Millimeter Precision

Hello I am starting with Sketchup web free, and intend to upgrade, however I am working with building desktop objects for 3d printing, so I need millimeter precision at least. I have looked for ways to set the precision to at least tenth of millimeter, but i don’t see this option. Is this only in the paid versions? I understand there is an inherent limitation of precision and sketchup is designed for larger objects such as architecture, but is 0.1mm out of the question?

You can adjust Display Precision in Mode Info on the right.

My God, thank you. I looked everywhere but did not see that and would not have stumbled upon it… Thank you sooo much

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And also, if you haven’t yet found out, for 3D printing, it is usually advisable to work in SU in metres, as if they were millimetres (or inches).

When you export to STL (which is a unit-less format) tell SU to export in metres, and the slicer to import in mm.

This avoids what is called the ‘small edges’ problem in SU. As it was designed originally for architects, and for use initially in north America using US customary units, SU internally saves lengths in inches in a floating point format whose precision is considerable, but finite.

Also, when drawing, SU checks if different points (whose position cannot be represented exactly) are close enough to each other as to be intended to be in the same position. So very small faces with very short edges may have their endpoints or vertices merged. When modelling in mm sizes, this can result in missing faces or edges especially after rounding corners, or using FollowMe.

In practice, this means differences of less than about 1/1000 of an inch are taken as being in the same place.

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Does this mean that designing small desktop objects in Sketchup is just not a good idea? I don’t wish to have to convert things each time i print them… I don’t need micrometer accuracy, but a 0.1mm would be nice.

You can certainly model small desktop objects in SketchUp. Depending on the detail you need and the slicer software you use you might do what I do when modeling for 3D printing. I model in meters and export the .stl without scaling down. Then just choose the appropriate units (millimeters or inches) when I import the .stl. Here’s an example. This is a piece intended to clip onto a tube and secure with a zip tie. As you can see it’s modeled in meters. (This one could have been modeled in millimeters with no problem but it was a handy example.)

And the imported .stl showing dimensions in millimeters.

If you do need the model to be at actual real world dimensions, using the Dave Method eliminates having to scale down. Box did a good tutorial on that which can be found by searching the forum.

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Further to Dave’s comment, most printing software has a scale function that allows you to set the exact size you want once opened. For example, if you open an over large or over small model in Cura there is a setting that will automatically adjust it to fit the workspace, then you can select the scale tool and type in one dimension and it will scale all 3 to match.
But it only takes a few tests to find what the optimal export settings are to open at the correct size in your printer.

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Thank you all for your help!
Doug

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