Trouble with Union..

Help! I've only recently come back to using AutoCAD and might be missing something simple, but I have spent hours on this problem and now need serious help.

I am trying to construct a 3D solid, part of which looks a bit like the front half or nose of an airship. This is made up of 19 segments (think of an orange) - I have tried to construct the "nose" by repeating the segment and then using the UNION command to make a single solid object. All went well to begin with then I started to get error messages such as "Inconsistent face-body relationships" or "Inconsistent containment of intersection curve". I thought that it might be to do with there not being total contact between faces so I extruded the bottom face of the original segment a small amount so that there would be guaranteed overlap. I tried COPYing the segment and then rotating it into place; I tried ALIGNing each new segment and finally I tried 3D ARRAY. In each case UNION sometimes worked but I have not been able to fathom out why and when. The most successful was when I used ARRAY and in the "finished" item I managed to get a block of 6 segments successfully UNIONed , another of 5, a 4 and then a couple of pairs, all adding up to the required 19, BUT I cannot get them all joined together!!! The error message in this case is "Inconsistent edge-face relationships." Can anyone put me right on where I am going wrong? Incidentally I do need the 19 facets on the model so revolving is not an option for me. Furthermore, when I managed to get 3 or four segments UNIONed I tried using that block as the building block for the "nose" , rather than the individual segment, but to no avail.

Extra: I have now attached a file with the original segment shown in the top left and the (almost) finished model in the top right of the page.

Thanks, Derek

3D Drg 2 failed Union examples.dwg

Download file.

Right click on filename and Extract all.

In AutoCAD - issue the acisin command and select the Unioned Nose.sat file

Unioned Nose.zip

Does the file, unioned nose.zip, include an explanation on how to do it in AutoCAD?

Does the file, unioned nose.zip, include an explanation on how to do it in AutoCAD?

No. I used a modern MCAD program. Might also try FREE Inventor Fusion http://labs.autodesk.com (I don't know how to use that program - so didn't try it.)

The OP is using AutoCAD 2004. I have the feeling he is not going to run right out and buy Inventor 2013. I thought it might be useful to him if you explained how he might accomplish the same result using an out-dated and less-than-modern CAD program.

I have the feeling he is not going to run right out and buy Inventor 2013...

Inventor Fusion 2013 is free. I would not even bother in AutoCAD 2004.

If the OP has an internet connection - won't need to run anywhere. Simply download http://labs.autodesk.com

Derek: Any chance you are going to download "free" Inventor Fusion 2013 and learn how to do this on your own or would you rather know how to do it in AutoCAD 2004?

Wow! Thank you so much J.D. and thank you for your concern ReMark. I would like to know how to do it in AC 2004 but I am going to download Inventor Fusion and see what road that takes me down. I will be back to let you know how I get on but, as someone else once said, "I might be gone for some time..." Hopefully not too long though; Thanks gain for the immediate fix, I really appreciate it.

OK , back sooner than I thought. There does appear to be a free Trial version of Inventor Fusion but the link would not work (possibly due to my geo-location or even speed of connection - I am in the mountains) but I'm afraid the full version - and it does look fantastic- will not be an option for me (unless I get my current project off the ground!) So, thanks again for the corrected solid J.D. , but if anyone knows what I was actually doing wrong in AutoCAD 2004 it would be a great help?

I no longer have access to AutoCAD 2004 to test if this performs any better but try to Union these solids. I modified the profile geometry a bit. With 3D Solids Boolean operations, AutoCAD may work more efficiently with Spline geometry instead of multiple arcs.

ModifiedProfile.dwg

Do not confuse Inventor Fusion

http://labs.autodesk.com/technologies/fusion

with Autodesk Inventor. Autodesk Inventor would be the better choice - but it is not free.

They are two completely different programs.

Inventor Fusion is full version (of what it is). They regularly post Technology Previews on labs.

Thanks Seant - I am really beginning to see just how out of date I am in using AC 2004! Unfortunately using UNION I managed to join four of the segments on ModifiedProfile.dwg but on the fifth, I once again got the "inconsistent containment of intersection curve " error message. I tried going in the opposite direction (using UNION anti-clockwise instead of clockwise in the xy plane) and I got "span info missing for ef-int construction" and that was a new one on me!! Interestingly I originally used SPLINE to construct the segment but could not find how to join line objects and spline objects to make a single object that I could then make into a 3D-solid, PEdit will not let me join the spline. So I traced over the original spline as closely as I could with a polyline and then proceeded from there. What command did you use to join the spline and the straight lines to get to the segment? Thanks for taking the trouble to try and help me.

I thought one could join a spline and a polyline or line using the PEdit command > Join option?

No, you can select the spline as if to JOIN it but on pushing Enter, all one gets is "0 segments added to polyline"

The REGION command will join Splines to the other, more common Lines/Curves. See the magenta object in my previous file.

Later versions of AutoCAD can Union all of those sections, though the command will take several seconds.

If it helps the project at all, here is the Solid.

Solid.dwg

That's at least part of the problem solved, thanks again Seant. REGION worked for splines and lines in AC2004. It looks like I have hit a real limitation of '2004 but it is still an enjoyable challenge trying to use it .... and anyway, needs must.

I had another go at locating the Inventor Fusion download and now have successfully loaded it. This time I used a link on the http://www.wired.com site in an article headed "5 Reasons to Download Autodesk Inventor Fusion Now" (previously I had got nowhere via the menus on Autodesk's own site.) It is onelarge download and is going to take me some serious study!!! I will not forget to come back and report how I get on but, in the meantime, thanks to JD Mather for pointing me this way.

The link posted by JD Mather (post #11) goes directly to the page to download.

Sorry JD, perhaps I was just having a bad day when I first tried that link ( or maybe the site wasn't behaving!)

....This time I used a link on the http://www.wired.com site in an article headed "5 Reasons to Download Autodesk Inventor Fusion Now"

Interesting on that site how much uniformed discussion can go on as though the writers know what they are talking about. Clueless. Even Kevin pipes in, but doesn't correct any of the uniformed statements.