# I've noticed that Blender changes the size of my Meshes by himself. Is it allright?

I have one mesh 10m*2m*20cm for example. When I check it's size in N-window it shows 20cm - here it's ok. But when I duplicate this mesh and rotate it on 90 degrees - mesh's size changes by itself! When I click again on the size line in N-menu it shows me not "20cm" but "20.000002cm". So the change is very small but still it's not normal. It doesn't happen all the time I work with the copy of the mesh and I can't actually find out when it happens. But i face this changing quite regularly.

Blender version 2.79. Is that ok? I wonder how I can avoid this bug.

• This is caused by the precision of the floating point numbers. I'm not entirely certain how long floating pointing numbers Blender uses internally, but this is not a bug, and the only way to make it not happen, is to change how floating point numbers are handled. But you can work around it. After applying the rotation, manually enter the correct dimensions in the properties panel, then apply the scale Alt A followed by S. By honestly, why bother with .02 µm? – Duane Dibbley Dec 26 '17 at 18:07
• Because anyway 20cm and 20.000cm is not the same and i'm afraid of holes in my models when meshes don't stick to each other well. I would be happy to avoid it. – wooden_coder Dec 26 '17 at 18:41
• Your mesh has a 10m side, another of 2m, and you worry about a tolerance of .02 µm ? Even in reality things are not that precise... any item you have in your house (including the house) is far less precise than that... – m.ardito Dec 27 '17 at 8:19