How to ground arbitrary geometry?

[joh13399]

Hello, I have a sketch with 3 lines, 3 arbitrary, and one line connecting the midpoints of each. The midpoint connecting line has a dimension, like so: 

I want to edit this dimension, to make it 0.5 inches. However, when I edit this dimension, I do not want the line on the right to move at all. relative to the origin, all distances should be equal before and after the operation. This does not happen however, and the result is that both lines move.

Given that these 3 lines are completely arbitrary, how do I pin the line on the right such that its' position relative to the origin, and its size do not change? In assembly mode, I believe this is called grounding an entity.

[jhackney1972 · Accepted solution]

While in the sketch, select the line on the right and then select Fix, using your mouse, on the Constrain menu.

[joh13399]

This works well, it may be prudent to note that 'fix' only fixes the angle of the line, it seems that the length can still change if fixed.

[SBix26]

Then you will need to fix the end points as well.  Easiest is to window select all of it, then Fix will get all three entities.

But... Fix is almost never the best answer.  Best to connect the line to the origin with constraints and dimensions.  Is the origin center point projected into your sketches?  There is an Application Option to do that, and I strongly recommend it.

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Sam B

Inventor Pro 2023 | Windows 10 Home 21H2