Inventor User Coordinate System (UCS)

TECHNICAL WHITEPAPER
Inventor User Coordinate System (UCS)
Introduction
Every Inventor Part and Assembly has an Origin folder. The Inventor User
Coordinate System (UCS) gives the designer the ability to have as many user
origins as desired. They contain the same members as the Origin folder and can
be used for the same purposes. UCS have one feature that makes them very
special, they can be moved and/or rotated unlike the Origin folder features. This
makes them very valuable in the design process.
Table of Contents
■■ Introduction
■■ Uses for User Coordinate System
■■ User Coordinate Configuration
■■ Placement of UCS in Part Model
■■ Example of UCS Applications
Uses for User Coordinate System
■■ Conclusion
There are too many uses to list but here are some of the top ones:
■■ About the Author: John R. Hackney,
Manufacturing Solutions Consultant
In Part Modeling:
■■ Provides dynamic work planes for sketches and features. If the sketch or
feature is modeled on a UCS work plane, then the UCS is redefined, either moved and/or rotated, the sketch or feature
moves with it.
■■ Provides another way to position work planes and axis in the model which is often quicker and more robust than using
the traditional work features. Once placed the work planes can be used for splits, measurement or termination planes to
mention a few.
In Assembly Modeling:
■■ Parts can be constrained together using any UCS features contained in them. The assembly constraint will automatically
adjust to changes in the location and/or angle of the UCS in the part.
■■ UCS work planes can be used for quick viewing using the “Look At” command.
In Drawings:
■■ UCS features can be included in the model drawing and can be used for reference dimensions.
User Coordinate Configuration
The UCS command can be configured in the Inventor Part and Assembly templates to follow a specific set of rules. After a UCS
has been created, it appears in the browser and may be edited for visibility at any time. The prefix name cannot be edited once
it is placed. The configuration command is found in the shown location.
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In the UCS Settings dialog, everything is self-explanatory except the “Default plane”. Once the UCS is placed in the model, the
“Default plane” affects the behavior of sketch and face view commands.
Placement of UCS in Part Model
UCS are placed using points (including midpoints), vertices, centers and work points. After executing the command, which is
found on the Work Features panel, it will prompt you for three points. The first one is the origin point, then a point to define the
X direction and last the y direction. Once all conditions are satisfied, the UCS is saved in the browser. Each UCS uses the
naming prefix and a consecutive number. A UCS is shown below with the default configuration. Notice the triad, and the three
axis are visible.
If you right click on the UCS in the browser, you can choose the “Redefine Feature” to change the location and/or rotation. If you
decide to relocate the origin, select the blue ball and select three points in the same way used when you originally created the
UCS. If you only wish to move the UCS allow one of the axis, select the direction arrow head and specify a distance which can
be negative or positive. If you wish to rotate the UCS, select the axis bar (between the blue ball and the arrow head) and specify
the desired angle. This also can be negative or positive. Positive rotation is clockwise if you are looking at the arrow point.
For example, I am rotating the UCS around the X axis plus 30 degrees. The before and after pictures are shown below.
After you are finished editing the UCS, right click and select “Finish”. If you really mess up, right click and select “Restart”.
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Example of UCS Applications
Moving a feature
In this example, the slot was created on UCS:1 X-Y Plane. If the UCS:1 is redefined to another face of the block, the slot moves
with it. Take care to select points that keep the extrusion direction through the block or you will have to redefine the direction of
the extrusion cut.
Creating a UCS Work Plane for Use with the Split Command
The split shown below was created by the X-Y plane of the UCS. The UCS was created on the corner with the X-axis point at the
vertex of the yellow side edge and the Y-axis point at the vertex of the original red side edge. The “Redefine Feature” command
was used to select the Y arrow to move the UCS 0.75” down the red face edge. Then the X bar (between the blue ball and the X
arrow during editing) was selected and an angle of +30 degrees was applied.
As an Assembly Constraint Feature
Combining Parts with UCS features is a delight using a dedicated assembly constraint. The channel beam must be centered on
the plate. This would take at least three calculated flush and mate assembly constraints.
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Inventor User Coordinate System (UCS)
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Select the “Place Constraint” command from the Assembly Tab, Relationship Panel and select the “Constraint Set” tab.
Select each of the part UCS icons and you are done.
The assembly constraint uses three flush constraints between the three planes of each UCS so if you need to adjust the position
of the channel, these can be modified.
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The beauty of this method is if one of the part UCS is redefined, the assembly will update automatically. In the below image,
the channel UCS has to be rotated about the Z axis +30 degrees. This in turn will rotate the channel, in relation to the base,
-30 degrees looking at the Z axis arrow.
Conclusion
The uses for the UCS is only limited by your imagination. The next time you are faced with the creation of a particularly hard work
plane or you have a challenging assembly constraint, give the UCS command a try.
About the Author: John R. Hackney, Manufacturing Solutions Consultant
John has 25 years of experience in the manufacturing industry including experience in Converting Machinery, High Speed Pick and
Place, Packaging Machinery, and Waste Incineration Equipment. He has served as CAD Manager, Designer, Quality Control Checker
and Engineering Manager during his manufacturing years.
John is currently an IMAGINiT Technologies Manufacturing Solutions Consultant and is an Autodesk Inventor Certified Professional.
His current assignments include Autodesk Application Implementation, Training and Contract Engineering Assistance using a variety
of Autodesk applications including Autodesk Inventor, AutoCAD Mechanical, AutoCAD Electrical and all versions of Autodesk Vault.
About IMAGINiT Technologies
IMAGINiT Technologies, a Rand Worldwide Company, is the world’s largest provider of enterprise solutions
to the engineering community, including the building, manufacturing, civil and mapping industries. With
over 25 years of experience, and 45 offices throughout North America, we provide the expertise, training
and support to help companies realize the full power of design technology, maximize ROI and gain
competitive advantage.
IMAGINiT is a leading provider of Autodesk software solutions and the largest North American Autodesk
Authorized Training Center (ATC) partner. All of our locations are supported by a vast pool of engineering
resources focused on developing real-life business solutions for their local clients.
[email protected]
800.356.9050
www.imaginit.com