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Message 1 of 12 (460 Views)

# What is the difference between World UCS and Top UCS

460 Views, 11 Replies
02-15-2013 08:43 AM

Question - What is the difference between the world UCS and the top UCS?

I am working in a faily large model and when I have the UCS set to world and do the ID command I get the correct coordinance. However when I am in a plan view and UCS is set to top the coordinance come in roughly 600 feet different. Can anyone tell me how to set the UCS so that coordinance will be the same no matter what UCS is being used? Or explain why this would be?

Thank you!

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Posts: 204
Registered: ‎09-10-2012
Message 2 of 12 (411 Views)

# Re: What is the difference between World UCS and Top UCS

02-19-2013 06:06 AM in reply to: ryan0416

The TOP UCS is a relative UCS. Aty the start the TOP and WCS are the same.

Lets say for example that you have a box drawn nice and square to the WCS. if you were to rotate the view to get a 3D look at the box you may wish to draw something not on the XY plane. so we use the UCS command and define a new reference XY plane. The TOP UCS is now planar with the current XY plane and also the TOP USC is no longer planar with the WCS (which is CONSTANT for a drawing).

Hence the TOP UCS is set by using the UCS command and is relative

HTH

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Posts: 204
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Message 3 of 12 (407 Views)

# Re: What is the difference between World UCS and Top UCS

02-19-2013 06:11 AM in reply to: ryan0416

Also if you have set a custom UCS which happens to be co-planar with the WCS then the WCS and TOP ucs's will have different origin points and thus different ID values

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Message 4 of 12 (396 Views)

# Re: What is the difference between World UCS and Top UCS

02-19-2013 06:43 AM in reply to: Nik-D

Ok, so if I am getting different coordinates when I ID a particular point how do I change the UCS so that no matter what view I am in I will get the same coordinates? The only way I was able to solve the issue was to start with a fresh file.

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Posts: 204
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Message 5 of 12 (383 Views)

# Re: What is the difference between World UCS and Top UCS

02-19-2013 08:04 AM in reply to: ryan0416

set your UCS to world - Type - USC (enter) W (enter)

Set the WCS current and regenerate layout - Type - PLAN (enter) (enter)

Draw a horizontal XLINE through the current origin

type UCS, then select the origin followed by some point on the XLINE to the RHS.

Your TOP UCS should now be in the correct location

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Posts: 16
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Message 6 of 12 (381 Views)

# Re: What is the difference between World UCS and Top UCS

02-19-2013 08:07 AM in reply to: Nik-D

Ok, Thanks! I will give that a try on my old model. I appreciate the help!

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Registered: ‎01-03-2008
Message 7 of 12 (251 Views)

# Re: What is the difference between World UCS and Top UCS

05-29-2013 11:11 AM in reply to: ryan0416

It's easy enough to temporarily move the UCS anywhere I'd like it to be, but the Top UCS resets to a point different from the World UCS every time I set the view back to Top.

what I'd like to understand is why the Top UCS is different from World in this particular drawing, and how I reset it to be the same as World UCS, permanently.

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Message 8 of 12 (237 Views)

# Re: What is the difference between World UCS and Top UCS

05-29-2013 06:52 PM in reply to: ohnoezitasploded

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Message 9 of 12 (226 Views)

# Re: What is the difference between World UCS and Top UCS

05-30-2013 10:31 AM in reply to: ryan0416

I've set it to both 1 and 0, it doesn't affect this behavior-- i.e. when I set UCS to Top, it still moves the base point away from the World UCS.

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Message 10 of 12 (211 Views)

# Re: What is the difference between World UCS and Top UCS

06-02-2013 01:52 PM in reply to: ryan0416

as others have said , if you are using ID to get coordinates, make sure you are always in the same coordinates system.

Be it either WCS  or another UCS , does not matter, as long as you do not change.

This way coordinates all have same origin .

WCS is the easiest :  just type ucs , and w  for World

if you use UCS , it can be saved. with the same command :  ucs , named and save

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