Middle point bug???

Hi guys,
in this release (0.6.0057) but also in previous releases I have a problem with the middle point of a curve.
First of all I know two methods to find the middle point of a curve

1)POINT ON CURVE and set slider at 0.5
2)EVALUATE CURVE and set 0.5 as curve parameter to evaluate

Are there others methods to obtain it?

In the attachment file,I made (with 0.6.0055 release,same thing in 0.6.0057)a definition where you can see the error I had found: middle point is not the same.(IMPOSSIBLE)
Is this a bug or my personal error?

Thank you in advance...

Luca.

Tags: middle, point

Attachments:

middle point error1.jpg, 70 KB

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Permalink Reply by David Rutten on January 9, 2010 at 10:22am

Hi Luca,

reparameterizing will not make the curve progression linear, it will merely adjust the domain to go from zero to one. There is never any guarantee that the value in the middle of the curve domain is also in the middle of the curve length. This is true for some curve types (arcs, circles and lines notably), but not all.

The [EVAL] component samples the curve along the domain, whereas the [POINT ON CURVE] object ignores curve parameters and evaluates a curve using length based algorithms. You want to use [EVALUATE LENGTH] instead of [EVALUATE].

--
David Rutten
david@mcneel.com
Poprad, Slovakia