The “Create Group from Slice” command in the right-click menu of a selected Section plane, does not create the slice exactly where the section cut is positioned but 0.025mm off.
Incidentally, we know that the internal tolerance of SketchUp is 0.025 mm. Whether this is a coincidence or deliberate, I don’t know but this issue creates a problem.
Demonstration.
Note, I am moving the slice group 1cm away from the midpoint, to be able to show that the original position of the group was 0.025mm off the midpoint.
I believe that’s intentional, not a bug, so that those edges will show even with the section cut turned on. TIG’s Section Cut Face extension does the same thing. If it was exactly in the same plane as the section cut, the edges wouldn’t be displayed (nor would the face with TIG’s extension. If that 0.025mm displacement is an issue, group the object(s) getting cut along with the section cut, make the group from slice, cut it from the group and paste in place outside, and finally move it the 0.025mm toward the cut.
Thank you Dave!
I usually create slice-groups and move them somewhere else, but thank you for the workaround!
The question however is - is the group created at the exact location of the section plane and then moved 0.0254mm away? Or does the section plane “lie” about the actual its position and shows one position but in reality, generates the cut at 0.0254mm from its location?
An exaggerated example: Imagine it’s not 0.0254mm but say 25mm away,
Your section plane is in position X. You create a sliced group, which pops up 25mm away from the section plane.
Now question -
• Was the cut generated where the section plane originally was and then moved 25mm ?
• Or was the section plane moved 25 mm, the cut was generated, and then the section plane was moved back 25mm.
Needless to say, of course within 0.02540 mm it’s impossible to have any geometry. But just for the sake of it, if it was more, that would be quite a scandal.
And to be fair, even at 0.02540mm the blue selection box of the generated slice-group is barely noticeable. How much added-value it brings, to move the group away from the plane, is an open discussion. Personally I wouldn’t move it.
The group from slice is made based on the geometry located 0.024mm away from the section plane. Here’s an example. I placed the section plane at x=0 and created the group from section. Note the x-coordinate for the corner of the group. I dimensioned the height of the group from slice and the height of the component at x=0. In this case there’s a difference in dimension of 0.000832mm about one sixth the diameter of a human hair. In reality you couldn’t measure that difference with normally available measuring tools.
