Fin shape in OpenRocket and RockSim

[MetricRocketeer]

Hi everyone,

I am trying to model a somewhat complex fin shape in OpenRocket and RockSim. I must say, plotting the points in either of these excellent and amazing programs is somewhat difficult. Doing so in OpenRocket, I find, is even a bit more cumbersome than in RockSim.

Here is my question, please.

I don't want the the first point to have coordinates of (0,0). Let's say that I want the first coordinate to be (0,5). I cannot seem to make this happen with either OR or RS. In other words, I cannot get rid of the (0,0) point and replace it with (0,5).

Does anyone have any suggestions to accomplish this task?

Thank you.

Stanley

 

[neil_w]

In OR at least, first point is always 0,0, by definition. That does not limit you in anyway, it just dictates which point you have to start with.

For complex shapes, sometimes the easiest way is to import an image:

In the image, use white background and a solid black shape for the fin. Try experimenting with it, it works pretty well.

 

[MetricRocketeer]

Thank you, neil-w. I will work on importing an image.

 

[Ronz Rocketz]

In OR at least, first point is always 0,0, by definition. That does not limit you in anyway, it just dictates which point you have to start with.

For complex shapes, sometimes the easiest way is to import an image:
View attachment 456357
In the image, use white background and a solid black shape for the fin. Try experimenting with it, it works pretty well.

I’ve never tried that yet. Does it need to be a scan or can it be a picture?

 

[neil_w]

I’ve never tried that yet. Does it need to be a scan or can it be a picture?

Just needs to be an image with black fin shape against white background. I’m not sure how picky it is about colors. Try it out.

 

[K'Tesh]

I'm on my phone right now (at work), so I can't type. But if you do a search for K'Tesh's OpenRocket tutorials, you should find my tutorial on how to import fins.

https://www.rocketryforum.com/threads/kteshs-openrocket-tutorials.62884/#post-1442663

 

[JoePfeiffer]

I don't want the the first point to have coordinates of (0,0). Let's say that I want the first coordinate to be (0,5). I cannot seem to make this happen with either OR or RS. In other words, I cannot get rid of the (0,0) point and replace it with (0,5).

As Neil said, this can't be done in OR. What are you trying to do that makes it necessary?

 

[K'Tesh]

I'm wondering if the whole (0,0)/(0/5) situation is an attempt to make a fin with a starting point that is located above the body tube... I think the tutorial for adding a fin to a template...

https://www.rocketryforum.com/threads/kteshs-openrocket-tutorials.62884/post-1595653

 

[MetricRocketeer]

Hi K'Tesh,

Thank you. That may be quite helpful.

Stanley

 

[KenC]

Make your second point with the desired x position and 0.0 as the y position. This moves the starting point lower than the 0x:0y initial point. Handy for modeling fins with a point higher on the BT, than the start of the root edge, as on the HyperBat.
.