>I typically Construct a field from bits and pieces returned by Pick.
>Select 'closest vertex' and send it to Construct origin; in parallel,
>Select 'old positions' and send it to (the same) Construct data. You
>should have a field with one position and one vector data item
>attached to it corresponding to the original position that you pushed
>over into a user-named data array ("old positions").

I am doing this, but isn't the "old position" then an interpolated value
attached to a non-interpolated "new position" (closest vertex) ? The goal is to
get the positions (as defined, not interpolated) of a single data point from a
transformed image displayed on the screen.

I don't think Include works on vectors: I can't
>remember but I think it may force the mag(a) on input so then you get
>all vectors with the included magnitude which is obviously worthless
>here.

Include is used on the big object (a field) displayed in the Pick'ed image.
When you say vector, are you thinking I'm using Include on just the pick
positions ?.

--- Forwarded mail from [email protected]

Date: Tue, 20 Mar 2001 07:38:18 -0500
To: [email protected]
From: Chris Pelkie <[EMAIL PROTECTED]>
Subject: Re: [opendx-users] picking from transformed object
Reply-To: [email protected]

>How do you get original positions back out after picking from a transformed
>object and extracting the closest vertex ?
>
>I've tried saving the original object positions under some other component
>name, and I am able extract these positions from the pick point, but not from
>the closest vertex (the created component is lost since this entity is not a
>field).
>
>Since this approach didn't work, I marked "old positions" of the full object
>and did an Include with min and max equal to closest vertex (transformed
>positions), hoping to get a field with one data element in it. I could then
>extract "old positions" of this element to get the original positions of the
>closest vertex. The problem is that I can't get one data element
>using include.
>If min=max, the field contains no elements. If I add some small value to the
>max and subtract some small value from min, I get too many elements.
>
>Is it possible to grab a specific data element from a field, or is there
>another way to get original positions back from the closest vertex to the
>(transformed) pick point ?


Chris Pelkie
Vice President/Scientific Visualization Producer
Conceptual Reality Presentations, Inc.
30 West Meadow Drive
Ithaca, NY 14850
[EMAIL PROTECTED]


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