# Smallest dimension possible

I am trying to draw something that is 1 micron. I have gone into

Window -> Model Info -> Units

changed units to decimal with a precision of 0.0000 mm and length snapping of 0.001 mm. Yet when I try to draw something with one dimension of 0.001 mm (1 micron) I get an error stating that dimensions cannot be zero. I get this error for anything less than 0.1 mm. Does anyone know how I can resolve this?

Thank you so much!

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Hi majdit, hi folks.

This is too small. SketchUp (SU) has difficulties when dimensions are smaller than 1 mm. Try drawing larger than real life using a larger unit like meter. When done, you can scale it down. For microns, it will need to be scaled two times by 0.001 to obtain a scale factor of 0.000001 since SU cannot use a scale factor less than 0.001.

However, I dont recommend that you scale that small since SU will interpret such small dimensions as 0. Stay with meters and pretend that they are microns.

I also suggest that you do not set the Length snapping since SU provides very good inferencing system and allow you to input precise values in the Dimension Window.

Just ideas.

Jean

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SketchUp uses an internal tolerance of `0.001` inch (`0.0254mm`)
Entering dimensions less than this is basically frivolous, IMO.

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Thanks so much Jean. As it turns it you canâ€™t scale down twice at 0.001 to achieve micron resolution. The image disappears. It was worth a shot. Though.

Thanks so much DanRathbun.

If Sketchup only has an internal tolerance of 0.0254mm why does it have a precision setting of 0.000000 mm? You can find this in model info when you change the units to mm.

precision and tolerance are quite differentâ€¦

1.000025 is a valid input using that level of precisionâ€¦

john

Thank you John_drivenupthewall.

I am not allowed to input something that is 0.001 mm. It fails at this task.

An input of 0.001 mm implies that two endpoints end up that close. SketchUp merges endpoints with distances less than 0,0254 mm apart. (see @DanRathbunâ€™s post above)
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@john_drivenupthewallâ€™s input however implies endpoints to be more than 0,0254 mm apart.
(1.000025 mm> 0.0254 mm).

Thank you Wo3Dan.

Sketchup has a snapping option that allows you to snap items to a grid of 0.000001 mm. Iâ€™m not sure why this option would exist if it merges two points that are 0.0254mm apart!

Because it can apply to drawing an edge which is not aligned with any of the axis. A diagonal edgeâ€™s length needs the extra precision, if you are to snap to vertices that are on SketchUpâ€™s â€śinternal tolerance gridâ€ť.

But as Jean said above, with SketchUpâ€™s built-in inference snaps, using a â€śvirtual gridâ€ť is not really needed.

Thank you DanRathbun. I still donâ€™t understand why such high precision setting are available as they cannot be used. Regardless, I really appreciate your feedback as I now have a clearer understanding of the limitations of Sketchup.