Movement precision problem
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Hi, I'm new here, just as I am new to Sketchup 2014 (last time I used Sketchup was back when it was called Google Sketchup, in 2008 or so I think). Anyway, I am laying out an array of cylinders in 3D Printer mode (millimeters). The cylinders need to be .131 mm apart as measured from their edges, and I've had no problems lining them up with a guideline. But when I start moving a cylinder (actually it's a move + copy) by typing in the precise amount of distance I want the cylinder moved, it seems to have a mind of its own as to how far it wants to go. There seems to be anywhere from .01 to .02 mm error in placing the object, and it seems to repeat the same error over and over when I attempt to make corrections. I've managed to line up several cylinders properly after repeatedly moving them around with the mouse and changing the distance between the cylinders to be aligned until it finally accepts my specified distance, but now that I have a large group I need to align, it seems to have gotten stuck in a rut.
Any idea what might be causing this, or what I can do about it? Is this a software-related problem? Could it be problems with my CPU's FPU calculations? It's a Sempron 140 + 8800 GTX Ultra vid card, fwiw.
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It sounds like you have Precision set coarser than what you need and perhaps Length Snapping is enabled. Increase Precision and disable Length Snapping and see if that helps. Look under Window>Model Info>Units.
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@dave r said:
It sounds like you have Precision set coarser than what you need and perhaps Length Snapping is enabled. Increase Precision and disable Length Snapping and see if that helps. Look under Window>Model Info>Units.
According to the units submenu, length snapping is disabled and precision is set to ".000000mm" which is the highest precision setting. Granted, I only just now checked that submenu on your advice (thanks!).
I found a workaround: I scaled the model to ten times its normal size and my movements worked just fine. Now I'm resizing back to 1/10th the current size. Too bad each resize operation (blue, red, green) takes about 2-3 hours to complete. My Sempron is pegged at 100% CPU utilization, poor thing. It is time for an upgrade.
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How big are these cylinders? You shouldn't have to be scaling up and down to do this.
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@dave r said:
How big are these cylinders? You shouldn't have to be scaling up and down to do this.
.38mm in diameter and 3mm in length. They need to be .131 mm apart measured from the edge in the x/y dimensions (.511 mm as measured from the vertical axis through the center of any given cylinder).
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SketchUp tells me that .19mm radius is too small so you probably ought to work at some larger scale and scale down when you're finished modeling. I expect you're working at below the tolerances built into SketchUp.
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@dave r said:
SketchUp tells me that .19mm radius is too small so you probably ought to work at some larger scale and scale down when you're finished modeling. I expect you're working at below the tolerances built into SketchUp.
Yeah, that's what I had to do. I wouldn't even let me create a .19mm radius circle to start, so I had to scale it down. Then when I made copies and started moving them around . . .
In any case, I've learned my lesson. Thanks!
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SketchUp will baulk at making an edge < 1/1000th inch.
It will consider the two points that are needed to make it to be coincident !
0.5mm is about the limit.
1mm is safer.
Any operations like a Circle or FollowMe etc which try to create very tiny edges will fail because of this 'limit'.
Hence the Scale up 'trick'...
These kinds of tiny edges can exist [e.g. when you Scale down afterwards] - but they cannot be created.
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