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Autocad 2014: How To Draw Steel Square Tubing?

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autocad2014newbie

I'm new to AutoCad. I'm trying to figure out a simple way to draw steel tubing which is basically a tubular square with a hollowed out middle, but the sides of the tube all have a certain thickness to it. I'm able to draw the initial square with the fillets on the corners, and hollowed out middle, but cannot find a way to properly resize it to the appropriate length I want to use for my design once I draw it and go to extrude it. Is there a tutorial or video that shows how to create something like this?

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ReMark

You can use either the PressPull or Extrude commands and type in a length at the command line.

Edited by ReMark

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Dadgad

Welcome to CADTutor. :)

 

Did you use the OFFSET command to define the wall thickness?

Best way to do it, draw either the inside or outside shape, then use OFFSET to

replicate it, taking into account the appropriate wall thickness.

 

http://www.cadtutor.net/tutorials/autocad/index.php?category_id=25

 

That link will take you to the Tutorials on this forum dealing with basic 3D Modeling techniques.

They would probably all help you, when you have time to go through them. For this particular task, choose the Extrude & PressPull one.

 

Or, as ReMark suggested, just give them a go. Read the commandline prompts

and you should be good to go. PressPull is the more intuitive of the two commands.

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ReMark

3D Sq Tube 1.PNG

An example of a 3D square tube. The profile is to the left.

 

This 6" high 5x5x.375 tube shape was created with the PressPull command. I could have also used the Extrude command.

 

I'd recommend building a library of often used shapes using the Region command to subtract the inner profile from the outer profile then save as a block. Insert, explode then PushPull to the desired height.

Edited by ReMark

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ReMark

3D Steel Shapes.jpg

Examples of other steel shapes in 3D. Each shape is a block. In the image above you'll find a C5x9, L4x3x0.25 and a W6x15.

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autocad2014newbie

Oh WOW! Seeing your 3D models of structural steel got me so excited for what I want to do with my projects! :shock:

 

I took both of y'alls advice, but every time I use the 'extrude' command, it pulls the entire top off, ignoring the hollowed out center. I had some success with the 'presspull' command, even though the strobe flashing of the object trips me out a bit and having to delete the hollowed out flat surface at the bottom. I will be using 'presspull' for now, but am wondering what I am doing wrong when trying it with the extrude command.

 

I hope I'm not asking for too much, but can you analyze the steps I'm taking and point out if I'm doing anything wrong or adopting bad autocad practices as I go along? I learned these steps by watching a couple of different autocad videos and mix-n-matching what I learned from them all together.

 

These are my steps (skipping the fillet part for now):

1.) Select Polyline, click on a horizontal plane, move mouse horizontal right, type [1], enter, move mouse vertical up, type [1], enter, move mouse horizontal left, type [1], enter, move mouse vertical down to first point, type [c].

 

2.) Select Offset, click once at midpoint of the top horizontal line, press enter (am i supposed to click to a certain direction after clicking on the midpoint or is midpoint click and enter fine?), click top horizontal line again to begin extrude, move mouse down to [1/8"], press enter.

 

3.) Type, Region, select outside square line, select inside square line, press enter.

 

4.) Type, Subtract, select outside square line, select inside square line, press enter.

 

*This is the part that normally works when I use the PressPull command, nevermind the trippy automatically drawn animation before I even select my surface, when I use the extrude command, it ignores the inner square and pulls it up together to form a flat surface again with no extruded surface.

 

*5.) Select Extrude, click outside square surface, pulling up or type length number, press enter. Entire square tube is lengthened, but top surface is flat again with no more offset top.

 

Are these the same steps you guys take when doing what I'm trying to do or do you do anything different in the same pursuit? And why does it work correctly when using PressPull, but not Extrude?

Edited by autocad2014newbie
*Corrected step 2 from saying Extrude to Offset

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ReMark

After creating your regions then subtracting the inner square from the outer square are you left with just one object? If not then you have done something wrong.

 

If you have done everything right it should not matter if you use Extrude or PressPull the result should be the same.

 

Attach a copy of the drawing to your next post.

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autocad2014newbie

Using visual style x-ray, hoping this would be the most helpful to convey what's going on not sure which one you would of preferred. (not sure why the second pic came out doubled).

 

Subtracted:

subtractd.jpg

 

Extruded to [1]:

extruded.jpg

Edited by autocad2014newbie
accidental doubled screenshot

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ReMark

Please attach a copy of the drawing to your next post.

 

I have a suspicion of what might be happening but I need to physically exam your drawing.

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autocad2014newbie

It's drawn inside another project I was practicing with from YouTube.

 

Project:

desk_drawing.zip

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ReMark

It appears your use of the Region and Subtract commands failed to produced the required results. No matter. Extrude the inner square then subtract from the outer square to get the final hollow tube.

 

Why do you have Thickness set to 4'-2"?

 

Are you aware that if you subtract the cylinders from the legs of the desk the holes will not pass entirely through the legs?

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autocad2014newbie

Sorry, I kept refreshing waiting for a reply and didn't see that there was a second page.

 

Hmm, I can't seem to get anywhere by extruding the inner square, then subtracting. Nothing seems to happen. Does it matter in which order I subtract each square in the beginning? Like should I first select the inner, then outer square, or outer then inner?

 

Thickness was just a random number for the time being until I can figure out what I'm doing wrong with my Region/Subtraction steps. Once I get that down I can focus on replicating the steel structure models to pinpoint accuracy.

 

What do you mean they won't pass entirely through? @the desk table, that part of the tutorial was creating an array of cylinders, exploding them, then subtracting them from the leg to create a hole in each leg, but I believe I only ended up selecting the 1st hole instead of all of them which is why only one leg has a proper cylendrical hole through each leg before I mirrored them. Here's a link to the tutorial I followed for the drawing. https://www.youtube.com/watch?v=n8i1-DUirik

Edited by autocad2014newbie

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ReMark

Pay attention to what AutoCAD is asking you to do when using the Subtract command. You pick the object that you want to subtract FROM first. Then you pick the object to subtract second.

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autocad2014newbie

Hmm, then I am using the subtract command correctly. Question, when drawing a square from top view in autocad, let's say you were to pan the view, does the square you just drew have some height on it? I'm not sure if this is normal, but everytime I draw a square in the beginning, I pan the view and the square is not just a plain square with 0 height, it's about 4ft. long up. I'm thinking this might have something to do with my problem. Is this normal?

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ReMark

That is not normal and the reason you are seeing that is because you have THICKNESS set to 4'-2". Set it to "0".

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autocad2014newbie

Ah ok I see. That seemed to solved that problem. I guess I'll keep experimenting with the Region and Subtract commands until I figure out why they're not functioning as they should. At least I can use PushPull for now. There's tutorials on just about everything on YouTube except structural steel =[. I had been stuck for hours trying to figure the square tube thing, and now I can move on to the design phase thanks to you and dadgad's help. One last small off-topic question, you adviced me build a library of these objects for further and easier use in the future. How would I go upon saving one of the models as an object?

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ReMark

You save the profiles of your tube shapes as a block. You are familiar with the BLOCK command aren't you?

 

FYI - Blocks cannot be extruded. They have to be exploded first.

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autocad2014newbie

I am not familiar with the block command. This is my 1st day with autocad. I'm learning the basic commands as I go from watching YouTube videos and googling their definitions and syntax. I'll look into 'explode' after I figure out my region/subtraction problem as I don't want it to cause problems later down the road and I'm not sure if I'm breaking forum rules by going off-topic from the original question/topic.

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ReMark

Appears as though you have some studying to do re: BLOCK command then.

 

The Region and Subtract commands are covered in your AutoCAD Help file. Read up on each.

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autocad2014newbie

Will do. Thank you so much for your help once again. I'll come back and post in the thread if I am ever able to figure out what was causing my Region/Subtraction problem.

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