I already sort of knew.

 

[neil_w]

https://www.rocketryforum.com/threa...ther-support-question-for-that-matter.157409/

 

[Co-leader of the LRP]

https://www.rocketryforum.com/threa...ther-support-question-for-that-matter.157409/

I think I've provided enough information, and I can get pictures and a .ork file up later. If anyone tphas a question because I didn't provide an important little tidbit of info, please ask away.

 

[neil_w]

Post the ORK file and I will look at it.

 

[K'Tesh]

Ok... Co...

Here's the deal... Any decal you put on an OpenRocket sim will need to be on a graphic that can completely cover the entire part it's applied to. For example... You want to put a single dot of color on a 18" long BT-60 body tube of a different color. Your graphics file needs to be factored to fit the entire surface. I like to go with 1 pixel = 1/100th of an inch in most cases. So a single pixel dot on the aforementioned 18" long BT-60 needs to be applied to a graphic of the background color that is 1800 x 1.637(Pi), where 1.637" is the diameter of the body tube. Doing the math (and rounding to the nearest whole pixel (you can't do partial pixels)) makes that 1800 pixels x 514 pixels.

Sometimes with a very detailed scan of a decal, I'll bump that to 200 pixels or 300 pixels per inch. Sometimes that's too large for the software to handle, and I need to go back to a smaller graphic. Metallic color samples that are grainy have huge files associated with them and can easily be too large for the .ork file to be shared here.

For a fin, You can't just have your graphic be the length of the root edge x the fin's span*. It has to completely cover the fin. So, if a fin sweeps forwards and/or back from the leading and trailing edges of the root edge, that additional width must be added into your image's size calculations... AND any fin tab that the fin has ALSO needs to be factored in to accurately represent the desired appearance.

*Unless the decal/graphic is a simple horizontal line (or series of lines) parallel to the root edge. However, the fin tab still needs to be factored in. OR will stretch your graphic across the entire fin.

 

[neil_w]

Also: if the texture is set to “repeat” then you’ll get multiple copies when you scale down.

But setting the decal to the correct size (as described by K’Tesh above) will save you this problem.

 

[neil_w]

It took me about 20 minutes to figure out how to link the other thread like that in my post. I guess I'm just not very good with computers, which I already sort of knew.

I think I've provided enough information, and I can get pictures and a .ork file up later. If anyone tphas a question because I didn't provide an important little tidbit of info, please ask away.

I guess I will need to go re-write that other post, because the message did not get through. I'll try again here.

My purpose in creating that other post and linking it here is not to be a jerk and/or scold you. It is simply to help you (and others) understand how to ask a computer question in such way as to maximize the chance of getting a correct answer quickly, without putting undue burden on the helper(s) to try to guess about your situation or expend effort trying to pry the relevant information from you. This is not always obvious to folks who have not had to provide technical support or deal with bug reports.

It is a courtesy to the helpers (either volunteer, as is the case here, or otherwise) to make their job as easy as possible by expending just a bit more effort when posting your question or reporting a bug.

Even if it is not possible to take this approach for this particular question (it's already posted, you're not in front of your OR machine right now, whatever), I hope you will consider it for the next one. It just makes things go smoother for everyone.

 

[Co-leader of the LRP]

Ok... Co...

Here's the deal... Any decal you put on an OpenRocket sim will need to be on a graphic that can completely cover the entire part it's applied to. For example... You want to put a single dot of color on a 18" long BT-60 body tube of a different color. Your graphics file needs to be factored to fit the entire surface. I like to go with 1 pixel = 1/100th of an inch in most cases. So a single pixel dot on the aforementioned 18" long BT-60 needs to be applied to a graphic of the background color that is 1800 x 1.637(Pi), where 1.637" is the diameter of the body tube. Doing the math (and rounding to the nearest whole pixel (you can't do partial pixels)) makes that 1800 pixels x 514 pixels.

Sometimes with a very detailed scan of a decal, I'll bump that to 200 pixels or 300 pixels per inch. Sometimes that's too large for the software to handle, and I need to go back to a smaller graphic. Metallic color samples that are grainy have huge files associated with them and can easily be too large for the .ork file to be shared here.

For a fin, You can't just have your graphic be the length of the root edge x the fin's span*. It has to completely cover the fin. So, if a fin sweeps forwards and/or back from the leading and trailing edges of the root edge, that additional width must be added into your image's size calculations... AND any fin tab that the fin has ALSO needs to be factored in to accurately represent the desired appearance.

*Unless the decal/graphic is a simple horizontal line (or series of lines) parallel to the root edge. However, the fin tab still needs to be factored in. OR will stretch your graphic across the entire fin.

Also: if the texture is set to “repeat” then you’ll get multiple copies when you scale down.

But setting the decal to the correct size (as described by K’Tesh above) will save you this problem.

Thank you, @K'Tesh, I will try to do that next time I have to make a decal. And, @neil_w, i didn't know that, so I will make sure it's not set to "repeat" this time and in future times.

 

[Co-leader of the LRP]

I guess I will need to go re-write that other post, because the message did not get through. I'll try again here.

My purpose in creating that other post and linking it here is not to be a jerk and/or scold you. It is simply to help you (and others) understand how to ask a computer question in such way as to maximize the chance of getting a correct answer quickly, without putting undue burden on the helper(s) to try to guess about your situation or expend effort trying to pry the relevant information from you. This is not always obvious to folks who have not had to provide technical support or deal with bug reports.

It is a courtesy to the helpers (either volunteer, as is the case here, or otherwise) to make their job as easy as possible by expending just a bit more effort when posting your question or reporting a bug.

Even if it is not possible to take this approach for this particular question (it's already posted, you're not in front of your OR machine right now, whatever), I hope you will consider it for the next one. It just makes things go smoother for everyone.

It's OK. I've never been great at understanding the meaning of what is being said/written and getting my meaning acrosss/describing things to people. For instance, I never thought that that post was scolding me in any way. In fact, the quoted post sounds slightly scold-y to me, but that's probably just me being weird.

 

[neil_w]

No worries.

 

[Co-leader of the LRP]

Issue solved. Not too much of an issue now that I know how to stop the decal from repeating. I would put photos and a .ork file here, but I already posted it as the second design over on my design thread so I just linked it there instead.