About Archicad's design tools, element connections, modeling concepts, etc.

ArchiCAD presission and tolerance


Hello, I'm learning ArchiCAD and come from a background of Rhinoceros expertise. I'm used to working in mm with 0,001 tolerance. When I model in ArchiCAD, while being careful of making precise snaps and 90° lines, I'm always getting small unalignments, like after some time modelling, something that should measure 1000 mm is 1001 mm... is this normal or I have to pay closer attention towards what I'm snapping to?

Barry Kelly

If you are working in mm, the maximum precision for Working Units in Archicad is 0.1mm (one decimal place).


To help with accuracy, turn the (blue) snap guides on.

Use the SHIFT key to constrain the cursor horizontally, vertically or to pre-set angles (in the Work Environment).


Also turn the tracker on so you can see exactly what you are doing.


Never just stretch or draw an element and click to place based on what you are reading in the co-ordinate box or tracker.

Always type the distance you want.


Read up about the tracker and snap guides in the Help Reference ... There is a 'Product Help' link at the top right of this community.




Also have a look in Graphisoft Learn ...

There may be some tutorials you can do that will help.




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AC isn’t designed to work with those Rhino tolerances when it comes to dimensions on drawings. It is based on building tolerance rather than engineering e.g. we’re cutting bits of wood, not machining engine parts. I do drawings for offsite fabrication where even working to 0,5mm is optimistic. You should be able to draw to 0.1mm without a problem, if you’re seeing 1mm error that isn’t caused by rounding** then please follow @Barry Kelly  excellent advice. 

**Rounding problems have been an issue with CAD forever and there have been plenty of discussions on this forum. 

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