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+-- Thread: Math genius needed, geometry (/showthread.php?tid=7347471)
Math genius needed, geometry - Cooler - 04-03-2019
Is there any way to calculate the angles for this star? I'd like to make a large one for indoor use out of 3/4" MDF using just glue to assemble it. I was good at geometry in high school but it was nearly 60 years ago and this is pretty complex. I can figure out the angles for the points and interior corners of the star (as if it were a flat piece).
But how to figure the angles for the 3D depth?
It seems like a pretty easy project once the angles are finalized. Just cut, glue and tape (for clamping), and then paint.
![[Image: generous.jpg]](https://cdn1.ykso.co/destinationhome/product/barn-star-24-inch-metal-indoor-rustic-farmhouse-americana-hanging-dimensional-shabby-chic-distressed-wall-d-cor/images/c9f3c91/1551197276/generous.jpg)
I can easily make one of these, but it is not what I want. And I want the star to cover a large area of the wall about 36" across.
![[Image: il_340x270.1442743226_m8rm.jpg]](https://i.etsystatic.com/8867843/c/1040/826/96/131/il/2e9fa7/1442743226/il_340x270.1442743226_m8rm.jpg)
RE: Math genius needed, geometry - mad_planter - 04-03-2019
(04-03-2019, 08:01 AM)Cooler Wrote: Is there any way to calculate the angles for this star? I'd like to make a large one for indoor use out of 3/4" MDF using just glue to assemble it. I was good at geometry in high school but it was nearly 60 years ago and this is pretty complex. I can figure out the angles for the points and interior corners of the star (as if it were a flat piece).
But how to figure the angles for the 3D depth?
It seems like a pretty easy project once the angles are finalized. Just cut, glue and tape (for clamping), and then paint.
http://lmgtfy.com/?q=calculate+angles+for+3d+star
this site has a xls file to calculate them:
https://www.lumberjocks.com/Aggie69/blog/33374
RE: Math genius needed, geometry - Phil Thien - 04-03-2019
Draw it in SketchUp and measure the angles.
RE: Math genius needed, geometry - Roly - 04-03-2019
Will also need what is the depth to figure the compound miters . Roly
RE: Math genius needed, geometry - FS7 - 04-03-2019
There should not be any compound miters. You might be overthinking it.
RE: Math genius needed, geometry - Arlin Eastman - 04-03-2019
I am pretty sure since I do wood turning it goes all by 360 degrees.
You have 5 points with 2 sides which = ten sides
So 360/10=36 degrees each side
RE: Math genius needed, geometry - DaveR1 - 04-03-2019
Like Phil, I'd model it in SketchUp to get the angles. Precise without calculations.
RE: Math genius needed, geometry - Cooler - 04-03-2019
Thanks for the video links. I think I have enough to start figuring out the angles. I will make a small one to test my math, then the large one. Should be fun.
RE: Math genius needed, geometry - Handplanesandmore - 04-04-2019
News to me that these days, every woodworker uses Sketchup, or knows how to use it!
Simon
RE: Math genius needed, geometry - Admiral - 04-04-2019
(04-03-2019, 11:42 AM)Cooler Wrote: Thanks for the video links. I think I have enough to start figuring out the angles. I will make a small one to test my math, then the large one. Should be fun.
That looks like a great project. I'm math challenged, so please post the result, and the measurements, when you are done. I'd love to make one.