# How to draw triangles

Please help. I am new to Rhino. I am trying to draw a simple triangle where I want the angles to be 60.8526, 60.8526 and 58.2949. I have tried for hours and cannot get it…

Richard

Since you have 2 angles the same, you could use Curve>Line>Angled, setting a horizontal line as your base line and input your first angle, then mirror that to get the other side.

Thank you, but I don’t understand…I am very new to this.

What Daniel tol you is that your triangle is isocele

I hope you are not new to this or you are very young (less than 10 years old) !!!
So

And read the manual, the help
https://docs.mcneel.com/rhino/6/help/en-us/index.htm#commands/line.htm?Highlight=line

Help, how to breath?

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Hi Richard,

Why do you want those specific angles? What other constraints do you have? Have you figured it out yet?

Good luck with your journey into the world of CAD and Rhino

I am building a truncated icosahedron out of 3/4" Birch plywood.

It has 180 triangles made into 30 hexagons and 20 pentagons.
The bevel and blade tilt angles (miter saw and table saw) are very critical to ensure a perfect project.

The angles are much more difficult to hold throughout the job, much more complicated than the compound miter cuts of something like crown molding.

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Wow! So plenty of spare pieces or 2 partial spheres? What size will it/ they be?

There are generally multiple ways of doing things in Rhino- it can be a case of working out the method which suits your case. Another option would be to draw the lines on the axis and then use the rotate command to get the angle you need. You can snap to the end of existing lines to help join the curves and to select the centre of rotation. You can type the angle you want for the rotation command.

Also you can share your file on here if you would like some help.

A truncated icosahedron has 12 regular pentagonal faces and 20 regular hexagonal faces. What are the extra 18 faces for?

This is my first attempt, the new globe will be about 21 inches in diameter, this one is about 9.

This would have to be turned on a lathe to make it perfectly round.

Tons of work…and many chances for error…even if one bevel is off one tenth of a degree, it won’t work…

I would like to see the people who made fun of me make one of these!

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@rocket2004
Take a look at this: https://www.food4rhino.com/app/rhinopolyhedra
By Dale Fugier

tou·ché.

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I used the rotate command and it works great…thank you very much…

Stellation…so when sanded down the plywood veneers are exposed to create the effect seen in my photo.

Great! Good to know - maybe our brains work in similar ways :). I would love to see the finished item!

Sorry you had to go through that for a simple and very legitimate question. Not cool. The forum guidelines specifically say that simple questions from new users are welcome.

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Yes… please always feel free to post beginner questions here.

-Pascal

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Yeah, that level of accuracy in plywood, especially with manual tools, is very hard, and even on a 5 axis CNC it’s hard because plywood is relatively soft and it’s very easy to crush or deform the pointy side of a miter after you cut it, during assembly.

And then on top of that, if you’re carving your way down through the veneers, it’s kind of a crapshoot as to what you’ll find, because the manufacturing tolerances on the thickness of each individual layer and on the sheets as a whole may not be all that great.

Also:
+1 recommendation for the rhino polyhedra plug in. I use it and love it.

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Thank you. I have the polyhedra plug in. It is great, except I am unable to unroll the objects I import from the plug in. I am able to unroll any object that I create myself, but not the items I import from the plug in. I am doing something wrong.

RR