Sketch in Drafting
Sketch in Drafting
(OP)
NX 6.0.5.3
On the drawing sheet, I create 2 vertical lines. I then create a horizontal dimension between those lines, selecting the mid-point of each.
Why the warning ... "Some of the selected objects or snap options are not allowed for driving dimensions" ? What's the issue with selecting the mid-points ?
On the drawing sheet, I create 2 vertical lines. I then create a horizontal dimension between those lines, selecting the mid-point of each.
Why the warning ... "Some of the selected objects or snap options are not allowed for driving dimensions" ? What's the issue with selecting the mid-points ?
Specialty Engineered Automation (SEA)
http://www.sea4ug.com
a Siemens PLM Solutions Partner





RE: Sketch in Drafting
And when if comes to curves, they are all defined by 'points', some are obvious and some are not. In the case of a Line, it's the start & end points. An Arc, the center point and the start & end points (even if it's a full circle). A Spline, the knot points. An Ellipse, the center point and the start & ends points (same as an arc/circle). A Conic, the start & end point as well as the control point. In each case, the common DEFINING characteristic was a 'point'.
Therefore when it comes to creating DRIVING dimensions, you can only select a DEFINING point. With 'reference' dimensions (which are still associative, just not driving), in addition to DEFINING points, they can also reference the so-called 'snap points'. Now if a snap point turns out to also be a DEFINING point, such as End Points, or an Arc Center, or a Knot (control) Point, then dimensions which reference them can also be DRIVING dimensions. Generally speaking however, Snap Points such as Mid-Point, Intersection Point, Point on Curve, Point on Face, Quadrant Point and some Control Points, can never be DEFINING points and therefore cannot be referenced by DRIVING dimensions.
Anyway, I hope this clears-up a few things and that it helped you understand better what's happening when you're Sketching on the face of a Drawing.
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.