Hollow pyramid from flat metal pieces: how should I do this?

[HCb]

Hello, I'm trying to draw what I thought would be a simple design but I'm at a loss for how to make it work. What I'm trying to do is to use a 3D model to determine the shape of 4 pieces of flat metal (each identical) which will come together to effectively form a hollow pyramid. I know I want the base of the pyramid to be a certain size (in the drawings I'm using 46 inches). I know I want the sides to be fairly steep (60 degrees). What I'm trying to do is to determine which shape of flat metal would actually come together like this (the point of the flat pieces has to extend to make this happen).

 

I thought doing this in 3D would make it easy to solve this but I don't know how to do it. I've spent hours on this. I've tried placing one part file 4 times and using 4 separate, identical parts (current drawing). I tried editing one part in place and using copy object to get a tool to cut my part with (got me really close but left little artifacts at the corners).

 

What should I try next to get this to work? Is there a whole different method I should be using?

 

Thank you for your time.

 

--HCPyramid.zip

Edited August 23, 2017 by HCb
Solved

[Dadgad]

I have done this in a new drawing, which is in mms, not inches, but it should show you one rudimentary, rather intuitive way to approach it.

 

I never use the PYRAMID command, created the face using a 3D Polyline, but it certainly makes modeling it easy, as long as you know what the height should be along the Z axis.

 

I just realized that you posted this in the Inventor forum, although your profile says that you are using Autocad 2010.

My solution is Autocad based, not sure if it will help you or not.

 

You might want to change your profile USING software, if you usually use Inventor.

I never opened your .zip file, my bad.

Sheet metal pyramid.dwg

Edited August 23, 2017 by Dadgad

[HCb]

Dadgad, thanks for the reply. I apologize for being ambiguous about which product I was using. I am using Inventor for this drawing. I looked over your solution to the drawing in AutoCAD and looks simple enough, if only I'd thought to try that. I understand it better now that I've seen it solved that way.

 

I've updated my information to indicate that I also use Inventor. I came up with another solution, using Inventor, and I'm going to post that in a few minutes.

 

Thank you again.

 

--HC

[ReMark]

You did account for the thickness of the metal, right?

[Dadgad]

No need to apologize, you placed it in the Inventor forum, which was where you meant to post it.

 

I had previously noticed the JD quote which you use as your signature, and JD is very much an Inventor advocate.

Only in rereading your post did I pick up on your mentioning a "part file", which is not vanilla Autocad lingo, I should have figured it out.

 

Glad you figured out how to do it in Inventor.

[HCb]

Okay, I (again) kept at things and finally got a working solution. As Dadgad pointed out, I didn't state which software I was using; it's Inventor 2015.

 

I knew I wanted a funnel which was shaped like a pyramid and which, when viewed from the side, would have angles at 60 degrees. What I wanted was a flat template that represented the individual pieces which needed to be cut to form the pyramid/funnel. I tried a myriad of wrong things then came up with this. First, I drew a 2D triangle with the base width what I wanted the funnel to start out being and with the sides set at the finished 60 degree angle. Then I measured the distance from the point of the pyramid to the center of the base to get the rise. Since this is the profile I want to see from the side, this 2D representation is the same as looking at the completed pyramid from precisely one side straight on.

 

Then, in Inventor, I drew a sketch on a plane (I chose the XZ plane). The sketch represents the base of the triangle and is 46 inches square (in this case). Next, I know that the pyramid needs to be as tall as the triangle shape I drew in 2D which came out to be 39.8372" (or units or whatever). I created a plane which was offset from the XZ plane by that distance. I created a sketch on that work plane and projected the geometry from the square base and placed a Point in the middle of it. I simply constrained it to the center and that was it; done. Next, I did a loft from the square base to the center point to form the pyramid. Lastly, I created a sketch on one of the triangular faces of the pyramid and projected the geometry from the pyramid side onto my sketch which gets me a usable drawing of the face.

 

I'll attach a sample file. Hope this helps somebody.

 

--HC

 

Solid Pyramid Example.zip