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3D Stars #1: Program for Calculating Dimensions and Angles for 3D Stars

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Blog entry by Aggie69 posted 619 days ago 7893 reads 17 times favorited 10 comments Add to Favorites Watch
no previous part Part 1 of 3D Stars series Part 2: Compound Angle Cutting Jig with Hold Downs for a Radial Arm Saw »

Have you ever seen a 3 Dimensional star that you really thought was pretty – perhaps on the side of a barn, in someone’s house, or even a Christmas decoration? As a woodworker you may have thought “I’d like to try making one like that.” When you research 3 dimensional (3D) stars on this forum or on the internet as a whole, you’ll be disappointed in what you find. If you’re lucky, you may find a project or two that talks about a specific sized star with fixed dimensions and if you’re really lucky a specific type of tool to make it with! Most of us could easily make a 3D star with the tools we already have in our workshop and could design and make jigs or sleds for easing the job. The BIG PROBLEM - how do we figure out the compound angles necessary???

I got frustrated when I couldn’t find anything on the internet to help me calculate the dimensions and angles necessary to build the shape and size star that I WANTED TO MAKE. High school trig and geometry are 40+ years ago, but with a little refresher reading and some old fashion “keep beating on it til it works”, I developed some equations for calculating the information that I needed. Working with Excel spreadsheets is a lot newer than high school, so I combined my experience with that and the equations to automate calculating dimensions and angles for 3D stars. I developed the equations for a 5-point star and coded them in Excel. I decided that it would be easy to generalize the equations from a 5-point star to an any point star, so I revised my Excel spreadsheet to do just that. It will handle 3 to 8 pointed stars. I also wanted a way to visualize what a star would look like as dimensions changed, so I added a star plotting feature as well. The program is VERY simple. It requires only three user specified variables – the length of one star point, the length from the center of the star to the intersection of two adjacent star points, and the height of the center of the star above the plane the star sits on.

Like most good woodworkers, I enjoy sharing what I’ve done with other woodworkers – for FREE. Below is a link to my Excel spreadsheet. Note that you’ll have to have access to Microsoft Office – Excel to use the spreadsheet. Also, to view the star plot you’ll have to allow your copy of Excel to use Active-X controls (turned off by default because of security issues). Otherwise, everything else will work except the plotting.

You can download a copy of the program here –
3-D Star Calculator.xls

You can also view or download an Adobe PDF file of what the program looks like here –
3-D Star Calculator.pdf

I hope you enjoy the program. I would appreciate feedback about the program and would like to see some STAR Projects.



10 comments so far

View iltws2's profile

iltws2

25 posts in 951 days


#1 posted 619 days ago

Go to my blog on making a Texas Star. I think it will help in what your trying to accomplish. You still need to make patterns and that would be done with your program. Put your program and my technique together and you have a winner.

-- Medicaid Carpenter

View Hugh's profile

Hugh

63 posts in 1761 days


#2 posted 554 days ago

Thank you for creating the spreadsheet. I just started to figure out how to make a star then low and behold I found your post. It is very helpful and appreciated. Would it be posible to print the star as a layout at least a small one that would fill up a sheet of paper? Thanks.

-- Magnolia, Texas

View Aggie69's profile

Aggie69

22 posts in 627 days


#3 posted 554 days ago

Being able to print a scaled image to paper would probably need to be done outside of Excel. The programming is more complicated and time consuming than I want to tackle. Using the spreadsheet itself, you can print the picture of the star that the spreadsheet generates to a single sheet of paper along with the various dimensions and angles. That’s what I do and then I have one piece of paper in the shop with everything on it that I need to make a star.

View MarkTheFiddler's profile

MarkTheFiddler

1766 posts in 815 days


#4 posted 379 days ago

Howdy – THANK YOU!!!

I was looking through the projects earlier for tips on making a 2D star. I should have looked through the forum topics. I got a prototype 2D star done. Next is a 3D star. I’ll try out the calculator next tme.

-- Thanks for all the lessons!

View gwilki's profile

gwilki

16 posts in 100 days


#5 posted 100 days ago

I’m very new here – just joined this morning. I found this thread and looked into downloading the two files, but I was blocked by the site. Have the files moved since you posted them, Aggie?

-- Grant Wilkinson, Ottawa ON

View Aggie69's profile

Aggie69

22 posts in 627 days


#6 posted 100 days ago

The files not downloading was a security issue with a change that Dropbox made earlier in the month. Thanks for bringing it to my attention. The issue has been corrected and the files should download just fine now.

View gwilki's profile

gwilki

16 posts in 100 days


#7 posted 99 days ago

Thank you. I have them.

-- Grant Wilkinson, Ottawa ON

View mcsauer's profile

mcsauer

2 posts in 67 days


#8 posted 67 days ago

I’m not able to open the Excel file. I get a message that says it is encrypted. I would really love to have the calculator!! Can you help?

View Aggie69's profile

Aggie69

22 posts in 627 days


#9 posted 67 days ago

I just downloaded the program from the same link that is posted and it opened just fine. The file is not encrypted, only the behind the scenes visual basic program is password protected since no one really needs to be messing with it. Try downloading it again. Send me an email, rather than a post, if you continue to have problems. To send me an email, click on “Home” next to my profile picture and select “Send Email”.

View mcsauer's profile

mcsauer

2 posts in 67 days


#10 posted 67 days ago

I can’t send you an email because I don’t have 5 posts yet. My guess is that the problem is that I am trying to open it with a Mac version of Excel, and I think it has to “import” it, rather than just open it. I will try on my PC at work.

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