buildingSMART Forums

Precision setting best practices

“Value of the model precision for geometric models. It is a double value (REAL), typically in 1E-5 to 1E-8 range, that indicates the tolerance under which two given points are still assumed to be identical. The value can be used e.g. to sets the maximum distance from an edge curve to the underlying face surface in brep models.”

What’s the precision value best practice? Should we consider the length unit information of data? say a model with meters use 1E-5 seems reasonable, however a model with millimeter use 1E-5 seems too tight.

I believe it depends on the tolerances of the software you use. In my case I have established a limit of 1E-07 for meters and scaled accordingly to the units, so 1E-04 if in millimetres

Thanks for the input. That sound reasonable to me.

I’m not well on geometry/topology, but as long as I know, in implicit geometry representations, two-three tolerance indicators matter, one is distance, another is angle, and one other I think which I’ve forgotten