topic Re: Area in AutoCAD Forum

Area

graziolicorradoKLTL3 — Sun, 24 Nov 2024 20:31:33 GMT

Sera,

come si vede dalle immagini allegate,

l' area della prima polilinea ricavata dalle proprietà è 2.05,

utilizzando il comando area si ottiene il medesimo risultato.

L' area del retino inserito nella stessa polilinea è 2.76, in teoria dovrebbero essere uguali.

Perchè tale differenza?

Re: Area

leeminardi — Mon, 25 Nov 2024 17:16:57 GMT

I created an 8 CV spline of degree 2 simila to the shape you posted. I modified the weights of some of the CVs as it appears is the case in your drawing. The area of the spline and the area of hatchinging referencing the spline were the same,

Can you post your drawing file?

Re: Area

graziolicorradoKLTL3 — Mon, 25 Nov 2024 17:40:22 GMT

Sera, allego field area.dwg.

I valori di area sono ottenuti direttamente col comando field, anche il comando area e la paletta proprietà danno gli stessi valori

Re: Area

leeminardi — Mon, 25 Nov 2024 18:27:14 GMT

It appears that the hatch command may assume that the weights of a CV in a degree 2 spline are all equal to 1.0. Changing CVs 2, 4, 6, and 8 to 1.0 (from 0.89) in your drawing yields an area consistent with the hatching area. Changing the weight does alter the shape as seen below. The white spline has all the weights set to 1.0. You can see that its shape is slightly larger than the original red spline. The properties and area/object show the correct value. The hatch area is incorrect and should be treated as an approximation.

Re: Area

paullimapa — Mon, 25 Nov 2024 18:40:37 GMT

if spline area is negative:

https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Area-property-of-closed-Splines-is-incorrect-or-negative-in-AutoCAD.html

I used BPOLY and made it into a Region and now get the correct area:

Re: Area

graziolicorradoKLTL3 — Mon, 25 Nov 2024 19:54:36 GMT

Grazie mille a tutti ,

usando il comando bpoly o boundary per creare una regione il valore dell area è uguale in entrambe i casi

Re: Area

paullimapa — Mon, 25 Nov 2024 19:59:11 GMT

glad to have helped...cheers!!!