3D Tubes

[Chris_Hebden]

Hi all, i was looking for some advice with drawing 3D tubes in AutoCAD. I am looking to draw an inlet manifold of a car and would like to draw the runners connecting to the plenum.

 

I have no idea where to start and have nothing really to show you to explain any better than the above unfortunately ! I have AutoCAD 2010 and have plaid with the torous function and trying to slice that into a shape i would like, but cant do that either !

 

Any help would be greatly received! This is a great website by the way!!!!

 

Chris

[ReMark]

You should change your profile to read AutoCAD 2010.

 

Do you even know how to create a straight tube section?

 

Do you have a diagram for the inlet manifold you want to draw?

 

This may actually be a job for Inventor or Solidworks.

Edited January 6, 2011 by ReMark

[ReMark]

Quick example. Start with two circles representing the I.D. and O.D. of your tube. Using the PressPull command click between the two circles (where you see the red "x") then move your mouse in the direction you want to go (up or down). Exact distances can be entered at the keyboard.

 

This is just one of three or four methods that can be used.

 

[ReMark]

You might want to check out this related thread.

 

http://www.cadtutor.net/forum/showthread.php?29321-Tube-exhaust-manifold&highlight=manifold

[JD Mather]

I would not even begin to try to create something like that in AutoCAD, unless you are going to keep it very simple. Use Sweep.

 

If you are a student I would download free Autodesk Inventor for this effort http://www.autodesk.com/edcommunity

 

This should get you started - if you can tie a knot.....

http://www.mcadforums.com/forums/viewtopic.php?f=5&t=11758

[ReMark]

An example using the Sweep command. The centerline of the tube is created and then a circle is "swept" along it.

 

 

A second, close-up, view. Some additional work was done to hollow the tube out.

 

[Jack_O'neill]

Back in the pre-Mechanical Desktop days I did that sort of stuff all the time for the refrigeration industry in AutoCAD 14 and 2000. It's not difficult once you get the hang of it. Remark gave you a good start. The key to doing that sort of thing in Autocad is to visualize how the tubing bender will make the bends in the tube. It will grasp the tube by one end, position the tube for the first bend. The dies will then grasp the tube and make the first bend. The dies will retract, the bender will feed the tube forward and rotate it to the position appropriate for the next bend, grasp and bend again. I know a text description of this doesn't make much sense and later today I'll post a Jing video of what I'm talking about. I have to make a run into the city this morning to meet a supplier so it will probably be around noon before I get it posted.

[ReMark]

I took a look at a bunch of inlet manifold images on Google and I really wouldn't want to attempt drawing one in AutoCAD if there was a better way.

 

JDM: What would be some of the advantages to doing this in Inventor? How might it be easier to do?

[JD Mather]

JDM: What would be some of the advantages to doing this in Inventor? How might it be easier to do?

 

Inventor allows you to project two 2D views onto each other resulting in the 3D path. So all you need is the top view and front view in 2D and Inventor will create the 3D path for you. I'll try to post another example (other than the knot) later today. I'm thinking this would be possible in AutoCAD with the xedges command, but it would be a lot more work to set up given the way that command works.

[ReMark]

The ability to project two 2D views onto each other sounds like it would be very useful. Thanks.

[SEANT]

In 2011, at least, the intersect command works with surfaces as well as Region/Solids. Two curves can be extruded from a Top and Side views, for instance, to create the necessary intersecting geometry. i.e., curve from two views.

SurfIntersect.dwg

[JD Mather]

That example looks good - result curve is continuous spline. (generating curves are splines)

Now what if the two surfaces are created from generating curves of polylines - say an arc and a line joined as polyline then extruded surface.

 

I don't have time to experiment right now - but the idea is to get a spline intersection as in your example, then Sweep circle for tube aligning to the spline.

[Chris_Hebden]

Wow, you guys move quick! Thank you very much! I can do 3D stuff, but i cant do 3D bends. Sweep sounds very interesting! Thats exactly how i wanted to do it! Draw the rough runner shape using a poly, and i thought that cad could extrude a circle along the shape of the poly, but from what i gather, swep does the same? Seant, could you briefly describe how you drew the attached file?

 

Many thanks people

[SEANT]

That example looks good - result curve is continuous spline. (generating curves are splines)

Now what if the two surfaces are created from generating curves of polylines - say an arc and a line joined as polyline then extruded surface.

 

I don't have time to experiment right now - but the idea is to get a spline intersection as in your example, then Sweep circle for tube aligning to the spline.

 

I don’t think that scenario is particularly easy with the “xedge” suggestion, either. But, to give the scenario some consideration with the “intersect” methodology, a splined recreation of a poly is not that difficult. See attached.

Sweep.zip

[SEANT]

Wow, you guys move quick! Thank you very much! I can do 3D stuff, but i cant do 3D bends. Sweep sounds very interesting! Thats exactly how i wanted to do it! Draw the rough runner shape using a poly, and i thought that cad could extrude a circle along the shape of the poly, but from what i gather, swep does the same? Seant, could you briefly describe how you drew the attached file?

 

Many thanks people

 

Essentially, I just created two splines in perpendicular planes. The extrude command will create surfaces that can then be processed with the INTERSECT command to create the 3d Geometry.

[Jack_O'neill]

No doubt there are much fancier ways to do this, and if you have Inventor or Solidworks it can probably do it much quicker. The method in this video is not difficult, but it is a bit time consuming and tedious. End product looks like this:

 

I apologize for the quality of the video. It's got some long hesitations and is a bit jerky, none of which was happening on the screen. This is the first time I've ever used Jing, so I may not have done something correctly. Hopefully you get the idea of whats going on:

 

http://screencast.com/t/6fL6XgzKWW1

 

The black circle is there just as a visual reference to the bending die for the tube. It really helps see how tubing is bent on an automatic tubing bender. I'd suggest searching Google for a video of a Chiyoda or Pine bender in action. Makes it much easier to visualize what you need to do to bend tubing.

 

--edit--

figured out what caused the problem with the video...my antivirus package doesn't like jing for some reason. Turned it off and made another and the problems went away.

Edited January 7, 2011 by Jack_O'neill
new info

[NAILER20]

Hi remark the concept of the tube is bares a striking resemblence to a problem I am haveing with cables I want to for a splined line that connects two misaligned terminals I tried to sweep my spline autocad 2011 mechnical just says n way

i've drawn 3d polylines to my connection points then ran a sweep got a non smooth entity and one end is never pointing in the right direction

thais is driving me nuts cause I've been doing more and more 3d work and this cable problem is my achilies heal

[ReMark]

Without the actual drawing I'm not sure I can advise you as to the best method nailer. Maybe someone else here can help. Sorry.

[Jack_O'neill]

Had some time this afternoon, and this discussion brought back some pleasant memories. Found myself playing around with bending tubes. Here's another using that same method (sorry, this is a bar, didn't put out the effort to make it hollow.

 

By mimicking the action of the bending machine on screen, you can create shapes that can be manufactured with common equipment in tubing shops. This particular example would be difficult on a standard Chiyoda or Pine bender, but with some special dies it could be done. If this were a real part, the machine operator would not have nice things to say about me.

[Jack_O'neill]

Hi remark the concept of the tube is bares a striking resemblence to a problem I am haveing with cables I want to for a splined line that connects two misaligned terminals I tried to sweep my spline autocad 2011 mechnical just says n way

i've drawn 3d polylines to my connection points then ran a sweep got a non smooth entity and one end is never pointing in the right direction

thais is driving me nuts cause I've been doing more and more 3d work and this cable problem is my achilies heal

 

Try increasing the value of the FACETRES variable, that might smooth out the dispay for you some. It defaults to 0.5, has a maximum of 10.

 

You mentioned that one end wasn't oriented correctly. Does that end look funny too, like a sort of wedge shape maybe? I found this to be the case when drawing wires that came out of plugs if I didn't have that last segment of the 3dpolyline exactly parallel to the body of the plug. In the pic below the yellow plug is rotated 90° and 1.25 inches above the green plug. The wire between them was created by simply clicking here and there to create the appearance of a random piece of wire that no one had tidied up.