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# Another Isometric Dimensioning Question

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05-07-2009 01:56 PM
All,

How do you dimension in 3D? I have no problem drawing dimensions on the X-Y plane, but all dimensions measured in the Z direction appear on the X-Y plane. I have searched everywhere for an answer and found nothing, could you please help me? Thank you.
*George Drayton
Message 2 of 6 (569 Views)

# Re: Another Isometric Dimensioning Question

05-07-2009 04:58 PM in reply to: joedvo
If I understand you, you change UCS orientation to suit your needs. The
dimensioning commandplaces the dimension in the current XY plane. You
may also want to investigate the FLATSHOT command which creates some 2D
geometry of the 3D view.

George Drayton CD-CAD Ltd Christchurch New Zealand
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Message 3 of 6 (569 Views)

# Re: Another Isometric Dimensioning Question

05-08-2009 07:08 AM in reply to: joedvo
I tried the flatshot command and I found that this command only works on 3D objects, I am working in 3D space, but not with 3D objects, so flatshot did not work. It is a useful command that I didn't know about, so thank you anyways! Let me try to explain in more detail.

Here is an example, picture a simple isometric drawing where a pipe that starts at the origin called point 1, travels in the X direction for 10 feet to point 2, this is pipe section A. At point 2 the pipe changes to the Z direction for 5 feet to point 3, pipe section B, and then travels 8 feet in the Y direction to point 4, pipe section C. I am able to put a dimension on the piping in pipe section A. But when I try to add a dimension to pipe sections B or C, the dimension appears on the plane where pipe section A is. When dimensioning pipe section B in the Z direction, the dimension will be a tiny number probably the width of the line itself. Each time I do this, I use the linear dimension tool with my object snap on "End Points", I click on one end and then the other and try to pull the dimension line out, and it appears on the X-Y plane.

I have also attached a screenshot of my iso. You will see that I am using 2D blocks to show how the pipe would be routed to the valves and steam traps. I chose to use the 3D space so that I could give multiple perspectives of this modification. I used the dimension tool on three pipes that I have colored green so you can associate them to the dimension easier. You will see that all dimensions are on the X-Y plane, the same as the origin. Please let me know if you know how to fix this problem thank you!
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Message 4 of 6 (569 Views)

# Re: Another Isometric Dimensioning Question

05-08-2009 08:51 AM in reply to: joedvo
If I understand you correctly, one of the previous posts indicated what you need to do. Change the UCS before you place the dimension.

I'll repeat what I think you described. You're using 2D symbols for valves, exchangers, etc. but you're routing the line in 3D. Is that correct?

I attached an example of what I think you're looking for. The 2'-0" vertical dimension?
Let me know. I'll check back later.
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Message 5 of 6 (569 Views)

# Re: Another Isometric Dimensioning Question

05-08-2009 09:23 AM in reply to: joedvo
I am not sure what you mean by changing the UCS. What you repeated is correct. In addition to the 2'-0" dimension, all of the dimensions above the bottom plane like 26'-9 5/8", 4'-2 1/4", and 7'-0". I cannot create a dimension for anything above the bottom plane where the origin is. What is the title of the previous post so I can check it out? Thank you again.
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Message 6 of 6 (569 Views)

# Re: Another Isometric Dimensioning Question

05-08-2009 10:20 AM in reply to: joedvo
George's post is the one I was referring to.

If you're going to work in 3D, you really need to read up on the User Coordinate System (UCS). Its absolutely essential you know how to manipulate the UCS to be able to do much of any 3D work efficiently. Learning 3D is not that difficult if you know how to set up views and use the UCS. 3DOrbit helps to visualize what you're drawing. Its much easier than it used to be. Acad Help will give you enough to get started. (use the UCS II toolbar and the View toolbar as a starting place to get familiar ... and of course 3DOrbit ... and when you're changing the UCS, watch the UCSICON change which is how you can tell if you have the ucs you're looking for ... front, back, top, bottom, right, left, and of coure World)

Now My Rant on Acad dimensioning in 3D. I know some of the vertical products address 3D making dimensioning easier but in OOTB AutoCAD Vanilla, dimensioning 3D objects in model space is a pain. I have not found out a way to dimension in 3D where the dim extension lines, text, etc. are all on the same plane the nodes are on; not without a convoluted process that takes a lot of time. The nodes will be attached to the object snap you pick (endp, quad, etc.) but the lines and text all go to the base plane of whatever UCS you're set on (i.e., z=0). As a work around I just make a dimension in each plane I need; fix it so everything is on the same plane; then copy it to other places and stretch the nodes to the snap points. ... which is another convoluted method but it works. ... and of course associated dims fly out the window but it gets the drawing done.

Not sure I helped the OP. I got a little off track.
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