View Full Version : How to draw if I can't join plines?
21st Apr 2008, 05:24 am
I'm trying to draw the object below and have run into a problem. I drew circles on top of the base and now I want to draw plines so I can extrude these circles along a path to get the tubes from the picture. Since these lines must be drawn in 3d I was drawing them in front and right ucs but then I can't join them because they are not coplanar. I feel really stupid and I just can't figure out how to draw this!! I'm using Autocad 2008.
If anyone has any suggestions I would love to hear them!
21st Apr 2008, 07:44 am
u need to us 3DPOLY not pline, just draw over the old lines using 3dpoly
21st Apr 2008, 01:58 pm
To make your 3D Poly line have curves simply click on the Polyline then, in properties (under fit/smooth), select cubic. If you need the pipe run to have "tighter"/smaller radii then select quadratic (but bear in mind that quadratic uses a LOT more memory so in large drawings it is best to be avoided.
If you have a choice between using sweep and extrude then I recommend going for the extrude option because the resulting run will again be less memory intensive.
3D AutoCAD Pipework – http://www.HerculeDesign.com (http://www.herculedesign.com/)
21st Apr 2008, 03:37 pm
Thanks for your replies.
I tried drawing over the lines I had with 3dpoly and everything looks fine in a SE iso view but not from a front or right view. Also it wouldn't let me extrude along this path. What ucs should I be using to draw this 3dpoly line?
21st Apr 2008, 03:46 pm
You might need to adjust your ucs as you're drawing it. Not sure if you can do that while in the 3dpoly command. Can someone confirm?
21st Apr 2008, 04:06 pm
This is what I wanted to do originally but I'm unable to change the ucs in 2d polyline (it is greyed out after I start the pline command) - same thing with the 3dpoly command.
21st Apr 2008, 04:09 pm
Maybe you could just type in coords?
21st Apr 2008, 04:15 pm
I had to try it, but the only way I could get it to be 1 solid was to extrude a circle along each path (line or arc) and then join them to get to 1 entity.... it would be tedious to do all of them that way, there is probably a better way......
21st Apr 2008, 04:35 pm
I can handle tedious as long as it works.....how did you get the filleted corners? I mean the fillet between the front ucs pline and right ucs pline before joining them.
21st Apr 2008, 04:49 pm
Started with just lines, and fillet to a radius. The tedious part is copying the circle to 1 end of each entity and extruding each seperatly, That's why I think there has to be a better way.
21st Apr 2008, 05:11 pm
...The tedious part is copying the circle to 1 end of each entity and extruding each seperatly, That's why I think there has to be a better way.
There is. No need to copy the circle anywhere with Sweep.
Just do the Sweeps and Union. Done. Make sure to set delobj = 0 and the circle will automatically be aligned with each path by AutoCAD.
(the delobj variable is set to 0 so that you can use the profile over and over as many times as needed - then tap away at the spacebar once started, follow the command line prompts)
21st Apr 2008, 05:38 pm
I still don't understand when you are filleting......I can't fillet non coplanar lines and I can't fillet the object after it is joined.
21st Apr 2008, 06:30 pm
Ohh OK, Sweep with the alignment is the way to go, I had to re-read your post JD, but the delobj= 0 is the way to go....
Morality, I couldn't fillet your lines either, I had to erase and redraw 2 of them to get the fillet to work on all angles. these 2 must be off UCS or whatever you call it, must not be aligned.. JD response has the solution though.. VERY COOL, thanks JD!!
21st Apr 2008, 06:56 pm
I can't fillet the object after it is joined.
If the UCS is correct you should be able to fillet a 2d polyline. But I wouldn't even fool with polylines. Draw the lines and change UCS as needed to fillet.
21st Apr 2008, 07:23 pm
Thanks guys....I will try the sweep just as soon as I figure these lines out. I feel like such an idiot. So ghostrider....i noticed in your drawing that all the lines were in the right ucs but when I tried that it ended up looking like this (see file - note that in the right view the lines are not where I want them at all, but in se iso it looks fine).
I'm not sure what you mean by "Draw the lines and change UCS as needed to fillet." I was changing the ucs as needed but then because the lines aren't all drawn in the same ucs it is impossible to fillet them because they are not coplanar.
21st Apr 2008, 07:49 pm
I feel like such an idiot.
Don't let yourself think this way. It does you no good.
21st Apr 2008, 08:21 pm
...when I tried that it ended up looking like this (see file - note that in the right view the lines are not where I want them at all, but in se iso it looks fine).
... I was changing the ucs as needed but then because the lines aren't all drawn in the same ucs it is impossible to fillet....
You should not need to change the UCS to draw the lines. Forget about the fillets for now. With Polar Tracking on you should be able to track along x, y or z axis and use direct distance entry. Get the lines and then post the file and I will show you how to add the fillets.
21st Apr 2008, 08:38 pm
hmm....maybe my problem is that I don't know how to track along the z-axis which is why I was switching between front and right ucs in order to get the correct elevation.
21st Apr 2008, 09:00 pm
hmm....maybe my problem is that I don't know how to track along the z-axis
In 2008 the cursor now shows x, y and z tracking. You just need to figure out the distances you want to go.
21st Apr 2008, 09:14 pm
argh.....I just figured out I've been trying to draw in 2d wireframe.
Okay, so that didn't solve my problem. When I track the x or y axis the coordinates in the bottom left move to indicate I'm tracking that axis. But no matter what ucs I use when I tray and track the z axis all that happens is both the x and y coordinates are changing and the z coordinate remains constant.
When I try drawing the lines from your demo.....at the point where your dyn says -Z mine says 315 degrees....then yours says polar 0 degrees and mine says polar 225 degrees. Is there some polar or tracking setting i need to be changing?
22nd Apr 2008, 09:07 pm
Hi JD....I'm hoping you can help. No matter what I do my autocad will not track along the z-axis. The dyn never changes to say +Z or -Z. I can see that what I am trying to draw would be much easier if this were the case because I am always getting the error message "lines are not coplanar" when trying to fillet. The last pair I checked even had the exact same endpoints and still they were non coplanar.
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