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I am creating a triangular shaped radio mast and have now created one section of it (see image below with one diagonal 'strut' selected) which I will simply duplicate to create the required height. I have done this with with much difficulty especially rotating the diagonal bars and wondered what would be the easiest method for next time. Creating the diagonal bar on the X axis was relatively easy however on the other two 'sides' was a real challenge as I did this by making a Duplicate of the first one (on the X axis) and then moving it (using G X and G Y) and then rotating which was a real challenge as it was either on the X or Y axis and after moving and rotating ended up with a diamond shaped end section of the bar needing rotating to a square shaped end section. Just wondering what is the easiest way to do this so that hopefully I can do it easier next time.

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John Arnold
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    rotating it 120° on the global Z axis should work fine, no? – moonboots Sep 23 '22 at 07:08
  • Thanks. Yes that works but I find positioning the diagonal a hit and miss as the new diagonal is neither aligned on the X or Y axis and so I G X and then G Y bit by bit to position it. Is there a method to 'lock' the Z axis (or G and both the X and Y) to move it on both the X and Y axis only? Or just trial and error? – John Arnold Sep 23 '22 at 07:24
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    you can put the 3D cursor in the middle of your object (select your object and Shift S > Cursor to Selected), then use it as the transform pivot point so that when you rotate your bar it directly ends up at the right position – moonboots Sep 23 '22 at 07:31
  • I just had another thought ("brain wave"?) while watching tv (I get a lot of ideas when I distance myself from the task). I could rotate everything on the Z axis 60 degrees so that the 'face' with the new diagonal is on the X axis and then it should be easier? – John Arnold Sep 23 '22 at 08:08
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    yep, i think you just have to build "one" side, so one cylinder, two cubes and the diagonal , then join it and, duplicate 2 times and rotate it – Chris Sep 23 '22 at 08:16
  • Sorry I meant 120 degrees. The more I use Blender to model an real life object the more I feel that I need to 'deconstruct' the object (in my mind or as a sketch on paper) – John Arnold Sep 23 '22 at 08:23
  • Just out of curiosity. Assuming this method for making a mast from a 3-sided cylinder is not good enough, could we know what features/profiles/joints etc you need? – Robin Betts Sep 23 '22 at 09:30

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There are many ways to model stuff and no single way is the right one. I think the trick is to know what all the functions do and what to expect from them and think ahead while modelling. When you have enough experience you sort of construct the plan of actions before modelling out of all the available functions. This can only be achieved by lots of practice.

I would model the thing like this: I would create a cylinder but adjust it to have only 3 sides, then I would select the loop(alt+click on an edge in face edit mode) of faces around it and triangulate them, delete only faces to leave only edge, separate the long edges from the top and bottom triangles, then extrude the triangles, bevel sharp corners and use solidify modifier, then convert the edges to curves and add thickness to them by adjusting Bevel property of the curves. If I want square thickness profile, I can lower the resolution all the way to 0 and adjust Tilt of curve vertices to rotate the profile and that is it - there was no need to place or rotate anything because everything was created where it needed to be in the first place.

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Martynas Žiemys
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    A very interesting method. Thanks. Yes the longer I use Blender the more I learn especially from people such as yourself who are willing to spend time showing me other methods. Although I am now well on the way to completing my model I will start another one to use this method for the experience. – John Arnold Sep 23 '22 at 11:55
  • I am now attempting to learn Martynas' method. I get 'lost' where extrude is used on the top and bottom of the triangle. Can't work out how to only select the top edges (and bottom edges) to extrude as when I attempt to every edge gets selected.I think I am not doing something correctly when I separate - do I need to select edges before doing this as the video appears that is being done? – John Arnold Sep 23 '22 at 23:58
  • Sorry, I was probably rushing too much and didn't make it clear enough. All the other edges are separated from the object before with (P->S or Mesh menu->Separate->Selection) so only the top and bottom triangles remain. Since you want round rods at the corners and also square diagonal rods those should be separated from each other as well so you can have different curve bevel settings for each after converting them to curves. – Martynas Žiemys Sep 24 '22 at 08:09
  • Sorry my first time using extrude, the solidify modifier and bevel so a bit slow on the intake of all that. Have now created the 'bars' but only at the bottom of the model as I intend to stack each one on top of the other to create the total height of the mast. I am assuming that the diagonal bars are created using the same method as the 'bars' at the base. Lastly the mast I am trying to model is 'stepped' so that as the mast becomes higher the triangular sections are a bit smaller and I intended just to use Scale on a triangular section - see image just added to original question. – John Arnold Sep 24 '22 at 09:01