3D polyline help...

[Yafim]

Hi, don't know if this is the place but help would be very..um..helpful

 

I'm trying to create (in 3D workspace), a 3D polyline which starts from the "ground" and goes up the Z axis for 45 units (meters for example), then, the polyline continues "up" but in a 45 degree inclination, and then it goes up further but still 45 degrees from the last segment.

I attached a picture of this to the post, the top line is the one I want to create, and the bottom one is what I get.

The thing is that the 3dpoly command doesn't let me set the line on the Z plane, unless I fix it in ortho mode, and even after I do the first segment that way, the next one stays fixed in either the Z plane or the XY plane, but not in the 45 degree between them that I want....

 

Sorry for the long post, but this is really simple and I can't seem to do it. I hope you can help.

 

P.S. - when I click the 3d polyline command, there are no options in the command area, just "specify first point...." - is this what should appear? no options?

 

Thank you!

[ReMark]

Maybe it's just a matter of viewing it from a different angle?

 

I was able to do it using a 3Dpoly and all keyboard input for distance and angle.

 

How do you have your UCS oriented?

Edited June 14, 2011 by ReMark

[Yafim]

Thanks for the quick reply.

 

About the USC, i don't really know how to use it That well... what do I do to set it so that it will help me draw the 3d plolyline?

 

And - if you managed to do it with keyboard inputs, can you tell me the order of your actions so that I can imitate it and see what the problem is?

 

again, thank you

[qball]

Keyboard inputs as mentioned would look something like this:

[ Specify start point of polyline: 0,0,10

Specify endpoint of line or [undo]: 45

Specify endpoint of line or [undo]: @45,0,45

Specify endpoint of line or [Close/Undo]: @45,0

Specify endpoint of line or [Close/Undo]: *Cancel*]

[Jack_O'neill]

If all else fails, you could draw the line you want in the current x/y directions just as you would a 2d drawing, then use 'rotate3d' to stand it up, then again to orient it in whatever direction you needed.

[ReMark]

AutoCAD 2010 I see. The UCS can be reoriented using the Dynamic UCS button (which some people find annoying), from the Home tab > Coordinates panel or via the keyboard.

[ReMark]

An example of my inputs start-to-finish.

 

Command: _rectang

Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]:

Specify other corner point or [Area/Dimensions/Rotation]: d

 

Specify length for rectangles : 12

 

Specify width for rectangles : 12

 

Specify other corner point or [Area/Dimensions/Rotation]:

Command: UCS

 

Current ucs name: *WORLD*

Specify origin of UCS or [Face/NAmed/OBject/Previous/View/World/X/Y/Z/ZAxis]

: x

 

Specify rotation angle about X axis : 90

 

Command: _pline

Specify start point: m2p

First point of mid: Second point of mid:

Current line-width is 0.0000

Specify next point or [Arc/Halfwidth/Length/Undo/Width]: @15.0

 

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: @22.0

 

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: @12.0

 

The result:

 

 

Viewed from this angle (SE isometric) it's somewhat difficult to determine what angle the middle segement is drawn at.

[ReMark]

Viewed from the front it is now apparent which way the lines are going.

 

[Tyke]

Another possibility if you already have all of your 3D coordinates is to input the points as AutoCAD 3D-points one at a time and then in an isometric view join the points with a 3D polyline.

 

Or draw a 3D polyline with the number of vertices you require, then in the properties window edit the coordinates of each vertex.

 

There are many ways of achieving what you want to do, just pick out the one that you find the best.

[Yafim]

Hi.

Thanks for showing in such detail.

I still didn't get it quite right...

A few issues:

 

1) I don't know about the m2p command, what does it mean exactly?

2) what do you set for the first and second points? you just click somewhere? i didn't understand what you did there...

 

3) Setting the UCS on the X axis... what did that do? what does that achieve to help create the pline?

 

Thank you very much.

I know these are simple things but i'm trying hard as a total beginner.

[Yafim]

And another thing I forgot:

 

The lines are supposed to be 45 degrees from each other each time, not in absolute terms.. that is the third line isn't parallel to the X, it's in an angle of 45 from where the 2nd line ended, which is in turn 45 degrees from where the first line ended.. or maybe i'm wrong and it has to come out parallel to X...

[ReMark]

M2P or MTP (either is correct) is a command modifier. It is used to find the centerpoint between two picked points. Use it after invoking the line command, for example, when prompted for a starting point. In my example I picked the midpoint of two opposite sides of my box.

 

Reorienting the UCS allows the user to draw in different planes.

[ReMark]

And another thing I forgot:

 

The lines are supposed to be 45 degrees from each other each time, not in absolute terms.. that is the third line isn't parallel to the X, it's in an angle of 45 from where the 2nd line ended, which is in turn 45 degrees from where the first line ended.. or maybe i'm wrong and it has to come out parallel to X...

 

So now you are changing the criteria?

[Yafim]

Great explanation on the m2p, now i get it

 

but - about the UCS, but making it on the X plane and setting it that way, does that allow you to create the polyline better than working in the World UCS?

(btw - the pline I looked for is 3Dpline and in your commands it's _pline.. isn't that a 2D pline? spline that is?)

 

Thank you again for you help.

[Yafim]

You are correct btw.. it does come out the way you constructed it with the 3rd line on a parallel to x... because it's 45deg + 45deg it has to..

 

sorry for the confusion.

[Yafim]

Can you show steps to create this in 3Dpline command? you showed it in the early post for _pline which is a regular pline.. that is why I think I can't imitate it..

[ReMark]

It doesn't matter if you use a regular polyline or a 3Dpolyline.

 

Command: _rectang

Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]:

Specify other corner point or [Area/Dimensions/Rotation]: d

Specify length for rectangles : 12

Specify width for rectangles : 12

Specify other corner point or [Area/Dimensions/Rotation]:

 

Command: ucs

Current ucs name: *WORLD*

Specify origin of UCS or [Face/NAmed/OBject/Previous/View/World/X/Y/Z/ZAxis]

: x

Specify rotation angle about X axis : 90

 

Command: 3DPOLY

Specify start point of polyline: m2p

First point of mid: Second point of mid:

Specify endpoint of line or [undo]: @15.5

Specify endpoint of line or [undo]: @18.73

Specify endpoint of line or [Close/Undo]: @9.77

[Yafim]

Tried it.

Did it.

 

Came out great. Thank you very very much I learned something here

 

If I understand correctly, the "@" command creates the next line in a relative coordinates from the end of the last line, in reference to it? right?

 

Thank you again ReMark

[ReMark]

The "@" symbol is a throwback to earlier versions of AutoCAD. I don't think it is even required any more. Force of habit for me to continue to type it in.

 

You're entirely welcomed Yafim.

[qball]

I think you still need @ if you have Dynamic Input turned off.