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Dimensions in 3D drawing placed on one plane


xjessie007

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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

dimensions.jpg

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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?

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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

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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

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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

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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.

dimensions4.jpg

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

 

"You should be reorienting the UCS to the plane you are dimensioning" ... is it possible to set up cad in a way that this is happening automatically? When I change the angle of view, so that the UCS would adjust accordingly?

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You could try using the Dynamic UCS. It is supposed to make working in different planes easier. Personally, I turn the feature off because I couldn't get used to it. You may find it easier to work with.

 

You are doing all your dimensioning in model space aren't you?

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Yes, in model space.

I have dynamic UCS on, but it does not seem to be working. But I think I will be able to get used to manual UCS. After spending the whole day doing it manually, I think it will be ok. Still bothering my mind, what change could have caused the change in behavior of my cad. :|

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  • 1 year later...

Well, it's been two years since this went up, but maybe it will help someone else who's searching for an answer.

 

In Autocad 3D drafting, the UCS is initially at 0,0,0 with Y up, X to the right and Z straight at you. Yours is at the top of the roof. I'll bet you started drawing with the front face of the house first, right? Dimensions always appear at the plane where the UCS is located when you make the dimension. If you draw something starting 20 ft off the "ground" (zero Z axis) and dimension it, the point will be at a Z of 20' and the dimension lines and text will be at zero. To have the dimensions tied tight to the object, you have to set the UCS origin at 20' high. Now 20' will show as zero feet high, it becomes your new basepoint.

 

I use manual UCS and use the UCS toolbar to locate and rotate the UCS to draw in particular place and direction. You can align the UCS to an object, a surface or the view. If the Z is showing on the UCS, rotate about the other axis that shows (X or Y) and it will make Z come straight out at you, or away from you. Now you can draw in the way you're used to.

 

I'd put your UCS on the bottom left corner of the house with Z up and Y to the back of the house and X to the right. Now those dimensions will lay flat on the ground and tight to the house. To dimension the left side of the house, rotate the UCS 90 degrees around the Z axis, then 90 degrees around the Y axis, so Z is pointed at you, X is up to the roof and Y points to the left. Now the text will run up the left side of the house. The text will always run in the X axis. If X points to the left the letters will be backwards. If the Y points down, the text will be upside down.

 

Good Luck!

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Yes, in model space.

I have dynamic UCS on, but it does not seem to be working. But I think I will be able to get used to manual UCS. After spending the whole day doing it manually, I think it will be ok. Still bothering my mind, what change could have caused the change in behavior of my cad. :|

 

I suspect that your OBJECT SNAP OPTIONS have been changed, and should be set as shown in the image. You might also want to use your VIEWPORT CONTROLS in the upper left hand corner of any viewport, or your VIEW toolbar to navigate your perspective changes, as it works like you have your UCSFOLLOW variable set to 1, makes it easier to work without having to pay much attention to your UCS on the fly.

restore your object snaop options.JPG

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