Hello. I notice a problem in rhino 8 when i use large coordinates. In my example i start a simple polyline at point with coords: 474350,4203130 but when i evaluate my point i get: 474350.00000047,4203130.000004201 Why? precesion_lost.3dm (47.3 KB)

[image] Ar00302: But in MicroStation i see the differences of -0.00000047 in x and -0.000004201in y. Logged as RH-78907 Precision Display Issues in Rhino 8?

[image] Ar00302: I am waiting for an answer from mcneel about this I think you’ll get the same answer…

[image] Ar00302: why in a simple key in of integers I take floating numbers Rhino only uses floating point numbers. But 4,200,000 should be well inside the range of integers that double precision floating point can store accurately. Double-precision floating-point format Double-p…

That’s why Rhino doesn’t show you “full precision” anymore, to avoid these questions about what is just noise, which every other program just hides from you.

[image] Ar00302: Still don’t understand why in a simple key in of integers I take floating numbers. No calculations take place here. In fact I can afterwards move by -0.00000047 and -0.000004201 and get the Integer numbers I need. Look up how to convert base-10 numbers into binary double-prec…

[image] Ar00302: 474350,4203130 Well, if I take the X coordinate 474350.00000047 and I try to find what part of the whole the last .00000047 is by dividing 0.00000047 / 474,350 I get about 1e-12. Rhino’s “Zero tolerance” is 2.3283064e-10 i.e. quite a bit larger than that. https://develo…

what type of calculation rhino does when i key in an integer like 474350? how its translated to 474350.00000047?

Points are still saved with double type. If your document tolerance is say 0.0001 then it is still within tolerance. It is all down to arithmetics with floating points, be they single or double float, and how computers can express those numbers in memory. For fun do in Python using _ScriptEditor: …

[image] emilio: But 4,200,000 should be well inside the range of integers that double precision floating point can store accurately. Yes absolutely correct. I made a copy of the line .00000002 meters to the right and then moved that copy .00000004 meters upward and then exported both lines a…

i am having same troubles. getting imprecise coordinates when working with whole numbers and even when close to origin.

Let me leave this with you. [fp error] Then please read thoroughly through Floating-point arithmetic - Wikipedia and come to understand that there are numbers that cannot be represented, especially after computation done on them, like evaluation of points. Also, 1e-12 in say a millime…

Precision problem in large coords

Rhino

brian (Brian Gillespie) December 7, 2023, 6:12pm 21

Logged as RH-78907 Precision Display Issues in Rhino 8?

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Precision problem in large coords

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