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Table Of Contents
276 | Chapter 12 Creating Parts
4 Create a horizontal dimension between the centers of the left and right arcs.
Select first object: Specify the left arc center (1)
Select second object or place dimension: Specify the right arc center (2)
Specify dimension placement: Place the dimension (3)
Enter dimension value or [Undo/Hor/Ver/Align/Par/aNgle/Ord/Diameter/pLace]
<0.9797>: Press
ENTER
5 Dimension the distance between the centers of the top and left arcs.
Select first object: Specify the left arc center (1)
Select second object or place dimension: Specify the top arc center (4)
Specify dimension placement: Create a horizontal dimension (5)
Enter dimension value or [Undo/Hor/Ver/Align/Par/aNgle/Ord/Diameter/pLace]
<0.5135>: Press
ENTER
6 Press ENTER to exit the command.
In this case, you do not change the values while you create the dimensions.
While a sketch is underconstrained, dimension changes can cause it to dis-
tort, and you may not be able to recover its correct shape.
Creating Constraints Between Features
The sketch geometry is now completely defined. However, to position the
sketch symmetrically on the base feature, you need to constrain the sketch to
the work plane and the work axis because they serve as centerlines for the part.
You use the project (PR) constraint to project points onto objects (similar to the
NEA object snap) and the concentric (C) constraint to force two arc or circle
centers to be coincident.
As you determined when you first analyzed the part,
The left and right arcs of the sketch form the lugs for the saddle bracket.
The arc centers must lie on the work plane.
The top and bottom arcs of the sketch form the base for the boss, in the
exact center of the part. The centers of both top and bottom arcs are coin-
cident with the intersection of the work plane and the work axis.
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