# Thread: Dimensions in 3D drawing placed on one plane

1. ## Dimensions in 3D drawing placed on one plane

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Hi,
I would like to ask a question about dimensions in 3D drawing being placed on one plane. I have a 3D drawing, and when I draw a dimension, it gets placed by the program on the XY plane. The dimensions do not stay along the dimensioned objects. Please, see the attached picture. For example, you draw a line from [1,1,1] to [3,3,3] and then dimension it. The dim line is placed to [1,1,0]-[3,3,0] instead of along the line. Would anyone, please, know why this is happening? Thanks.
JT

2. Maybe you should try relocating the origin of your UCS.

3. I am not sure what exactly you mean. Can you explain, pls? Tx.

PS: I think it has something to do with system variables because even if I open a new or old drawing, dimensioning works as described in all drawings. Even if I open old drawing with dims in all planes placed correctly, then when I add new dimensions, the new ones get placed on the one plane as described. Which system variables relate to dimensions and how do I access them?

4. I have created another sample drawing from a scratch. Please, see the attachment. Weird thing. I am lost.

5. Use the 3 Point UCS. I use it a lot and it's the fastest way to get the ucs where you want it.

3pucs.png

Pay close attention to your X axis or your dims may be upside down.

KC

6. Originally Posted by kencaz
Use the 3 Point UCS
What do you mean by "3 Point UCS", please?
Thanks.

7. With few exceptions in AuotCAD what you draw is drawn on an imaginary plane in the model space of your drawing.

The UCS is the means to move that plane around in model space. The plane is on the X-Y axis and the Z axis comes "up" out of the plane. When you want something to show up in a particular place, you need to either use snaps to snap to a different elevation above the plane, or move the plane to the place that you want the thing (in this case a dimension) to be.

Just realized its late, I got Daddy duty, if you have more questions, just post.

How long have you been using AutoCAD?

Glen

8. Originally Posted by xjessie007
What do you mean by "3 Point UCS", please?
Thanks.
Command: UCS

The default selection is 3 point.

First point set origin,
Second point positive X
Third point positive Y

USC F1 will clarify better.

KC

9. Hi,

Thanks for your reply. I am starting to get the idea. I am playing with this thing around now, and I am able to move the UCS to a given point and adjust its direction too to draw the dimension in the correct place, see the attachment. But, it looks like I have a problem with snaps too, they do not snap to objects at the plane I expect to. For example, I draw a line, it snaps correctly on the X and Y planes, but totally wrong on the Y plane (I have all options turned on in the snaps settings screen). Or, sometimes, it does not snap at all when I hover with the UCS over the object. It is starting to appear to me, that I might have some problem with the dynamic UCS? I have the dynamic UCS enabled in the task bar, but maybe I need to check some other setting somewhere else too?

In other words, when you look at the attached picture, the UCS is at the corner of the object. When I rotate the object, it does not move or adjust in any way even though I have dynamic UCS enabled. Could that indicate anything?

"you need to either use snaps to snap to a different elevation above the plane" ... I think this is the piece that does not work for me correctly for some reason.

Thanks.

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You should not be rotating the object. You should be reorienting the UCS to the plane you are dimensioning.

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