Pipe - making an 90deg Elbow

[Cunoblin]

hey all, I'm trying to make some pipe joints - i've made a Tee so far - that was easy.

 

but now i'm stuck making a 90deg elbow.

i have the 2 ends, hollowed.. but I can't seem to join them in a sweeping arc - the elbow part of it.. and no commands i am seeming to use are working.

 

any suggestions?

 

thanks

[L_Ruts]

Draw the centerline radius arc, then extrude the circle along the path of the arc.

 

Command: EXTRUDE

Current wire frame density: ISOLINES=4

Select objects to extrude:

Specify height of extrusion or [Direction/Path/Taper angle]: P

Select extrusion path or [Taper angle]:

[Cunoblin]

i tried drawing an arc.. but it won't let me in 3d space. i have both end pipes positioned.. and when I try to draw an arc, it stays 2d.

[L_Ruts]

The arc will be in 2D, you need to daw the arc and select it as the path for the extrusion of one of your circles. The arc should start at the center of 1 circle and end at the other. You dont need to select both circles, you can just use the second as a reference point for the endpoint of your arc.

[adirondackbell]

An alternative to the extrude command is the sweep command (beginning in 2007). Just sweep the circle along the arc path.

[L_Ruts]

An alternative to the extrude command is the sweep command (beginning in 2007). Just sweep the circle along the arc path.

 

The SWEEP command does not have a distinct advantage over EXTRUDE in this application, this is a simple 3D object, I am not speaking out against the SWEEP command by any means. You could also use LOFT along a path as well, but there are no reasons to use one over the other, whatever you're used to or more comfortable with.

[adirondackbell]

I completely agree, they all work fine.

[nialb]

I am no expert in 3D and really only started to dip my toe this week. I have attached one of my efforts that is probably an example of what you want to do.

 

Ignoring the handrail standards, the way I created the hollow bent tubing is as follows;

 

I created a 2D path using lines and an arc. I converted the lines to a polyline (Modify/Object/Polyline). In an isometric view I rotated the UCS and drew the outer diameter circle of the tube. I then drew the inner diameter. I extruded the inner and outer to 'path' (Draw/Solids/Path). Next I subtracted the inner from the outer to give a hollow pipe (Modify/Solids Editing/Subtract). Finally I deleted the path.

 

Well that is how I went about it but I'll bet there are loads of other ways.

 

Hope this helps.

 

Nial

3D Railing.dwg

[rkent]

Using Sweep means you don't have to draw the circle perp to the path and have the circle located properly on the path.

 

Unless you really need the pipe hollow for some reason there is no reason to go to the extra step. With sweep you can draw the two circles, make them regions, subtract, and use the region to sweep.

 

As you say, lot of ways to do the same thing.

[nialb]

Reading my reply above I thought I could make some points a bit clearer.

 

I drew the inner and outer tube diameters using the end of the polyline as the centre of the circles. I drew my polyline as a 2D line (top view and front view) and then positioned it in an isometric view in the centre of the handrail standards. You will notice that the standards are seperate from the railing as the railing passes through. I used the UCS toolbar fairly extensively to rotate the views using the x, y and z axis rotate tools.

 

[nialb]

Hi rkent.

 

The only reason I made the tube hollow is because I was playing Actually I was just using it as an excercise as I am teaching myself 3D modelling. I will try your approach as it sounds a bit simpler.

 

Regards

 

Nial

[JD Mather]

The SWEEP command does not have a distinct advantage over EXTRUDE in this application.

 

The Sweep command has a distinct advantage over Extrude in this application as you don't need to have the profile aligned with the path.

 

Simply create a "library" of region profiles you commonly use in your pipe runs.

 

Create the pipe run skeleton (of course arcs for bends are planar entities so you will need to learn the UCS command) and then Sweep. The Sweep will automatically align the center of the profile to the path - so the orientation of the profiles is irrelevant. Can lighting fast populate runs of different diameters. Far faster than could be done with Extrude.

 

http://home.pct.edu/~jmather/content/CAD238/AutoCAD%202007%20Tutorial%208.pdf

[nialb]

I am using 2005 and I don't think the Sweep command is available?

[JD Mather]

I am using 2005 and I don't think the Sweep command is available?

 

Nope, not avialable until r2007, the OP indicated he is using r2009.

[L_Ruts]

The Sweep command has a distinct advantage over Extrude in this application as you don't need to have the profile aligned with the path.

 

Simply create a "library" of region profiles you commonly use in your pipe runs.

 

Create the pipe run skeleton (of course arcs for bends are planar entities so you will need to learn the UCS command) and then Sweep. The Sweep will automatically align the center of the profile to the path - so the orientation of the profiles is irrelevant. Can lighting fast populate runs of different diameters. Far faster than could be done with Extrude.

 

http://home.pct.edu/~jmather/content/CAD238/AutoCAD%202007%20Tutorial%208.pdf

 

 

Not so much, if all you're drawing is 1 elbow, and you already have both end circles drawn, how is it harder to draw the arc from center to center and define the radius, rather than just in the middle of nowhere? I'm not saying that it doesnt work or extrude is better, but according to what he said, he already had both endpoints defined. Actually to draw the arc not along the center line path would be more work. You would have to draw reference objects to define the endpoints of the arc, or draw a circle and trim it from quad to quad, then sweep.

[Lee Mac]

This may help you with the 2D stuff

 

http://www.cadtutor.net/forum/showthread.php?t=32658

 

See last updated version.

[Bill Tillman]

I don't mean to sound too "simpleton" here, but the guys question referenced that he was having trouble getting the curve drawn in 2D for a 3D model. In my experience I find that getting the UCS set is the real key no matter which format you're working in.

 

I would just draw the use a curved polyline and then adjust the UCS accordingly, then draw a circle at one end of the polycurve and then EXTRUDE it along the path of the polycurve. Remember you can construct the elbow off to the side and then move or copy it into it's final position. I prefer to copy in case I need another elbow somewhere else.

 

The other command to help in this would be ROTATE3D. I've found that once I got these two under my belt along with SLICE and SOLIDEDIT I can do so much more than when I first started doing 3D modeling.

[Cunoblin]

alot for me to try out now.. and yes the pipe is hollow. I'm designing an aquaculture tank in full 3d.. and all the piping is of course hollow. i could just make it solid.. but hey i like detail

 

i'll try out all your suggestions and let you know if I get it working.

[Cunoblin]

YAY... thank you so much... i was so trying it the wrong way at first...

I made the arc and the circle... extruded it along the path..

made a 2nd one just slightly smaller and subtracted them to get the hollow pipe.. it's not perfect.. but it's working

 

 

thanks everyone.

[TimZilla]

I work in Fire Protection. We use a lot of Cast Iron threaded fittings and Grooved victaulic fittings. Let me know if any of this will help you and I can send you a lot of blocks.